Sleep study sensor and transmitter and method with reduced manufacturing costs and / or reduced power consumption

Abstract

Systems, devices, and methods are provided for sensing and transmitting Respiratory Inductive Plethysmograph (RIP) signals. The devices include an oscillator circuit comprising an inductor from a RIP sensor and a capacitor, wherein the oscillator circuit is configured to generate an oscillator signal; an amplifier circuit connected to the oscillator circuit, wherein the amplifier circuit is configured to receive as an input an AC component of the oscillator signal and to output an amplifier output signal based on the AC component of the oscillator signal; and a voltage controlled switch connected to the oscillator circuit and to the amplifier circuit, wherein the voltage controlled switch is configured to receive the amplifier output signal as a control input and, when in a closed configuration, to conduct current from an energy preserving power source to the oscillator circuit.

Description

SLEEP STUDY SENSOR AND TRANSMITTER AND METHOD WITH REDUCED MANUFACTURING COSTS AND / OR REDUCED POWER CONSUMPTION

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of and priority to United States Provisional Patent Application Serial No. 63 / 552,054 filed on February 9, 2024, and entitled “SLEEP STUDY SENSOR AND TRANSMITTOR AND METHOD WITH REDUCED MANUFACTURING COSTS AND / OR REDUCED POWER CONSUMPTION” which is expressly incorporated herein by reference.

[0003] FIELD OF THE DISCLOSURE

[0004] The present disclosure relates to systems, apparatuses, and methods for performing a sleep study, and particularly for sensing and transmitting respiratory inductance plethysmography (RIP) signals using a RIP device.

[0005] BACKGROUND

[0006] Respiratory Inductance Plethysmography (RIP) is a non-invasive method for measuring respiratory patterns by detecting changes in thoracic and abdominal cross- sectional areas using a looped wire. RIP appears physically as two belts that the patient wears during a sleep study, one around the chest (Thorax) and the other around the Abdomen. The main reason for measuring RIP in sleep is to derive a flow signal for determining if a patient suffers from Sleep Apnea.

[0007] Sleep Apnea is measured using clinical standards determined by the AASM (American Association of Sleep Medicine). Sleep Apnea is defined by the AASM as an event where the patient undergoes >90% drop in respiratory flow for >10s. The standard measure of respiratory flow is a nasal cannula or thermistor in the nose, indicating the amount of air that is inhaled / exhaled and the 90% is conventionally a drop in the amplitude of those signals.

[0008] There are two different main reasons why a patient has a Sleep Apnea event: an obstruction in the airway (Obstructive Sleep Apnea, OSA) and lack of respiratory effort (Central Sleep Apnea, CSA). OSA is due to body-mechanical reasons, for example tissue blocking the airway, while CSA is of neurological origin, for example when there is no signaling from the brain to breathe.

[0009] The conventional application of respiratory effort signals is primarily directed toward detecting the presence or absence of respiratory effort in the context of Sleep Apnea, thereby enabling the classification of respiratory events as either OSA or CSA. This classification is typically executed as a binary determination, wherein the presence or absence of respiratoryeffort is assessed. Given the simplicity of this binary determination, many sleep monitoring systems implement movement-based sensing mechanisms merely to detect respiratory effort.

[0010] In contrast, RIP technology leverages the principle of electromagnetic induction, where a RIP belt includes a conductive loop that generates an inductive signal proportional to changes in its shape and dimensions. Breathing causes the thorax and the abdomen to change their shape, thus changing the shape of the looped wire around them.

[0011] To illustrate this, the expansion of the thorax (T), the expansion of the abdomen (A), and the total respiratory volume (V) can be expressed as a weighted sum: V=kiT+k2A. This equation represents the relationship between body expansion and the volume of air inhaled. In such an equation, airflow corresponds to the first derivative of volume, dV / dt. By determining V(t), airflow can be derived, eliminating the need for a cannula or thermistor. However, making such a determination requires much more accurate measure of the respiratory movement than would be needed for the OSA / CSA classification only, including higher bandwidth, linearity with volume and good signal-to-noise ratio (SNR).

[0012] Additional features and advantages will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the teachings herein. Features and advantages of the invention may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. Features of the present invention will become more fully apparent from the following description and appended claims or may be learned by the practice of the invention as set forth hereinafter.

[0013] SUMMARY

[0014] A Respiratory Inductive Plethysmograph (RIP) device comprises an oscillator circuit comprising an inductor from a RIP sensor and a capacitor, wherein the oscillator circuit is configured to generate an oscillator signal; an amplifier circuit connected to the oscillator circuit, wherein the amplifier circuit is configured to receive as an input an AC component of the oscillator signal and to output an amplifier output signal based on the AC component of the oscillator signal; and a voltage controlled switch connected to the oscillator circuit and to the amplifier circuit, wherein the voltage controlled switch is configured to receive the amplifier output signal as a control input and, when in a closed configuration, to conduct current from an energy preserving power source to the oscillator circuit.

[0015] A method for capture and low power transmission of RIP signals using a Respiratory Inductive Plethysmograph (RIP) device comprises receiving an oscillating signal generated by an oscillator circuit, wherein the oscillating signal oscillates at a resonance frequency;amplifying an AC component of the oscillating signal to produce an amplified signal; based on the amplified signal, producing an encoded output signal that indicates the resonance frequency of the amplified signal; and transmitting the encoded output signal, wherein producing the encoded output signal comprises: sampling the amplified signal to produce a first sample and a second sample, comparing the second sample to the first sample, and after comparing, reducing a size of the second sample such that the second sample consumes less power to transmit than the first sample.

[0016] BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 illustrates a chart that depicts how RIP signals may be used in a real sleep apnea study where a patient experiences severe sleep apnea.

[0018] FIG. 2 illustrates a graph that depicts how RIP signals may be independent of mouthbreathing.

[0019] FIG. 3 illustrates graphs that depict how well the RIP bands measure breathing amplitude compared with nose cannula.

[0020] FIG. 4 illustrates data that shows the capability of the BodySleep™ algorithm to predict arousal based hypopneas from RIP signals.

[0021] FIG. 5 illustrates a representation of RIP technology according to some embodiments described herein.

[0022] FIG. 6 illustrates how one or more RIP belts may be worn by a patient according to some embodiments described herein.

[0023] FIG. 7 illustrates an example of a RIP product.

[0024] FIG. 8 illustrates an example simulator used to test functionality of a RIP belt according to some embodiments described herein.

[0025] FIG. 9A illustrates a high-level diagram of a Respiratory Inductive Plethysmograph (RIP) device according to some embodiments described herein.

[0026] FIG. 9B illustrates a high-level diagram of a Respiratory Inductive Plethysmograph (RIP) device according to some embodiments described herein.

[0027] FIG. 10 illustrates a detailed schematic of a RIP device according to some embodiments described herein.

[0028] FIG. 11 illustrates a detailed schematic version of an oscillator circuit according to some embodiments described herein

[0029] FIG. 12 illustrates a detailed schematic version of an amplifier circuit according to some embodiments described herein

[0030] FIG. 13 illustrates a bode plot of an amplifier circuit according to some embodiments described herein.

[0031] FIG. 14 illustrates a detailed schematic version of a voltage controlled switch according to some embodiments described herein.

[0032] FIG. 15 illustrates a simulation of current through a voltage controlled switch according to some embodiments described herein.

[0033] FIG. 16 illustrates a depiction of the relative amount of time that a MOSFET remains in each operating mode over varying inductances according to some embodiments described herein.

[0034] FIG. 17 illustrates a detailed schematic version of an offset voltage controller according to some embodiments described herein.

[0035] FIG. 18A illustrates a method of encoding data to be streamed over a wireless connection.

[0036] FIG. 18B illustrates a method of decoding data after it has been streamed over a wireless connection.

[0037] FIG. 19 illustrates a high-level diagram of a RIP device according to some embodiments described herein.

[0038] FIG. 20 illustrates a detailed schematic of a RIP device according to some embodiments described herein.

[0039] FIG. 21 A illustrates a simulation of a RIP device without a series inductor according to some embodiments described herein.

[0040] FIG. 21B illustrates a simulation of a RIP device with a series inductor according to some embodiments described herein.

[0041] FIG. 22 illustrates a high-level diagram of a RIP device according to some embodiments described herein.

[0042] FIG. 23A illustrates a detailed schematic of a RIP device according to some embodiments described herein.

[0043] FIG. 23B illustrates the detailed schematic of a RIP device shown in FIG. 23A with additional components according to some embodiments described herein.

[0044] FIG. 24A illustrates a simulation of a RIP device according to some embodiments described herein.

[0045] FIG. 24B illustrates a simulation of a RIP device according to some embodiments described herein.

[0046] FIG. 25A illustrates a top plan view of an embodiment of a RIP device described herein.

[0047] FIG. 25B illustrates a perspective view of the RIP device according to FIG. 25A.

[0048] FIG. 25C illustrates a perspective view of a RIP device that shows an interior of the RIP device according to FIG. 25A.

[0049] FIG. 25D illustrates a side view of the RIP device according to FIG. 25A.

[0050] FIG. 25E illustrates a side view of the RIP device according to FIG. 25A.

[0051] FIG. 26 A illustrates a perspective view of an embodiment of a RIP device according to some embodiments described herein.

[0052] FIG. 26B illustrates an enlarged view of the RIP device 2600 of FIG. 26A.

[0053] FIG. 27 illustrates a buck and boost RIP device according to some embodiments described herein.

[0054] FIG. 28 illustrates a RIP device according to some embodiments described herein.

[0055] DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

[0056] An object of the present application is to provide systems, apparatuses, and methods for performing a sleep study, and particularly for retrieving Respiratory Inductance Plethysmography (RIP) signals that have good bandwidth, linearity with volume and good SNR. Another object of the present application is to provide such in a cost-effective and reliable manner. A further object of the present application is to provide such that have a significantly improved power efficiency.

[0057] 1 - Introduction

[0058] In this disclosure, the design of a new RIP device circuit configured to generate RIP signals is provided. FIG. 1 illustrates a chart that depicts how RIP signals may be used in a real sleep apnea study where a patient experiences severe sleep apnea. In the study, the RIP signals 110 were recorded along with several other sensors placed on a patient. The cannula nasal flow 120 drops to close to nothing while the individual gasps for air. This is followed by a desaturation in the oximeter signal 130. The RIP signals 110, specifically the Thorax and Abdomen, show movement the whole time, indicating that the patient is still trying to breath with limited results. The phase shift between the Thorax and Abdomen confirms that this is an obstructive sleep apnea.

[0059] Turning now to FIG. 2, FIG. 2 illustrates a graph that depicts how RIP signals may be independent of mouth-breathing. In FIG. 2, a pneumotach reference airflow 210 is compared with a nasal cannula signal 220 and a RlP-flow signal 230 during a sleep apnea event. As shown in FIG. 2, the RlP-flow signal 230 looks almost the same as the pneumotach referenceairflow 210 while the nasal cannula signal 220 does not match the pneumotach reference at all times. This may be because the first breath after the apnea may be through the mouth when the patient gasps for air. This first breath and how large it is compared with normal breath may provide significant clinical information about the type of apnea that can affect the choice of treatment. The inventors of the present disclosure have found that, unlike nasal cannula signals, RIP signals may be used to derive this information in a reliable way.

[0060] FIG. 3 illustrates graphs that depict how well the RIP bands measure breathing amplitude compared with nose cannula. As shown in FIG. 3, all the recovery breaths 310 fall well on the reference line using the RIP belts. In contrast, the nose cannula only captures the breaths that are purely happening over the nose, while those where the mouth opens during the recovery breath 310 fall out of line. FIG. 3 also shows that the RIP-flow signal may be tightly correlated with the pneumotach reference, while the cannula tends to be scattered due to mouth breathing. This may be important because the recovery breath amplitude may be a key parameter in determining the endotypes of sleep apnea and other important sleep study data. The RIP signals may thus have a high value for diagnosing sleep disordered breathing.

[0061] The inventors of the present disclosure have also made recent discoveries from the analysis of the RIP signals that increase even further the diagnostic value of RIP. In particular, the inventors of the present disclosure have been focusing on pulling out useful information and data from the RIP signals for all kinds of useful clinical analysis.

[0062] This focus has resulted in a recent discovery of a novel algorithm that is now branded as BodySleep™. This algorithm may use a convolutional neural network (CNN) that has been trained on the RIP signals to derive information regarding the state of the brain during sleep that are by the AASM guidelines traditionally determined from brain signals (EEG). The algorithm may involve classification of sleep into the sleep stages (Wake, NREM and REM) and also can involve detecting cortical arousals, which are when the brain wakes up briefly due to some distraction, such as sleep apnea.

[0063] The arousals may be very important to detect as they may be a strong indicator of different sleep disorders and may be especially important for sleep disordered breathing and sleep apnea, as they contribute to the apnea severity index (AHI). The AHI index is actually the count of three different events: 1) “apnea” (which may be a >90% drop in flow for >10 sec), 2) “hypopnea with desaturation” (which may be a >30% drop in flow for >10 sec, followed by an Oximeter Desaturation of >3%), and 3) “hypopnea with arousal” (which may be a >30% drop in flow for >10 sec, followed by an arousal, which may be an awakening measured as a change in an electroencephalogram (EEG) signal).

[0064] As traditional Home Sleep Apnea Testing (HSAT) does not have EEG measured, it may not deliver a “true” AHI, but an index called REI (Respiratory Event Index). Traditional HSATs include multiple sensors such as a nasal cannula or thermistor. The REI may be the sum of #1 and #2 above without including any #3 events. For this reason, by definition, the REI delivers a systematically lower values that the AHI. In many clinical standards, an HSAT delivering low values of REI is therefore considered “Inconclusive” and should be followed up with an in-lab polysomnography (PSG) sleep study, including EEG arousals and therefore providing a true AHI. As the HSAT is normally much lower cost and more accessible, it may be desirable if HSAT could provide improved data, for example AHI rather than REI.

[0065] Turning to FIG. 4, FIG. 4 illustrates data that shows the capability of the BodySleep™ algorithm to predict arousals from RIP signals. FIG. 4 is derived from a large dataset that includes 643 PSG studies. The signals in the study were auto-scored three times for sleep apnea. The first time, only the HSAT signals (including RIP) were used. The second time included BodySleep™ with arousal detection based on RIP belts, and the third time included full PSG autoscoring including EEG signals as gold standard reference. These studies are originally PSG recordings that had been manually reviewed before the study.

[0066] The values of AHI of 5 and 15 may have direct clinical importance, as they may be used in the clinical process to determine the severity of sleep apnea. For example, an AHI of less than or equal to 5 may be considered low and normally not treated, an AHI in the range of 5 to 15 may be mild and either not treated or treated using alternative methods to CPAP, an AHI in the range of 15 to 30 may be moderate and usually treated with CPAP, and an AHI of greater than 30 may be severe and may need CPAP and special care management.

[0067] The performance of the above discussed algorithm on determining those thresholds are shown in FIG. 4. Based on REI only, 38% of the patients have an REI that is less than 5 that would have measured with AHI of greater than 5 based on a manually scored PSG. The sensitivity when using BodySleep™ diagnostics or autoscored PSG both provided the same sensitivity of 96%, with the BodySleep™ algorithm only misclassifying 4% as having an AHI of less than 5 where the manual PSG classified AHI as greater than 5. For AHI greater than or equal to 15, this was even more dramatic. Based on REI only, 46% of the patients have an REI of less than 15 where the AHI was actually greater than 15 and therefore were miscategorized by the HSAT. Again, autoscored PSG and BodySleep™ performed with similar sensitivity of 89% and 88%.

[0068] This is visualized in the graph 410 with the dark grey dots 412 and light grey dots 414 showing the deviation of the BodySleep™ AHI and HSAT REI respectively compared withthe manually scored PSG-AHI (represented by black line 411). The REI is as expected consistently below the PSG-AHI while the BodySleep™-AHI is distributed around the reference line. The interscorer variability between two humans may be significant and one would expect a similar performance as we see from the BodySleep™-AHI when multiple human scored sleep studies are compared.

[0069] Even if predictions of sleep stages and arousals have been accomplished before based using other signals than RIP, (such as smart watches predicting sleep based on pulse signal), the breakthrough with using BodySleep™ analysis on RIP signal is that it may be very reliable across patient groups, patient types and sleep disorders, which may provide PSG equivalent and conclusive AHI analysis from HSAT at the fraction of the cost of an in-lab PSG. Furthermore, as the BodySleep™ results may only depend on the RIP signals, it may not require a full HSAT study to get those results, a simple measure of only two RIP belts with the appropriate quality is sufficient.

[0070] Accordingly, RIP signals may provide an accurate and reliable alternative to cannula flow signal and may provide a low- value alternative for determining sleep stage and arousal detection. The inventors of the present application have found that there is a demand for a highly scalable measurement technology for measuring RIP during sleep.

[0071] 1.1 The RIP Basics

[0072] RIP technology can be described as the measurement of the inductance of a one-loop- areal-modulated inductor by forming an LC Oscillator and measuring its resonance frequency. Referring to FIG. 5, FIG. 5 illustrates a representation of RIP technology according to some embodiments described herein. The RIP technology may include a RIP belt that includes an inductor 510 as described above. The inductor 510 of FIG. 5 may have a first terminal 512 and a second terminal 514. By adding a fixed capacitor (not shown) across the first terminal 512 and second terminal 514, an ECO resonance circuit may be formed such that for a given LC, the resonance frequency may be determined by the equation f=l / (2*PI*SQRT(L*C)), where f is the resonance frequency, L is the inductance of the inductor 510, and C is the capacitance of the capacitor. The inductor 510 may have a loop diameter D and an inductor diameter d as shown in FIG. 5. The inductance (L) of the inductor 510 may be approximated by the equation: L= popr(D / 2)*(ln((8*D) / d)-2).

[0073] As the RIP belt may encircle a body part that changes its encircled area Ardue to respiration, the D of the formula above changes while the other parameters stay put. For small changes in the Ar(for example, <2% for typical breathing), there is approximately a linear relationship between the changes of L and the Ar. By exciting the LCO and measuringthe resulting resonance frequency f, two signals T and A can be derived, representing the respiratory movements of thorax and abdomen may be derived from RIP belts placed over the thorax and abdomen of a patient, respectively. The signals may be processed for respiratory volume and the derivative respiratory flow.

[0074] For example, FIG. 6 illustrates how one or more RIP belts may be worn by a patient according to some embodiments discussed herein. As shown in FIG. 6, a patient 610 may wear a RIP belt 620 around the patient’s thorax 612, and the patient 610 may wear a RIP belt 620 around the patient’s abdomen 614. In such a way, RIP belts may generate the signals T and A discussed above. The RIP belts 620 may include a stretchable conductor that may fit tightly as a single loop on different patients with elastic force on the encircled body part that is high enough to stay in place and to accurately follow the respiration movements, but low enough to avoid affecting the body area. To illustrate this point, a belt that is too tight may not follow the respiratory movement of a soft belly but instead may dig into the soft belly and therefore may not represent the areal change due to respiration.

[0075] The RIP belt 620 may thus provide an elastic-conductor that encircles a body part one time. The RIP belt 620 may provide such using a wire woven in a waveform shape into an elastic textile (for example, as shown by the wire 622 in FIG. 6). Thus, when placed on a patient, the RIP belt 620 may encircle the body part, for example the thorax or the abdomen, snugly and accurately follow the respiratory change of the area that the RIP belt 620 encircles without affecting the respiration itself.

[0076] The RIP belt 620 may be fine-tuned to provide the high elasticity to fit a range of patient diameters D, with the minimum adjustment of sizes providing fixed and low force on the body. Thus, the RIP belt 620 may be configured to be disposable, as making the RIP belt 620 robust and washable for long term use may hinder these characteristics. The wire 622 may have a low enough diameter to provide comfort and flexibility to the RIP belt 620 while providing good connectivity to the LCO circuit. The wire may eventually be around 0.3Q / m and when woven into the belt, which may end in a total resistance in the range of 0.7Q- 1 ,2Q when manufactured into different sized belts. The wire may have a higher or lower resistance than the above range based on its resistance per length. For example, the wire may have a resistance per length in the range from 0.05 Q / m to 0.7 Q / m, in the range from 0.1 Q / m to 0.6 Q / m, in the range from 0.2 / m to 0.5 Q / m, and / or in the range from 0.3 Q / m to 0.4 Q / m.

[0077] 1.2 The Q of RIP

[0078] The resistance of the whole loop may be of high importance for the quality of the RIP signal, including belts, the connection of the belts to the driving-recorder and the internalconnections within the recorder all the way to the resonator capacitor C. A common measure of quality of an LCO oscillators is Q, where Q is calculated as: Q = (2*PI*f*L / R).

[0079] The Q may thus be the impedance of the RIP belt (L) at the resonance frequency (f), divided by the loop-resistance (R). The higher the Q, the less drive may be required to maintain the oscillation, that is, if the oscillation is started but not driven, it may fade out with time. The higher the Q, the longer the oscillation may take to fade out. A general rule of thumb may be that Q equals the number of periods it takes the oscillation to fade out without a drive. In other words, with Q=l, a continuous drive may be required to keep the oscillation going, but with Q=10, the oscillation may self-oscillates 10 times before disappearing.

[0080] Low Q may not only mean short lived self-oscillation, but also may mean high oscillation phase distortion and as a consequence high noise in the oscillation frequency measure. Low Q therefore may mean low Signal to Noise Ratio (SNR) for the RIP signals.

[0081] RIP signals may be operated typically in the 200kHz range, with typical L in the 3pH range and belts at 1 Ohm resistance. This may mean that the Q = (2*Q*200kHz*3p H) / l Q is only 3.7. For smaller belt sizes, the L may be even lower or all the way down to IpH with Q just around 1. Thus, it may be desirable for the environment of the device and the rest of the circuitry to be exceptionally stable to avoid adding noise and minimizing the effect of the low Q-

[0082] 1.3 The R of RIP

[0083] One parameter that may affect the performance of RIP is the connection / resistance stability. Even if the RIP belt resistance is totally within a range between, for example 0Q and IQ, a change in a fraction of this resistance may cause high noise in the RIP signal. Tests conducted by the inventors of the present disclosure have shown that changes above lOmQ may cause spikes of unacceptable levels in RIP signals.

[0084] This was earlier a sleep-industry wide problem that was previously tackled with strong digital signal filtering. That is until the inventors of the present disclosure invented and patented a RIP Belt connector in the form of a plastic-component that provided a highly reliable connection between the belts and the conducting male-snaps.

[0085] When designing the mechanical connection of RIP products, and especially in a disposable product, the effect of resistance change may thus be considered in detail. For example, the patient may be breathing, which may cause the belts to be pulled mechanically on the RIP Belt termination and connection with the snaps. The connection stability between the belts and the snaps may be ensured by a high-pressure contact between the belt wire and an edge of the RIP snap that flattens the wire out, providing a large-area stable connectionbetween the snap and the belt wire. This has demonstrated to be highly reliable during the sleep studies performed by the inventors of the present disclosure.

[0086] In the case of a disposable product using such a plastic snap, it may be important not only consider the conductance stability between the belt wire and the conductive counterpart in the snap, but also to consider all the combined resistance of the LCO.

[0087] 1.4 RIP Products

[0088] Referring now to FIG. 7, FIG. 7 illustrates an example of a RIP product. As shown in FIG. 7, the RIP product 700 may include a RIP belt module 710 that may include a RIP belt 712, an amplifier 720, a logic comparator 730, and an impulse filter 740. The RIP product 700 may be configured such that the RIP belt module 710 may fit a patient with body parts (e.g., thorax and abdomen) ranging from 30cm to 200cm. The RIP belt module 710 may tolerate 5% areal modulation for less than 120 cm circumference and 2% for greater than 120 cm circumference without distortion or saturation in the signal. The RIP belt module 710 may generate a signal that may have a bandwidth of 0.1-12.5Hz at 25Hz sampling rate, a bandwidth of 0.1-100Hz at 200Hz sampling rate, may provide greater than 50dB SNR at 2Hz bandwidth on a 2% areal modulation, stimulated with a 0.5Hz sine wave movement for any belt size range, and may provide the signal in linear correlation with areal modulation of amplitude between 0.1% and 0.2% with R2greater than 0.98. Additionally, the resonance frequency of the RIP belt module 710 may be in the range of 150kHz to 500kHz depending on the inductance of the RIP belt module 710 and on the value of a capacitor 714 of the RIP belt module 710. Different resonant frequencies may be used in a RIP belt module 710 placed on the abdomen and a RIP belt module 710 placed on the thorax in order to avoid interference between the RIP belts.

[0089] The functionality of the RIP belt module 710 may be tested using a simulator, for example the simulator 800 shown in FIG. 8. FIG. 8 illustrates an example simulator used to test functionality of a RIP belt. As shown in FIG. 8, the simulator 800 may allow a RIP belt 810 of any size to be stretched out into triangles. A motor 820 may be connected to the RIP belt 810 and may be configured to test the functionality of the RIP belt 810 by moving the RIP belt 810 at the point at which the motor 820 is connected to the RIP belt 810. For example, the motor may output sine waves of different frequencies and amplitudes, and may also provide playback of real RIP recordings from patients that may be important in some cases for providing evidence of performance to governmental authorities such as the Food and Drug Administration.

[0090] Returning now to FIG. 7, the RIP belt module 710 may provide an oscillating signal. The oscillating signal may have a resonance frequency that may change due to changes in the inductance of the RIP belt module 710. The RIP belt module 710 may be connected to the amplifier 720 such that the amplifier 720 may output an amplified signal that is an amplified version of the oscillating signal from the RIP belt. The amplifier 720 may be connected to the logic comparator 730 such that the logic comparator 730 may receive the amplified signal from the amplifier 720 and may convert the amplified signal into a square wave that the logic comparator 730 then outputs into the impulse filter 740.

[0091] FIG. 7 also illustrates that the impulse filter 740 may be connected to the RIP belt module 710, the amplifier 720, and the logic comparator 730 such that the impulse filter 740 may output a pulse into the RIP belt module 710 based on the input square wave from the logic comparator 730. This may provide sufficient excitation for the oscillations in the RIP belt module 710 to start and / or continue.

[0092] The RIP product 700 may have the disadvantages of being too complicated, costly, and energy consuming for a disposable electronic circuit. For example, the energy consumption may be in the range of constant 5-10mA.

[0093] 2.0 RIP Devices

[0094] Some significant advantages of some embodiments of the present disclosure may include utilizing low- voltage and high-voltage in the same RIP oscillator feedback loop to save energy, a RIP signal with high quality and high bandwidth, not requiring the use of a high frequency / low frequency clock control, low power wireless transmission of RIP signal data, a low energy consumption by compressing the RIP data before transmission, a compact footprint of RIP device with very small battery, and a RIP device that weighs significantly lighter.

[0095] Turning now to FIG. 9A, FIG. 9A illustrates a high-level diagram of a RIP device according to some embodiments described herein. As shown in FIG. 9A, a RIP device 900 may include an oscillator circuit 910, an amplifier circuit 920, a voltage controlled switch 930, and a low voltage DC source 950.

[0096] According to some particularly advantageous embodiments described herein, the RIP device 900 may operate on low power. Assuming, for example, that the RIP device 900 is powered by a 3V battery, the RIP device 900 may operate at a voltage in the range from 0.01 V to 3V, preferably in the range from 0.05V to 2.75V, preferably in the range from 0.1V to 2.5V, more preferably in the range from 0.15V to 2V, more preferably in the range from 0.2V to 1.5V, more preferably in the range from 0.25 V to IV, more preferably in the rangefrom 0.3V to 0.9V, more preferably in the range from 0.4V to 0.8V, and more preferably in the range from 0.5V to 0.7V. According to some particularly advantageous embodiments, the RIP device 900 may operate at 0.6V. In some embodiments, the battery may have a voltage that is greater than or less than 3V, and the above ranges would then be appropriately scaled.

[0097] According to some embodiments, the oscillator circuit 910 may be any electronic circuit configured to generate a periodic signal. For low-power designs, the oscillator circuit may be a crystal oscillator (for example in a Pierce or Colpitts configuration), a low-power RC relaxation oscillator, a ring oscillator using CMOS inverters, a MEMS-based oscillator, or a digitally controlled oscillator (DCO) integrated into a microcontroller. According to some advantageous embodiments, the oscillator circuit 910 may include an inductor from a RIP sensor connected in series with a capacitor. In the present disclosure, a RIP sensor may refer to any device or circuitry configured to retrieve RIP signals from a patient. For example, the RIP sensor may include an inductor in the form of a RIP belt. The oscillator circuit 910 may thus assist in enabling low power consumption by the RIP device 900 according to some embodiments described herein.

[0098] According to some embodiments, the amplifier circuit 920 may be any circuit or device configured to increase the amplitude of an electrical signal. For example, the amplifier circuit 920 may be a low-power operational amplifier (op- amp) such as a CMOS or JFET- input op-amp, a class-AB or class-D amplifier for efficient power usage, a transistor-based common-emitter or common-source amplifier, a transistor-based amplifier such as a MOSFET or BJT. The amplifier circuit 920 may additionally include capacitors and resistors configured to alter a frequency response of the amplifier circuit 920. Some examples of such embodiments will be described in further detail below.

[0099] According to some embodiments, the voltage controlled switch 930 may be any voltage-controlled device or circuit that is configured to activate and deactivate an electrical connection. For example, the voltage controlled switch 930 may be a metal-oxide- semiconductor field-effect transistor (MOSFET), such as a low-threshold NMOS or PMOS transistor, a junction field-effect transistor (JFET), a bipolar junction transistor (BJT) operating in a switching mode, or a solid-state relay (SSR) designed for low-power applications. The voltage controlled switch 930 may assist in enabling low power consumption, minimal leakage current, and efficient switching characteristics of the RIP device 900 according to some embodiments described herein.

[0100] According to some embodiments, the low voltage DC source 950 may be any device or circuit configured to provide a stable low voltage DC output. For example, the low voltageDC source 950 may be a battery (for example a lithium-ion, coin cell, or alkaline battery), a low-dropout (LDO) voltage regulator, a DC-DC buck converter, a DC-DC converter (which may be a DC-DC step-down converter), a step-down converter, a step-down regulator, a supercapacitor-based power supply, or a USB power source. The low voltage DC source 950 may assist in enabling low power consumption by the RIP device 900 according to some embodiments described herein.

[0101] According to some embodiments, the low voltage DC source 950 may be a step-down regulator and / or a step-down converter that may operate on the same frequency as the oscillator circuit 910. Step-down regulators may include short current pulses which may interfere with signals generated by the oscillator circuit 910. Because of this, the step-down regulator may be locked with the oscillator circuit such that both the step-down regulator and the oscillator circuit 910 operate together in phase and in frequency. This may beneficially allow any interference from the step-down regulator to appear outside of a bandwidth of interest for the RIP device 900. According to some embodiments, the step-down regulator may operate at an integer multiple of the frequency of the oscillator circuit 910 and / or an integer division of that frequency.

[0102] For example, according to some embodiments, the step-down regulator may operate at an integer multiple of the frequency of the oscillator circuit 910 in the range from 1 to 10, preferably in the range from 2 to 9, more preferably in the range from 3 to 8, more preferably in the range from 4 to 7, and / or more preferably in the range from 5 to 6. Additionally or alternatively, the step-down regulator may operate at an integer division of the frequency of the oscillator circuit 910, for example an integer division in the range from 1 / 32 to 1 / 2, preferably in the range from 1 / 16 to 1 / 3, more preferably in the range from 1 / 10 to 1 / 4, more preferably in the range from 1 / 8 to 1 / 5, and / or preferably in the range from 1 / 7 to 1 / 6. According to some particularly advantageous embodiments, the step-down regulator may operate at an integer division of 1 / 16 of the frequency of the oscillator circuit 910.

[0103] Turning now to FIG. 9B, FIG. 9B illustrates a high-level diagram of a RIP device according to some embodiments described herein. The RIP device 905 and the RIP device 900 may have similar embodiments that may include similar components and may enable similar advantages as described herein. As shown in FIG. 9B, a RIP device 905 may include the oscillator circuit 910, the amplifier circuit 920, the voltage controlled switch 930, the low voltage DC source 950, and may additionally include a comparator 960, an offset voltage controller 980, and a microcontroller 970.

[0104] As illustrated in FIG. 9B, the oscillator circuit 910 may be connected to the amplifier circuit 920 and to the voltage controlled switch 930 to form a feedback loop 940. For example, the oscillator circuit 910 may generate an oscillator signal 915 that oscillates at a certain frequency, which may be the resonance frequency of the oscillator circuit 910. The oscillator signal 915 may be fed into the amplifier circuit 920 as an input.

[0105] In some embodiments, the amplifier circuit 920 may generate an amplifier output signal 925 based on the oscillator signal 915 that is fed into the amplifier circuit 920. The amplifier output signal 925 may then be fed into the voltage controlled switch 930 as an input. According to some embodiments, the voltage of the amplifier output signal 925 may be used by the voltage controlled switch 930 to control how much current is fed into the oscillator circuit 910 to compensate for internal losses in the oscillator circuit 910, which is discussed more in detail below. The feedback loop 940 may thus include the oscillator circuit 910, the amplifier circuit 920, and the voltage controlled switch 930.

[0106] FIG. 9B also shows that the amplifier circuit 920 may be connected to the oscillator circuit 910 and may be configured to receive as an input an AC component of the oscillator signal 915 and to output an amplifier output signal 925 based on the AC component of the oscillator signal 915. For example, the oscillator signal 915 may enter an amplifier stage of the amplifier circuit 920 that only amplifies the AC component of the oscillator signal 915. Any DC component of the oscillator signal 915 may have unity gain.

[0107] The amplifier circuit 920 may be DC biased to half of a supply voltage. According to some embodiments, the supply voltage may be provided by a battery, and the amplifier may be DC biased to half of the voltage of the battery. Because the amplifier circuit 920 may be DC biased, the RIP device 905 may run only on the voltage of a battery.

[0108] FIG. 9B also shows that the voltage controlled switch 930 may be connected to the oscillator circuit 910 and to the amplifier circuit 920. In some embodiments, the voltage controlled switch 930 may be configured to receive the amplifier output signal 925 as an input and, when in a closed configuration, to output current to the oscillator circuit 910 based on the received amplifier output signal 925. When in an open configuration, the voltage controlled switch 930 may prevent current flow to the oscillator circuit 910. According to some embodiments discussed in more detail below, the voltage controlled switch 930 may be a MOSFET that may operate in the ohmic region (also synonymously referred to as linear region and triode region) and in the saturation region.

[0109] As mentioned above, the RIP device 905 may include a feedback loop 940 that includes the oscillator circuit 910, the amplifier circuit 920, and the voltage controlled switch930. Because of the feedback loop 940, each component in the feedback loop 940 may operate at the same frequency. Additionally or alternatively, each component in the feedback loop 940 may be synchronized with the oscillator signal 915 and / or with harmonics of the oscillator signal 915. This may beneficially enable the voltage controlled switch 930 to operate at the same frequency as the oscillator circuit 910, which may enable the voltage controlled switch 930 to push current to the oscillator circuit 910 at the resonant frequency of the oscillator circuit 910.

[0110] According to some preferred embodiments, the power loss of the voltage controlled switch 930 can be minimized, as the greatest power loss within the feedback loop may occur within the voltage controlled switch 930. To maintain oscillations within the oscillator circuit 910, the oscillator circuit 910 may require a fixed amount of energy over time. In some embodiments, the voltage controlled switch 930 may provide the amount of energy required by oscillator circuit 910 to maintain oscillations within the oscillator circuit 910.

[0111] FIG. 9B additionally shows that the comparator 960 may be connected to the amplifier circuit 920 and may be configured to receive the amplifier output signal 925. The comparator 960 may convert the amplifier output signal 925 into an output square wave. The output square wave may then be input into a microcontroller 970. Because the output square wave may be based on the oscillations of the oscillator circuit 910 through the amplifier circuit 920, the microcontroller 970 may calculate the resonance frequency of the oscillator circuit 910 based on the frequency of the output square wave. The microcontroller 970 may transmit data based on the output square wave as described below.

[0112] According to some embodiments, the output square wave of the comparator 960 may not be connected to any component of the RIP device 905 other than the microcontroller 970 and thus may not be incorporated in the feedback loop of the oscillator circuit 910. Because the output square wave of the comparator 960 may not be used as feedback to the oscillator circuit 910, the specifications of the comparator 960 may be relaxed. For example, the comparator 960 may have a propagation delay which may be slower, which in turn may enable lower cost components and lower power consumption as compared to other comparators with relatively higher propagation delay.

[0113] FIG. 9B also shows that the offset voltage controller 980 may be configured to provide a DC bias to the amplifier output signal 925 output by the amplifier circuit 920 at the voltage controlled switch 930. According to some embodiments, the offset voltage controller 980 may be any circuit or device configured to adjust or regulate an offset voltage to a signal. For low-power designs, the offset voltage controller 980 may be a digital-to-analog converter(DAC) with a precision reference, a low-power operational amplifier (op-amp) or voltage source with a resistive divider or trimming network, a digitally controlled potentiometer, a low-power bandgap voltage reference, or a feedback-controlled current source.

[0114] According to some embodiments, the offset voltage controller 980 may set a DC reference voltage such that the voltage controlled switch 930 has a maximized power efficiency as will discussed in further detail below.

[0115] According to some embodiments, each component of the RIP device 905 may be configured to fit within a single integrated circuit package. Additionally, only certain components may be configured to fit within a single integrated circuit package. Thus, any combination of the oscillator circuit 910, amplifier circuit 920, voltage controlled switch 930, comparator 960, offset voltage controller 980, and microcontroller 970 may be configured to fit within a single integrated circuit package.

[0116] Referring now to FIG. 10, FIG. 10 illustrates a detailed schematic of a RIP device according to some embodiments. As shown in FIG. 10, the RIP device 905 may include an oscillator circuit 1010, an amplifier circuit 1020, a voltage controlled switch 1030, a comparator 1040, and an offset voltage controller 1080. Each of these components may be similar to the oscillator circuit 910, amplifier circuit 920, voltage controlled switch 930, comparator 960, and offset voltage controller 980, respectively, of the RIP device 905 of FIG. 9B.

[0117] While a particular arrangement of components is shown in FIG. 10 for each of the oscillator circuit 1010, amplifier circuit 1020, voltage controlled switch 1030, comparator 1040, and offset voltage controller 1080, this disclosure is not limited to any one particular arrangement, and instead it will be understood that the particular arrangement of components is shown in FIG. 10, FIG. 10 merely includes exemplary embodiments for each of the oscillator circuit 1010, amplifier circuit 1020, voltage controlled switch 1030, comparator 1040, and offset voltage controller 1080.

[0118] FIG. 10 shows that the oscillator circuit 1010 may be an LC tank circuit that may include an inductor 1012 connected in parallel with one or more capacitors 1014. The inductor 1012 may be part of a RIP sensor that may be connected to one or more electrically conductive terminals 1018 of the oscillator circuit 1010. FIG. 10 also shows that the oscillator circuit 1010 may include a series inductor 1016 connected in series with the inductor 1012 and in parallel to the one or more capacitors 1014. The series inductor 1016 may be a fixed inductor that has a fixed inductance. According to some embodiments, the inductor 1012 may be a RIP belt that may include a single looped wire. According to some embodiments, theoscillator circuit 1010 may generate an oscillator signal that may correspond to the breathing patterns of a patient that may be wearing the RIP belt.

[0119] FIG. 10 also shows that the oscillator circuit 1010 may include a transformer 1060 that may isolate a patient wearing the RIP belt from DC currents found in the RIP device 905. According to some embodiments, the LC tank may be connected to the voltage controlled switch 1030 and the amplifier circuit 1020 through the transformer 1060. While a single transformer is shown in FIG. 10, more than one transformers may be used according to some embodiments. Multiple transformers, for example two transformers, may improve SNR by eliminating noise sources from the switching of other components of the RIP device 1000. Additionally, the transformer 1060 may have a 1:1 winding ratio according to some embodiments.

[0120] Certain embodiments of the oscillator circuit 1010 shown in FIG. 10 will now be described in greater detail with reference to FIG. 11. FIG. 11 illustrates a detailed schematic version of an oscillator circuit according to some embodiments described herein. As shown in FIG. 11, the oscillator circuit 910 may include an inductor 1112 and a series inductor 1116 connected in series with the inductor 1112 and in parallel with the one or more capacitors 1114.

[0121] As discussed above, the inductor 1112 may be a RIP belt that is part of a RIP sensor and that may be connected to one or more electrically conductive terminals 1118. Each RIP belt may have a different size based on the patient which the RIP belt is designed to fit. Because inductance may vary with area enclosed by the RIP belt, the inductance of each RIP belt may vary; the larger the RIP belt may be, the higher inductance it may have, and the smaller the RIP belt may be, the lower inductance it may have.

[0122] The series inductor 1116 may increase the overall inductance of the oscillator circuit 910. With increased overall inductance, the oscillator circuit 910 may exhibit reduced sensitivity to variations in resonance frequency, which variations may result from changes in the shape of the RIP belt as worn by a patient during respiration. The increased inductance may also result in a higher signal-to-noise ratio (SNR) due to a corresponding narrowing of the bandwidth of the oscillator circuit 910. Thus, there may be a tradeoff between SNR and sensitivity to changes in the resonance frequency that may be optimized by selecting the inductance of the series inductor 1116. In some embodiments, the series inductor 1116 may have an inductance of 2.2pH and the inductor 1112 may be a RIP belt that may have an inductance in the range of 0.5pH -7pH. According to some embodiments, the series inductor1116 may have a higher or lower inductance than 2.2pH and may be tuned to optimize the tradeoff between SNR and sensitivity in the resonance frequency.

[0123] For example, according to some embodiments that include a RIP belt as the inductor 1112, the series inductor 1116 may be selected based on the inductance of the inductor 1112 to maintain an optimal tradeoff between SNR and sensitivity to changes in the resonance frequency across RIP belts with differing inductances. As an illustrative example, for a RIP belt with a relatively lower inductance, for example an inductance of less than 2p H, the series inductor 1116 may have a relatively higher inductance, for example an inductance in the range of 2.2p H to 4p H or even a higher inductance than that. For a RIP belt with a relatively higher inductance, for example an inductance in the range of 2.2p H to 7pH, the series inductor 1116 may have a lower inductance, for example an inductance in the range of Op H to 2.2pH.

[0124] According to some embodiments, the series inductor 1116 may have an inductance in the range from Op H to 7p H, preferably in the range from O.lpH to 7p H, IpH to 6p H, preferably in the range from 2p H to 5p H, preferably in the range from 2p H to 2.5p H, and preferably in the range from 2.5p H to 4p H. According to some particularly advantageous embodiments, the series inductor has an inductance of 2.2p H.

[0125] The above ranges and values associated with the series inductor 1116 and RIP belt are provided merely to illustrate how the inductance of the series inductor 1116 may be chosen to optimize the tradeoff between SNR and sensitivity to changes in the resonance frequency and that the present disclosure is not limited to those ranges. According to some embodiments, the series inductor 1116 may have a variable inductance that may be selectable within any of the above ranges in order to adapt to different sized RIP belts.

[0126] According to some embodiments, the RIP belt may provide a high enough inductance that the series inductor 1116 may be removed from the oscillator circuit 910. According to some embodiments, there may be more than one series inductor 1116 that may be selectable based on the inductance of the inductor 1112 to maintain the optimized tradeoff between SNR and sensitivity to changes in the resonance frequency. Thus, the series inductor 1116 may enable an optimized tradeoff between SNR and sensitivity to changes in the resonance frequency.

[0127] Referring back to FIG. 10, FIG. 10 shows that the amplifier circuit 1020 may be connected to the oscillator circuit 1010, the comparator 1040, the voltage controlled switch 1030, and the offset voltage controller 1080. According to some embodiments, the amplifier circuit 1020 may be tuned to other components of the RIP device 905. For example, theoscillator circuit 1010 may generate an oscillator signal that may have frequencies between 200kHz and 500kHz. As another example, the phase angle at frequencies between 200kHz and 500kHz may be multiples of 360 degrees.

[0128] Certain embodiments of the amplifier circuit 1020 shown in FIG. 10 will now be described in greater detail with reference to FIGS. 12 and 13. FIG. 12 illustrates a detailed schematic version of an amplifier circuit according to some embodiments described herein. As shown in FIG. 12, the amplifier circuit 1200 may include an amplifier 1210, one or more resistors 1220, and one or more capacitors 1230. As illustrated in FIG. 12, the one or more resistors 1220 and one or more capacitors 1230 may be arranged and selected such that they tune the poles and zeros of the amplifier circuit 1200 to shape the frequency response of the amplifier circuit 1200.

[0129] According to some embodiments, the amplifier circuit 1020 may be connected to a load switch 1240 that may turn the amplifier circuit 1020 on and / or off. When the amplifier circuit 1020 may be off, the RIP device 1000 may not consume any power. Thus, according to some embodiments, the load switch may enable a lower power consumption for the RIP device 1000.

[0130] Turning to FIG. 13, FIG. 13 illustrates a bode plot of an amplifier circuit according to some embodiments described herein. As shown in FIG. 13, the amplifier circuit 1200 may have a frequency response illustrated by amplifier frequency response trace 1310 that may amplify signals that have a frequency in the range of 200kHz to 500kHz. Additionally, FIG. 13 shows that for signals in the range of 200kHz to 500kHz, the amplifier may have a phase angle of 360 degrees. Thus, the phase of the signal input into the amplifier circuit 1020 may not be changed by the amplifier circuit 1020.

[0131] According to some embodiments, the RIP signals may fall into a particular bandwidth of interest for taking RIP measurements. The amplifier circuit 1020 may amplify only those signals that fall into the bandwidth of interest for taking RIP measurements. As an illustrative example, the bandwidth of interest for taking RIP measurements may be in the range from 50kHz to 800kHz, preferably in the range from 100kHz to 700kHz, more preferably in the range from 150kHz to 600kHz, more preferably in the range from 200kHz to 500kHz, more preferably in the range from 250kHz to 400kHz, and more preferably in the range from 300kHz to 350kHz.

[0132] The above ranges of bandwidths may be considered an operating frequency range of the amplifier circuit 1020 and / or the oscillator circuit 1010 and / or the RIP device 1000. The amplifier circuit may amplify signals within any of the above ranges and may attenuatesignals that fall outside of any of the above ranges, which may beneficially allow for higher fidelity RIP signal measurements.

[0133] FIG. 13 additionally shows that the amplifier circuit 1020 may be tuned such that a DC-bias voltage may have the response shown by DC-bias voltage response trace 1320. As shown in FIG. 13, the DC-bias voltage may have a response that is always dampened. This may beneficially filter out unwanted frequencies from a power supply, for example a battery as discussed above.

[0134] Returning to FIG. 10, FIG. 10 shows that the voltage controlled switch 1030 may be connected to the oscillator circuit 1010, the amplifier circuit 1020, and the offset voltage controller 1080. According to some embodiments, there are no components between the voltage controlled switch 1030 and the oscillator circuit 1010 other than the connection between the two. Including a component between the voltage controlled switch 1030 and the oscillator circuit 1010 such as a resistor may create additional voltage drop, resulting in higher power loss and decreased efficiency of the RIP device 905.

[0135] Certain embodiments of the voltage controlled switch 1030 shown in FIG. 10 will now be described in greater detail with reference to FIG. 14. FIG. 14 illustrates a detailed schematic version of a voltage controlled switch according to some embodiments described herein. As shown in FIG. 14, the voltage controlled switch 1400 may include a MOSFET 1410, a current limiting resistor 1420, and a low voltage DC source 1430. The low voltage DC source 1430 may be similar to the low voltage DC source 950 of FIGS. 9 A and 9B. The MOSFET 1410 may have a source, a drain, and a gate.

[0136] In some embodiments, the MOSFET 1410 may operate primarily in the ohmic region while it is conducting current. In this region, the MOSFET 1410 may act as a voltage controlled switch, and thus the voltage controlled switch 1400 may include the MOSFET 1410. The MOSFET 1410 may be configured such that the AC voltage on the gate is the amplifier output signal 925 discussed above. The MOSFET 1410 may have an optimal gate to source voltage that may be tuned for a specific MOSFET chosen in the particular embodiment. This gate to source voltage may be set by the offset voltage controller 1080 as described in further detail below.

[0137] As discussed above, the amplifier output signal 925 may have a frequency that is the same frequency as the oscillator signal 915. Thus, the MOSFET 1410 may provide current to the oscillator circuit at the oscillator circuit’s resonance frequency. This may beneficially eliminate harmonic frequencies which otherwise may be present if the MOSFET 1410 were operating in the saturation region with a typical square wave or other fast switching signals.

[0138] FIG. 14 also illustrates that the current limiting resistor 1420 may be attached to the drain of the MOSFET 1410. The current limiting resistor 1420 may constrain the maximum current flow through the MOSFET 1410. FIG. 14 also shows that there may be a low voltage DC source 1430 disposed on the other side of the current limiting resistor 1420 from the MOSFET 1410 from which current may be drawn. According to some embodiments, the voltage of the low voltage DC source 1430 may be 0.6V, which may be less voltage than a battery used to power the RIP device as described above.

[0139] According to some embodiments, the voltage of the battery may be 3V, and the voltage from the battery may be stepped down using a DC-DC converter (or a step-down converter) to 0.6V for use by the voltage controlled switch 1400. The voltage of the battery may be stepped down from the voltage of the battery to a lower voltage level. For example, a 3V battery may be stepped down to 0.5V, 0.4V, 0.3V, 0.2V, 0.1V, or even lower, as doing so may reduce power consumption even further. The 3V battery may also be stepped down to any voltage in the range from 1.5V to 0V. In some embodiments, the 3V battery may be stepped down to any voltage lower than 3 V.

[0140] According to some embodiments, the voltage from the battery may be stepped down to a voltage in the range from 0.05V to 3V, preferably in the range from 0.1V to 2.5V, more preferably in the range from 0.15V to 2V, more preferably in the range from 0.2V to 1.5V, more preferably in the range from 0.25 V to IV, more preferably in the range from 0.3V to 0.9V, more preferably in the range from 0.4V to 0.8V, and more preferably in the range from 0.5V to 0.7V. According to some particularly advantageous embodiments, the voltage form the battery may be stepped down to 0.6V.

[0141] The low voltage DC source 1430, and / or the low voltage DC source 950, may thus be a battery whose voltage is stepped down using a DC-DC converter to the proper level for the oscillator circuit 1010 to operate at low power. Because the low voltage DC source 1430 may have a lower voltage than the voltage of a battery used to power the RIP device 905, the voltage controlled switch 1400 may consume less power than if the RIP device 905 were powered directly from the battery. Thus, the low voltage DC source 1430 and / or the low voltage DC source 950 may provide be a DC source that is lower than a DC source of a battery, which may, according to some embodiments, enable the RIP device 905 or the RIP device 900 to operate at low power. Additionally, such a low voltage DC source 1430 and / or the low voltage DC source 950 may thus be referred to as an energy preserving power source.

[0142] Returning to FIG. 10, the interaction between the oscillator circuit 1010 and the voltage controlled switch 1030 according to some embodiments will now be discussed withreference to FIGS. 10, 14, 15, and 16. FIG. 15 shows a simulation of current through a voltage controlled switch according to some embodiments described herein. As shown in FIG. 15, the current through the voltage controlled switch 1030 may include four distinct stages: stage one 1510, stage two 1520, stage three 1530, and stage four 1540. FIG. 15 also illustrates a current trace 1550, a gate signal trace 1560, and an oscillator signal trace 1570.

[0143] In stage one 1510, the inductor 1012 of the oscillator circuit 1010 may be fully charged and the one or more capacitors 1014 of the oscillator circuit 1010 may have no energy. During stage one 1510, the voltage controlled switch 1030 may start conducting current as shown by the uptick during this stage in the current trace 1550. For example, the gate voltage on the MOSFET 1410 may increase enough such that the MOSFET 1410 may start conducting and pushing current into the one or more capacitors 1014 through the transformer 1060.

[0144] In stage two 1520, all the energy may be stored in the one or more capacitors 1014 and the one or more capacitors 1014 may begin to discharge its energy back into the inductor 1012. During stage two 1520, the voltage controlled switch 1030 may still be feeding current into the LC tank through the transformer 1060, but in this stage, the current from the voltage controlled switch 1030 may now be going into the inductor 1012.

[0145] In stage three 1530 the voltage controlled switch 1030 may stop conducting current. For example, the gate voltage on the MOSFET 1410 may decrease enough such that the MOSFET 1410 stops conducting current, shown by the downtick in the current trace 1550 during stage three 1530. In this stage, the inductor 1012 may begin charging the one or more capacitors 1514 by discharging its current in the opposite direction from in stage one 1510.

[0146] In stage four 1540, the voltage controlled switch 1030 continues to not conduct current. For example, the gate voltage on the MOSFET 1410 may continue to be sufficiently low such that the MOSFET 1410 does not conduct current. Additionally, during stage four 1540, the one or more capacitors 1014 may begin discharging its energy into the inductor in the opposite direction from in stage two 1520. From stage four 1540, the circuit may then return to stage one 1510, and a cycle including each stage may repeat until the RIP device 905 gets turned off.

[0147] Accordingly, the voltage controlled switch 1030 may only apply current at the time when current flowing from the transformer 1060 into the LC tank may not be actively working against the current flowing between the inductor 1012 and the one or more capacitors 1014.

[0148] Referring now to FIG. 16, FIG. 16 illustrates a depiction of the relative amount of time that a MOSFET, for example the MOSFET 1410 shown in FIG. 14, remains in each operating mode over varying inductances according to some embodiments described herein. As shown in FIG. 16, the MOSFET 1410 may operate in three operating regions. For each inductance, the topmost section indicates the percentage of the time that the MOSFET 1410 is operating in the saturation region, the middle section indicates the percentage of the time that the MOSFET 1410 is operating in the ohmic or linear region, and the bottom section indicates the percentage of the time that the MOSFET 1410 is operating in the cut off region.

[0149] As shown in FIG. 16, the MOSFET 1410, when it is not in the cut off region, spends a greater percentage of time operating in the ohmic or linear region than in the saturation region across all inductances. Thus, according to some embodiments, the MOSFET 1410 may be configured to operate primarily in the ohmic region when it is conducting current. Because of this, the MOSFET 1410 may eliminate harmonic frequencies which would otherwise be present if the MOSFET 1410 were used in the exclusively in the saturation region with a typical square wave or other fast switching signals.

[0150] Returning to FIG. 10, FIG. 10 shows that the offset voltage controller 1080 may be connected to the voltage controlled switch 1030 and to the amplifier circuit 1020. Certain embodiments of the offset voltage controller 1080 shown in FIG. 10 will now be described in greater detail with reference to FIG. 17. FIG. 17 illustrates a detailed schematic version of an offset voltage controller according to some embodiments described herein. As shown in FIG. 17, the offset voltage controller 1700 may include a plurality of resistors 1710 and one or more switches 1720.

[0151] FIG. 17 shows that the plurality of resistors 1710 may be arranged such that a plurality of voltage dividers 1730 may be formed. Each switch 1720 may be connected to individual voltage dividers in the plurality of voltage dividers 1730 such that the switches 1720 may be used to turn on or off the respective voltage divider in the plurality of voltage dividers 1730 to which the respective switch 1720 is attached. According to some embodiments, a microcontroller (not shown) may activate or deactivate each switch 1720 by providing an ON or OFF signal to the gate of each switch 1720, illustrated in FIG. 17 by the plurality of input traces 1740. Thus, the offset voltage controller 1700 may provide a selectable DC bias at its output, illustrated in FIG. 17 as the offset voltage controller output 1750. According to some embodiments, the offset voltage controller output 1750 may lead to a voltage controlled switch, for example the voltage controlled switch 1030 of FIG. 10 or to the gate of the MOSFET 1410 of FIG. 14.

[0152] As an illustrative, non-limiting example in which the voltage controlled switch 1030 of FIG. 10 includes the MOSFET 1410 of FIG. 14, it may be desirable for the offset voltage controller 1700 to provide one or more DC biases to account for variance in optimal gate threshold voltages across different MOSFETs due to manufacturing or other processes. In order to account for this variance, the offset voltage controller 1080 may bias the DC voltage at the gate of the MOSFET 1410 such that the gate voltage is at or below, for example at least lOOmv below, an optimal gate threshold voltage of the MOSFET 1410. Doing so may beneficially reduce leakage current while the MOSFET 1410 is operating in the cut off region, which may improve the power efficiency of the MOSFET 1410.

[0153] For example, according to some embodiments, the offset voltage controller 1080 may provide four selectable DC bias voltages, for example 0.79V, 0.64V, 0.45V, and 0.37V and / or any DC voltage in the range from 0.01V to 2V. While these specific values are disclosed herein, the disclosure is not limited to those specific DC bias voltages. Instead, as discussed above, the offset voltage controller 1080 may provide a selectable DC bias to the voltage controlled switch 1030 such that the voltage controlled switch 1030 has improved power efficiency. For example, the DC bias voltages may be in a range from 0V to 1.5V, preferably in the range from 0.2V to IV, preferably in the range from 0.3V to 0.9V, preferably in the range from 0.4V to 0.8V, preferably in the range from preferably in the range from 0.5V to 0.7V. According to some embodiments, The DC bias voltages may be selected from any voltage within the above ranges such that the voltage controlled switch 1030 has improved power efficiency and reliability across specific implementations of the voltage controlled switch 1030.

[0154] Returning to FIG. 10, FIG. 10 shows that the RIP device 905 may include a kick circuit 1070. The kick circuit 1070 may provide a sufficient amount of current to the oscillator circuit 1010 to assist the oscillator circuit 1010 in beginning to oscillate. In such a way, the kick circuit 1070 may kick the oscillator circuit 1010. In example embodiments similar to those described above with reference to FIGS. 15 and 17, the amount of current provided by the kick circuit 1070 and the timing of that kick may depend on the gate voltage of the MOSFET 1410 and a DC bias applied by the offset voltage controller 1080. For example, if the DC bias applied by the offset voltage controller 1080 is less than a gate threshold voltage of the MOSFET 1410, then the kick circuit 1070 may kick the oscillator circuit 1010 in order to begin oscillation within the oscillator circuit 1010.

[0155] Turning now to FIGS. 18A and 18B, FIGS. 18A and 18B illustrates a method of reducing the amount of data streamed over a wireless connection by encoding a signal with alarge DC component and a small AC component according to some embodiments described herein. More specifically, FIG. 18A illustrates a method of encoding data to be streamed over a wireless connection, for example a Bluetooth connection, and FIG. 18B illustrates a method of decoding data after it has been streamed over a wireless connection, for example a Bluetooth connection.

[0156] According to some embodiments, a RIP device may capture a signal, for example a RIP signal, that may include a human breathing signal while the human is asleep that may have a frequency within 1Hz. The RIP device may be similar to the RIP device described above in relation to FIGS. 9A-17 and below in relation to FIGS. 19-26B. The RIP signal may be sampled at 200Hz, which may capture high frequency details embedded in the signal, for example electrocardiogram (EKG) details. According to some embodiments, the RIP signal may have a large DC component that the human breathing signal rides on.

[0157] According to some embodiments, the RIP device may be configured to transmit data from the RIP device over a wireless connection. For example, the RIP device may include a computer system that includes computer hardware and / or storage that may have stored thereon computer executable instructions which, when executed by one or more processors of the computer system, configure the computer system to store samples taken of the RIP signal as integers of a fixed bit size into computer storage and to transmit the stored samples over a wireless connection, for example a Bluetooth connection.

[0158] In some embodiments, transmitting a higher bit integer, for example a 32 bit integer, over a Bluetooth connection may consume a larger amount of power than transmitting a lower bit integer, for example an 8 bit integer. According to some embodiments, the RIP device may be configured to perform a method of encoding and / or compressing one or more samples from being stored as higher bit integers into lower bit integers in order to reduce the amount of power it may take to transmit the sample. For example, the RIP device may be configured to compress 32 bit integers into 8 bit integers. Doing so may allow some embodiments described herein to operate at low power, for example at 600mV.

[0159] According to some embodiments, the RIP device may include a computer system that includes computer hardware and / or storage that may have stored thereon computer executable instructions which, when executed by one or more processors of the computer system, configure the computer system to perform a method of encoding and / or compressing one or more samples from being stored as higher bit integers into lower bit integers in order to reduce the amount of power it may take to transmit the sample.

[0160] According to some embodiments, the RIP device may encode the data with the method 1800 shown in FIG. 18A. For example, step 1810 may include collecting a sample S of data from the RIP signal. S may be stored as a 128 bit integer, a 64 bit integer, a 32 bit integer, a 16 bit integer, an 8 bit integer, a 4 bit integer, or a 2 bit integer in step 1810. For illustrative purposes, S may be a stored as a 32 bit integer in step 1810. Step 1820 may include calculating the delta (D), which may be accomplished through the equation D=S-Sref- Sref may be an earlier collected sample S. thus, D may represent the difference between S and Sref- Step 1830 may include checking if D is greater than or equal to -64 and if D is less than or equal to 63. This check may determine whether D is small enough to be stored in 8 bits of data. According to some embodiments, D is checked whether D is small enough to be stored in any number of bits of data in the range from 1 bit to 31 bits, preferably in the range from 2 bits to 16 bits, more preferably in the range from 4 bits to 8 bits. According to some particularly advantageous embodiments, the D is checked whether D is small enough to be stored in 8 bits. According to some embodiments, D is checked whether D is small enough to be stored in any number of bits smaller than the number of bits in which Sref is stored.

[0161] If step 1830 evaluates to no, then D may not be small enough to be stored in 8 bits of data, and instead S must be sent as a new Sref. This may be done as shown in step 1840, step 1850, and step 1860. In step 1840, S may be bit shifted by one bit to the left. Step 1850 may include setting the least significant bit (LSB) of S to binary one, and step 1860 may include sending S as 32-bit data as a new Sref over a wireless connection. Because the LSB may be set to binary one, this may indicate that the S is being sent as a new Sref when S is being decoded.

[0162] If step 1830 evaluates to yes, then D may be small enough to be stored in 8 bits of data, and so D may be sent according to step 1870, 1880, and 1890. Step 1870 may include bit shifting D left by one bits. Step 1880 may include clearing the LSB of D by setting the LSB to binary zero, and step 1890 may include sending D as 8-bit data over a wireless connection. After either step 1860 or 1890, the method 1800 may repeat in a cycle for all data until the RIP device is powered down.

[0163] According to some embodiments, encoded data sent over a wireless connection by the RIP device may be decoded according to the method 1805 shown in FIG. 18B. For example, step 1815 may include reading a byte (Bo) sent over a wireless connection by the RIP device 905. Step 1825 may include checking whether the LSB is set which may determine if the byte is meant to be interpreted as a delta (D) or as a new Sref.

[0164] If the LSB is not set, then Bo may include only D as discussed above. Thus, step 1835 may include bit shifting Bo to the right by one bit. Step 1845 may include adding the current Sref to Bo and storing the result (Sstored) in computer storage.

[0165] If the LSB is set, then the data may include a new Sref. Thus, step 1855 may include reading the next 3 bytes into Sref. Step 1865 may include calculating the new Sref by using the equation new Sref = Bo + Sref * 256. Multiplying Sref by 256 may align all of the bits in the proper order. Step 1075 may include bit shifting Sref to the right by one bit, and step 1885 may include storing the new Sref as the next sample Sref- After either step 1845 or 1885, the method 1805 may repeat in a cycle for all data until the RIP device 905 is powered down.

[0166] Because the method 1800 may encode the samples as a delta for a large proportion of the data, the method 1800 may beneficially reduce the amount of power consumed in transmitting the data. For example, if 32 bits are selected for Sref, and D is selected to be 8 bits, then the method 1800 may improve the efficiency of the RIP device 100 by only sending on average just over 8 bits of data per sample.

[0167] To illustrate this, the below data table illustrates data from an experiment performed by the inventors of the present disclosure. In the experiment, RIP belt signals from a few recordings were encoded according to one embodiment of the method 1800, and each RIP belt’s average bitrate was calculated over the recording duration. As shown in the table below, six of the recordings were with a human patient (an “Individual”) wearing a medium (size “M”) RIP belt on the abdomen (“Abdomen”) and a medium (size “M”) RIP belt on the thorax (“Thorax”), while the Pediatric (size “P”) and extra-large (size “XL”) belts were taken from much shorter recordings where a simulator (the “Simulator”), for example the simulator 800 of FIG. 8, was used to excite the signals. Upon decoding using an embodiment of the method 1805, the signals were verified that the encode-decode process was lossless.

[0168] As shown in the above table, the average bitrate for both the Abdomen and Thorax RIP belts was in the range from 8.0067 bit / sample to 8.3405 bit / sample. As this data is based on a real-world experiment, the theoretical bit rates may be different than the data shown. For example, the bitrate may be in the range from 8.000000001 bit / sample to 8.4 bit / sample, preferably in the range from 8.00001 bit / sample to 8.3 bit / sample, more preferably in the range from 8.001 bit / sample to 8.2 bit / sample, more preferably in the range from 8.01 bit / sample to 8.15 bit / sample, and more preferably in the range from 8.05 to 8.1 bit / sample.

[0169] As discussed above, the RIP device may operate on low power. According to some embodiments, the RIP device may be configured to implement the method 1800 and / or the method 1805. The method 1800 and 1805, when implemented by the RIP device according to some embodiments, may beneficially allow the RIP device to operate at the low power or within the constraints of the low power. For example, by encoding a majority of the samples as deltas according to method 1800, the RIP device 900 may consume less power in transmitting the samples. For example, the RIP device 900 may encode more than 50%, preferably more than 60%, more preferably more than 70%, more preferably more than 80%, more preferably more than 90%, more preferably more than 95%, and more preferably more than 99% of the samples as deltas.

[0170] The method 1800 and the method 1805 may be performed with S stored in any bit size and D stored in any smaller bit size. For example, the aligning the bits performed in step 1865 may be performed for any number of bits by adjusting the value from 256 to the proper power of 2 such that the bits become aligned. Additionally, upon checking whether D is small enough in step 1830, the proper power of 2 may be used to make such a check. For example, if D were selected to be 7 bits, then it would be checked whether D is greater than -32 and less than 31.

[0171] The bit shifting steps (step 1840, step 1870, step 1835, and step 1875) may not be performed as part of the method 1800 and the method 1805, as applicable, in embodiments that do not use the LSB to determine whether the sample is an Sref or a D.

[0172] Turning now to FIG. 19, FIG. 19 illustrates a high-level diagram of a RIP device according to some embodiments described herein. FIG. 19 shows that the RIP device 1900 may include an oscillator circuit 1910, a comparator circuit 1920, a filter circuit 1930, and a reference voltage circuit 1940. FIG. 19 additionally shows that the oscillator circuit 1910 may be connected to the comparator circuit 1920, that the comparator circuit 1920 may be connected to the filter circuit 1930, and that the filter circuit 1930 may be connected to the oscillator circuit 1910. The reference voltage circuit may be connected to the comparator circuit 1920.

[0173] Certain embodiments of the RIP device 1900 will now be described in greater detail with reference to FIG. 20. FIG. 20 illustrates a detailed schematic of a RIP device according to some embodiments described herein. For example, the RIP device 2000 may include a simplified one-stage Colpitts LC oscillator. The RIP device 2000 may thus include an oscillator circuit 2010, a comparator circuit 2020, a filter circuit 2030, and a reference voltage circuit 2040. FIG. 20 shows that the oscillator circuit 2010 may include a Colpitts oscillator including an inductor 2012, a first capacitor 2014, and a second capacitor 2016. The inductor 2012 may be connected in series the first capacitor 2014 and in parallel with the second capacitor 2016. The inductor 2012 may be a RIP belt as discussed above which may have a resistance symbolized by the resistor 2013.

[0174] FIG. 20 also shows that a series inductor 2018 may optionally be included in series with the inductor 2012. The series inductor 2018 may enable similar benefits as described above relating to the series inductor 1116 of FIG. 11. To illustrate these advantages, FIG. 21 A illustrates a simulation of a RIP device without a series inductor according to some embodiments described herein, and FIG. 2 IB illustrates a simulation of a RIP device with a series inductor according to some embodiments described herein. For example, if the RIP device 2000 does not have the series inductor 2018, then the current through the resistor 2050 that may be connected in series with and in between the output of the comparator circuit 2020 and the input of the filter circuit 2030 may be illustrated by current trace 2110, while the oscillations of the oscillator circuit 2010 may be illustrated by oscillator trace 2120. As shown in FIG. 21 A, without the series inductor, the current peaks at the switch may approach as high as 25 mA, which may be problematic for many high-speed / low-cost comparators.Additionally, without the series inductor 2018, the RIP device 1900 may use between 5- 10mA on average, which may be too high for low power embodiments.

[0175] With the inclusion of the series inductor 2018, the Q of the loop increases as discussed above. With the series inductor 2018, the current through resistor 2050 may be illustrated byimproved current trace 2115, and the oscillations of the oscillator circuit may be illustrated by improved oscillator trace 2125. While adding the series inductor 2018 may increase the Q of the oscillator circuit 2010, doing so may also reduce the frequency sensitivity with the modulation of the RIP belt as described above. However, doing so may also beneficially reduce the power consumed by the circuit as shown in FIG. 2 IB, where the peak impulse may be lowered to only 2mA.

[0176] Returning to FIG. 20, FIG. 20 additionally shows that the comparator circuit 2020 may receive an input from the oscillator circuit 2010 at its negative input and another input from the reference voltage circuit 2040 at its positive input. The comparator circuit 2020 may be configured to compare both inputs and provide an output square wave based on the inputs.

[0177] FIG. 20 also shows that the filter circuit 2030 may include a resistor 2032 and a capacitor 2034 connected in parallel. This may shape the signal coming from the output of the comparator circuit 2020 such that the output of the filter circuit 2030 may kick the oscillator circuit 2010 in a similar manner as described above by providing enough excitement to the oscillator circuit 2010 to begin and / or continue oscillations within the oscillator circuit 2010.

[0178] FIG. 20 additionally shows that a reference voltage may be applied to a positive terminal of the comparator circuit 2020. The reference voltage may be selected based on the voltage of a voltage source 2042 and may be selected using a voltage divider formed by one or more resistors 2044.

[0179] Turning now to FIG. 22, FIG. 22 illustrates a high-level diagram of a RIP device according to some embodiments described herein. FIG. 22 shows that the RIP device 2200 may include a hybrid buck circuit 2240, an oscillator circuit 2210, a comparator circuit 2220, a filter circuit 2230, and a power supply 2250. FIG. 22 shows that the hybrid buck circuit 2240 may be connected to the oscillator circuit 2210, that the oscillator circuit 2210 may be connected to the comparator circuit 2220, that the comparator circuit 2220 may be connected to the filter circuit 2230, that the filter circuit 2230 may be connected to the hybrid buck circuit 2240, and that the power supply may be connected to both the hybrid buck circuit 2240.

[0180] For RIP, the oscillator circuit 2210 may only need to be measured in the tens of mV in amplitude to be practical. The timing of the oscillation crossover (from negative to positive or from positive to negative voltage) may be accurately detected for the triggering of the excitement. For example, too low signal amplitude into the comparator circuit 2220 may cause jittering in the triggering- time of the comparator circuit 2220 which may result inincreased noise and lower signal quality. Signals that are close to lOOmV may be practical both electrically for quality excitation of the oscillations and may be low enough for patient safety reasons for signals deployed to a medical device galvanically connected to the human body.

[0181] As an illustrative example, for the oscillations within the oscillator circuit 2210, which may for example operate at an amplitude of lOOmV with a Q of 2, an equivalent of 50mV of signal amplitude may need to be added to the capacitor voltage for every period due to the loss in the LC resistance. Embodiments of the present disclosure may all run on a 3 V power supply that may then be dropped down to the lOOmV range, which may mean that there is over a 95% loss in driving energy in the circuits around the oscillator circuit 2210 rather than that energy being conserved by the capacitor in the oscillator circuit 2210.

[0182] In order to improve the power efficiency of the circuit, the hybrid buck circuit 2240 may be included in the RIP device 2200. Certain embodiments of the RIP device 2200 will now be described in greater detail with reference to FIG. 23A. FIG. 23A illustrates a detailed schematic of a RIP device according to some embodiments described herein. FIG. 23A shows that a RIP device 2300 may include an oscillator circuit 2310, a comparator circuit 2320, a filter circuit 2330, a hybrid buck circuit 2340, and a power supply 2350. Each component may be connected in a similar manner as shown and described above in relation to FIG. 22.

[0183] FIG. 23A shows that the hybrid buck circuit 2340 may include a power inductor 2342, a switch 2344, and a diode 2346. Similar to embodiments described above, the oscillator circuit 2310 may have a resonance frequency at which each circuit in the RIP device 2300 operates. For example, the frequency of the hybrid buck circuit 2340 may be synchronized with a resonance frequency of the oscillator circuit 2310 through the comparator circuit 2320. According to some embodiments, the output of the comparator circuit 2320 may be connected to the switch 2344 such that when the output of the comparator circuit 2320 is logical high, the switch 2344 may be activated and begin conducting current, and when the output of the comparator circuit 2320 is low, the switch 2344 may be deactivated and cease to conduct current.

[0184] The diode 2346 may be connected to ground and in between the switch 2344 and the power inductor 2342 such that current may only flow from ground through the diode and not from the switch 2344 and the power inductor 2342 to ground. Thus, when the switch 2344 is activated, current may be pulled from the power supply 2350 into the power inductor 2342. When the switch 2344 is deactivated, current may continue to flow because of the powerinductor 2342 from ground, through the diode 2346, and into the oscillator circuit 2310 until the power inductor 2342 loses all of its energy.

[0185] According to some embodiments, the hybrid buck circuit 2340 may operate in synchrony with and / or be synchronized with the oscillator circuit 2310. This may enable the charge delivered from the hybrid buck circuit 2340 to the oscillator circuit 2310 to be delivered at the correct time, for example the time for driving continuous oscillations within the oscillator circuit 2310 without working against the oscillations within the oscillator circuit 2310. The hybrid buck circuit 2340 may have a shorter duty cycle than a duty cycle of the oscillator circuit 2310. For example, the duty cycle of the hybrid buck circuit may be half that of the oscillator circuit 2310.

[0186] According to some embodiments, the hybrid buck circuit 2340 may operate at an integer multiple of the frequency of the oscillator circuit 2310 and / or an integer division of that frequency. This may beneficially cause any interference noise between the hybrid buck circuit 2340 and the oscillator circuit 2310 to be outside of a bandwidth of interest for measuring the oscillations of the oscillator circuit 2310, for example when measuring RIP signals generated by the oscillator circuit 2310.

[0187] For example, according to some embodiments, the hybrid buck circuit 2340 may operate at an integer multiple of the frequency of the oscillator circuit 2310 in the range from 1 to 10, preferably in the range from 2 to 9, more preferably in the range from 3 to 8, more preferably in the range from 4 to 7, and / or more preferably in the range from 5 to 6. Additionally or alternatively, the step-down regulator may operate at an integer division of the frequency of the oscillator circuit 2310, for example an integer division in the range from 1 / 32 to 1 / 2, preferably in the range from 1 / 16 to 1 / 3, more preferably in the range from 1 / 10 to 1 / 4, more preferably in the range from 1 / 8 to 1 / 5, and / or preferably in the range from 1 / 7 to 1 / 6. According to some particularly advantageous embodiments, the step-down regulator may operate at an integer division of 1 / 16 of the frequency of the oscillator circuit 2310.

[0188] Referring now to FIG. 23B, FIG. 23B illustrates the detailed schematic of the RIP device shown in FIG. 23 A with additional components according to some embodiments described herein. As shown in FIG. 23B, in a RIP device 2305, according to some embodiments, the integer division discussed above may be created by a counter circuit 2390. The counter circuit 2390 may have an output based on the output of the comparator circuit 2320 by receiving the output of the comparator circuit 2320 as an input. The counter circuit 2390 may be any circuit or device that is configured to create an integer division of the frequency of the oscillator circuit 2310, for example a logic gate counter. According to someembodiments, the power inductor 2342 may be connected to the oscillator circuit 2310 over one or more isolating capacitors 2380 such that the power inductor 2342 may provide charge to the one or more isolating capacitors 2380 instead of directly to the oscillator circuit 2310. The oscillator circuit 2310 may, according to some embodiments, receive power from the one or more isolating capacitors 2380 instead of directly from the power inductor 2342. This may beneficially minimize potential disturbances and noise coming from the hybrid buck circuit 2340 to the oscillator circuit 2310.

[0189] According to some embodiments, there may be circuitry and / or devices configured to control the power inductor 2342 and the one or more isolating capacitors 2380 based on the output of the counter circuit 2390 such that the one or more isolating capacitors 2380 are charged at an integer multiple and / or an integer division of the frequency of the signals of the oscillator circuit 2310, for example integer multiples and / or integer divisions in similar ranges to those already described herein. For example, there may be one or more control switches 2370 configured to activate and deactivate current flow into, out of, and / or between the one or more isolating capacitors 2380.

[0190] While a particular arrangement of components is shown in FIG. 23B, embodiments of the present invention may include any arrangement of circuits and / or components that allow the power inductor 2342 to be isolated from the oscillator circuit 2310 but still provide power to the oscillator circuit 2310 such that oscillations of the oscillator circuit 2310 do not fade. In some embodiments, the one or more isolating capacitors 2380 and the one or more control switches 2370 may accomplish this.

[0191] Returning to FIG. 23A, according to some embodiments, the diode 2346 may be silicon or gallium arsenide to reduce the forward-drive voltage for the charge drawn from ground. Oscillations of the oscillator circuit 2310 may have a frequency that both fits within the RIP measurement frequencies discussed above and is appropriate for the operation of the hybrid buck circuit 2340.

[0192] According to some embodiments, the size of the power inductor 2342 may be selected such that it provides the correct amount of charge to maintain the oscillations within the oscillator circuit 2310 at a set amplitude, for example an amplitude in the range of 0.01 V to 2.5V, preferably in the range from 0.1V to 2V, more preferably in the range from 0.5V to 1.5V, more preferably in the range from 0.55V to IV, and more preferably in the range from 0.6V to 0.9V. According to some particularly advantageous embodiments, the oscillations may oscillate at an amplitude of 400mV.

[0193] FIG. 23A also shows that a coupling capacitor 2360 may connect the oscillator circuit 2310 to the comparator circuit 2320. The coupling capacitor 2360 may provide a DC-shift to the oscillations in the oscillator circuit 2310 so that the comparator circuit 2320 may have an input within the range of 0V-3V.

[0194] To illustrate some advantages of embodiments of the RIP device 2300, FIG. 24A illustrates a simulation of a RIP device according to some embodiments described herein, and FIG. 24B illustrates a simulation of a RIP device according to some embodiments described herein. More particularly, FIG. 24A illustrates the current flow 2410 through the power inductor 2342 according to some embodiments and the oscillations 2420 within the oscillator circuit 2310 according to some embodiments. As shown in FIG. 24A, the current for approximately the first quarter of the oscillations 2420 in the oscillator circuit 2310 may be provided by the power inductor 2342 according to some embodiments. As described above, the majority of this current may be drawn from ground over the diode 2346 instead of from the power supply 2350, which may enable a longer lasting power supply and an increased power efficiency of the RIP device 2300.

[0195] FIG. 24B shows a power inductor current flow 2415, an oscillator signal 2425, a power supply current flow 2435, and a ground current flow 2445. As shown in FIG. 24B, around 25% of the current may originate from the battery while around 75% of the current may come over the diode 2346 according to some embodiments. This may beneficially reduce total energy consumption from the power supply 2350 and improve the life of the power supply 2350.

[0196] Returning to FIG. 23A, according to some embodiments the RIP device 2300 may reduce and / or completely eliminate the risk of interference between the hybrid buck circuit 2340 and the oscillator circuit 2310 by synchronizing them. The RIP device 2300 may also beneficially allow low voltage components such as the oscillator circuit to be run form a higher voltage source, for example a 3 V voltage source, in a single step over the power inductor 2342.

[0197] According to some embodiments, a series inductor (not shown) may be included in series with the inductor 2312 of the oscillator circuit 2310 according to similar embodiments described above.

[0198] Referring now to FIGS. 25A-25E, FIG. 25A illustrates a top plan view of an embodiment of a RIP device described herein. FIG. 25B illustrates a perspective view of the RIP device according to FIG. 25A. FIG. 25C illustrates a perspective view of a RIP device that shows an interior of the RIP device according to FIG. 25A. FIG. 25D illustrates a sideview of the RIP device according to FIG. 25A. FIG. 25E illustrates a side view of the RIP device according to FIG. 25A.

[0199] FIGS. 25A-25E illustrate that a RIP device 2500 may include a housing 2510 that may be configured to house the RIP device discussed above in relation to FIGS. 9A-24B. For example, as shown in FIG. 25C, the housing 2510 may include a cutout area 2515 in which an electronic device 2520 may be disposed. The electronic device may be similar to embodiments discussed above in relation to FIGS. 9A-24B. As discussed above, the RIP device may operate at a low power, and accordingly a small battery 2530 may be housed within the housing 2510. This may enable a more compact housing as discussed below in relation to FIGS. 26 A and 26B.

[0200] According to some embodiments, the RIP device 2500 may have a low weight. For example, because the battery and RIP device discussed above in relation to FIGS. 9A-24B may operate at a low power using compact components, the RIP device 2500 may weigh in the range from 3g to 69g, preferably in the range from 5g to 60g, more preferably in the range from 7g to 50g, more preferably in the range from 8g to 40g, more preferably in the range from 9g to 30g, more preferably in the range from 10g to 20g, and even more preferably in the range from 11g to 15g. In some particularly advantageous embodiments, the RIP device 2500 may weigh 12.5g.

[0201] Examples of known RIP devices may weigh greater than 69.5g excluding the batteries. Including batteries, known examples of RIP devices may have a weight of 92g. As discussed above, embodiments of the present disclosure provide a significantly lighter RIP device than known RIP devices, which beneficially allow the RIP devices according to the present disclosure to be more comfortable and convenient to a patient. This beneficially enables an improved patient experience by measuring the patient’s sleep without disturbing the sleep. This in turn improves the quality of the data gathered because the data more closely reflect the normal sleep of the patient.

[0202] FIGS. 25A-25E also illustrate that the housing 2510 may have a rectangular shape. This disclosure is not limited to a housing 2510 with a rectangular shape, and instead embodiments of the present disclosure may include a housing with any shape, including triangular, quadrilateral, trapezoidal, pentagonal, polygonal, circular, and / or ovular, and also including any three dimensional variants thereof, including spherical, conical, cylindrical, ellipsoidal, polyhedron, and / or prismatic.

[0203] Referring now to FIG. 26A, FIG. 26A illustrates a perspective view of an embodiment of a RIP device according to some embodiments described herein. FIG. 26A shows that a RIPdevice 2600 may be connected to another embodiment of a RIP device 2650. For example, the RIP device 2600 may be attached to a RIP belt that is connected around a patient’s thorax, and the RIP device 2650 may be attached to a RIP belt that is connected around a patient’s abdomen. According to some embodiments, there may be a connecting wire 2640 between the RIP device 2600 and the RIP device 2650 that may provide physical support and an electrical connection between the RIP device 2600 and the RIP device 2650.

[0204] According to some embodiments, there may be more than one, more than two, or more than three RIP devices connected to each other with a connecting wire 2640. According to some embodiments, the more than one RIP devices may communicate with one another through the connecting wire 2640. For example, the RIP device 2600 may communicate with the RIP device 2650. As an illustrative example, the RIP device 2600 may be configured to transmit data to a server. The RIP device 2650 may be configured to transmit data to the RIP device 2600.

[0205] According to some embodiments, the RIP devices may communicate with one another over a wireless connection, for example a Bluetooth connection. The RIP devices may communicate with one another over a wireless connection based on a wireless network.

[0206] In some advantageous embodiments, the RIP device 2650 may be configured only to receive oscillating signals from an oscillator circuit, for example a RIP belt. The RIP device 2650 may then transmit the oscillating signals to the RIP device 2600. According to some embodiments, the RIP device 2650 may not include a battery and instead runs on a battery in the RIP device 2600 to which the RIP device 2650 is connected. This may beneficially reduce the size and weight of the RIP device 2650 such that the RIP device 2650 may be smaller and lighter than the RIP device 2600. In some embodiments, the battery of the RIP device 2600 may provide power to the RIP device 2650 through the connecting wire 2640. According to some embodiments, the RIP device 2650 may have its own battery by which the RIP device 2650 may be powered.

[0207] According to some particularly advantageous the RIP device 2600, the connecting wire 2640, and the RIP device 2650 may have a combined weight in the range from 4g to 69g, preferably in the range from 8g to 60g, more preferably in the range from 12g to 50g, more preferably in the range from 15g to 40g, more preferably in the range from 16g to 30g, more preferably in the range from 17g to 20g, and even more preferably in the range from 18g to 19.5g. In some particularly advantageous embodiments, the RIP device 2600, the connecting wire 2640, and the RIP device 2650 may have a combined weight of 19g.

[0208] As discussed above, known examples of RIP devices weigh greater than 69.5g excluding the batteries. Including batteries, known examples of RIP devices have a weight of 92g. As discussed above, embodiments of the present disclosure provide a significantly lighter RIP device than known RIP devices, which beneficially allows the RIP devices according to the present disclosure to be more comfortable and convenient to a patient. This beneficially enables an improved patient experience by measuring the patient’s sleep without disturbing the sleep. This in turn improves the quality of the data gathered because the data more closely reflects the normal sleep of the patient.

[0209] Referring now to FIG. 26B, FIG. 26B illustrates an enlarged view of the RIP device 2600 of FIG. 26A. FIG. 26B illustrates that the RIP device 2600 may include a housing 2605 that may have a shape that is defined in an x-dimension 2610, a y-dimension 2620, and a z- dimension 2630. According to some embodiments, the housing 2605 may be configured to house a RIP device similar to embodiments of a RIP device discussed above in relation to FIGS. 9A-24B.

[0210] According to some embodiments, the RIP device 2600 may include one or more electrically conductive terminals. For example, on an exterior portion 2606 of the housing 2605, there may be one or more snap connectors 2608 that may be configured to provide a snap connection to a RIP belt. The one or more snap connectors 2608 may thus be the electrically conductive terminals according to some embodiments and may provide electrical connection between the RIP belt and the RIP device housed within the housing 2605.

[0211] A significant advantage of some embodiments of the present disclosure may include that the size of the shape in the x-dimension 2610, y-dimension 2620, z-dimension 2630 may be small. For example, the RIP device 2600 may have an x-dimension 2610 in the range from 35mm to 100mm, preferably in the range from 45mm to 90mm, more preferably in the range from 55mm to 80 mm, more preferably in the range from 65mm to 75mm, and more preferably in the range from 69mm to 71mm. According to a particularly advantageous embodiment, the RIP device 2600 may have an x-dimension 2610 that is 70.16mm.

[0212] FIG. 26B also shows that the RIP device 2600 may have a y-dimension 2620 in the range from 15mm to 45mm, preferably in the range from 20mm to 40mm, more preferably in the range from 25mm to 35mm, and more preferably in the range from 30mm to 31mm. according to a particularly advantageous embodiment, the RIP device 2600 may have a y- dimension 2620 that is 30.86mm.

[0213] FIG. 26B additionally shows that the RIP device 2600 may have a z-dimension 2630 in the range from 5mm to 15mm, preferably in the range from 7mm to 13mm, morepreferably in the range from 10mm to 12mm. According to a particularly advantageous embodiment, the RIP device 2600 may have a z-dimension 2630 that is 11.02mm.

[0214] As discussed above, embodiments of the present disclosure may provide a significantly more compact RIP device than known RIP devices, which may beneficially allow the RIP devices according to the present disclosure to be more comfortable and convenient to a patient. This may beneficially enable an improved patient experience by measuring the patient’s sleep without disturbing the sleep. This may in turn improve the quality of the data gathered because the data may more closely reflect the normal sleep of the patient.

[0215] Referring now to FIG. 27, FIG. 27 illustrates a buck and boost RIP device according to some embodiments described herein. FIG. 27 shows that a buck and boost RIP device 2700 may contain an oscillator circuit 2710 that includes an inductor 2712 connected in parallel with a first capacitor 2714 and in series with a second capacitor 2716. According to some embodiments, the inductor 2712, the first capacitor 2714, and the second capacitor 2716 may all have some series resistance that may cause oscillations within the oscillator circuit 2710 to fade out over time.

[0216] FIG. 27 also shows that the buck and boost RIP device 2700 may include a power source 2720. The oscillator circuit 2710 may require energy from the power source 2720 in order to maintain oscillations within the oscillator circuit 2710. Because the oscillator circuit 2710 may operate at a much lower voltage than the voltage of the power source 2720, the RIP device 2700 may include a first energy preserving inductor 2730 a first switch 2740, and a first diode 2750.

[0217] FIG. 27 illustrates that the first switch 2740 may be configured such that the first switch 2740 may expose the first energy preserving inductor 2730 to the power source 2720 when the first switch 2740 is activated, and may break the connection between the first energy preserving inductor 2730 and the power source 2720 when it is deactivated. According to some embodiments, the first switch 2740 may be configured to activate only long enough for the first energy preserving inductor 2730 to be fully charged, at which point the first switch 2740 may be deactivated.

[0218] According to some embodiments, by deactivating the first switch 2740 when the first energy preserving inductor 2730 has been fully charged, an induced current may continue drawing charge from the second capacitor 2716 over the first diode 2750. Because a voltage difference between the first capacitor 2714 and the second capacitor 2716 may be within an amplitude of the oscillation of an oscillation signal within the oscillator circuit 2710 , amajority of the energy lost by the first capacitor 2714 may come from the second capacitor 2716 to the first capacitor 2714 via the first energy preserving inductor 2730 and first diode 2750. Such may beneficially reduce the amount of energy wasted by the buck and boost RIP device 2700.

[0219] According to some embodiments, a resistor load (not shown) may be placed over the second capacitor 2716 to drain the remaining energy. FIG. 27 additionally shows that the buck and boost RIP device 2700 may include a second energy preserving inductor 2735, a second switch 2745, and a second diode 2755. According to some embodiments, the second energy preserving inductor 2735 may be connected to the second capacitor 2716 on one end and over the second switch 2745 to ground on the other side. The second switch 2745 may be closed during the beginning of the discharge of the second capacitor 2716. This may beneficially allow the second energy preserving inductor 2735 to induce a current that keeps flowing over the second diode 2755 and into the first capacitor 2714.

[0220] According to some embodiments, by conserving both the source and drain energy of the oscillator circuit 2710, the DC operating point of oscillations within the oscillator circuit 2710 may be selected to be anywhere within the voltage range of the power source 2720, for example one half of the voltage of the power source 2720. This may beneficially enable the first energy preserving inductor 2730 and the second energy preserving inductor 2735 to equally contribute to the charging of the first capacitor 2714. For example, the power source 2720 may be a voltage of 3V and the DC operating point may be selected to be 1.5V.

[0221] According to some embodiments, the first switch 2740 and the second switch 2745 may be transistors, for example enhancement p-channel MOSFETs. The first diode 2750 and the second diode 2755 may be traditional diodes, but may as well be bipolar transistors connected as super-diodes. According to some embodiments, the first diode 2750 and the second diode 2755 may be more sophisticated rectifying switches in order to minimize the voltage drop and thus the power loss of the diodes. In at least such a way, the buck and boost RIP device 2700 may operate in at low power.

[0222] Referring now to FIG. 28, FIG. 28 illustrates a RIP device according to some embodiments described herein. As shown in FIG. 28, a RIP device 2800 may include one or more comparators 2810, one or more band stop filters 2820, one or more pulse shaping filters 2830, one or more pull up resistors 2840 and one or more inputs 2850 configured to receive an oscillating signal. According to some embodiments, each of the above may be included in a thorax RIP device 2801 and / or an abdomen RIP device 2802.

[0223] FIG. 28 additionally shows that the one or more pulse shaping filters 2830 may be connected to the outputs of the one or more comparators 2810 such that they convert the output of the comparators into an impulse like signal. The one or more band stop filters 2820 may allow DC voltage to pass through to regulate the input voltage to operate around a reference voltage, which may be around one half of a supply voltage as discussed above. The one or more band stop filters 2820 may also attenuate all frequencies between 0.5kHz and 100kHz which may beneficially reduce noise in the signal.

[0224] FIG. 28 also shows that the one or more pull up resistors 2840 may put the inputs of the one or more comparators into a definite state when no oscillating signal is present at the one or more inputs 2850. This may beneficially stop all oscillations within the RIP device 2800, which may conserve power.

[0225] According to some embodiments, the one or more band stop filters 2820 may have greater than 330KOHm pass-through resistance, which may keep DC current in the RIP device 2800 under I Op A.

[0226] Certain embodiments of the present disclosure may include an energy preserving power source. Such an energy preserving power source may include the low voltage DC source 1430 and / or the low voltage DC source 950 discussed above with reference to FIGS.9 A, 9B, 10, and 14, including the discussed DC-DC converter above. Other energy preserving power sources are enabled by the present disclosure, and embodiments of the present disclosure may include one or more different power preserving power sources.

[0227] For example, embodiments similar to the hybrid buck circuit 2340 of FIG. 23A and embodiments discussed in relation to the buck and boost RIP device 2700 of FIG. 27 above may also be considered energy preserving power sources. According to some embodiments, an energy preserving power source may be any device or circuit configured to reduce the overall energy consumption of a RIP device.

[0228] As another illustrative example, if a battery is used that provides a voltage, for example three volts, the energy preserving power source may provide a voltage in the range from 0.1V to 2.9V, preferably in the range from 0.2V to 2.5V, more preferably in the range from 0.3V to 2V, more preferably in the range from 0.4V to 1.5V, more preferably in the range from 0.5V to 0.1V. According to some particularly advantageous embodiments, the energy preserving power source may provide a voltage of 0.6V.

[0229] According to some embodiments, the energy preserving power source may be, for example, a step-down regulator and / or a step-down converter and may operate at an integer multiple of the frequency of an oscillator circuit, for example a RIP sensor, in the range from1 to 10, preferably in the range from 2 to 9, more preferably in the range from 3 to 8, more preferably in the range from 4 to 7, and / or more preferably in the range from 5 to 6. Additionally or alternatively, the energy preserving power source may operate at an integer division of the frequency of an oscillator circuit, for example a RIP sensor, for example an integer division in the range from 1 / 32 to 1 / 2, preferably in the range from 1 / 16 to 1 / 3, more preferably in the range from 1 / 10 to 1 / 4, more preferably in the range from 1 / 8 to 1 / 5, and / or preferably in the range from 1 / 7 to 1 / 6. According to some particularly advantageous embodiments, the energy preserving power source may operate at an integer division of 1 / 16 of the frequency of the oscillator circuit.

[0230] Certain terms are used throughout the description and claims to refer to particular methods, features, or components. This disclosure does not intend to distinguish between methods, features, or components that differ in name but not function. The figures are not necessarily drawn to scale. Certain features and components herein may be shown in exaggerated scale or in somewhat schematic form and some details of conventional elements may not be shown or described in interest of clarity and conciseness.

[0231] Certain embodiments described herein can be stored on computer storage media and performed using a computation / logic circuitry. For example, certain embodiments may be performed on a central processing unit (CPU). Computer storage media are physical storage media that store computer-executable instructions and / or data structures. Physical storage media include computer hardware, such as RAM, ROM, EEPROM, solid state drives (“SSDs”), flash memory, phase-change memory (“PCM”), optical disk storage, magnetic disk storage or other magnetic storage devices, or any other hardware storage device(s) which can be used to store program code in the form of computer-executable instructions or data structures, which can be accessed and executed by a general-purpose or special-purpose computer system to implement the disclosed functionality of the disclosure.

[0232] Transmission media can include a network and / or data links which can be used to carry program code in the form of computer-executable instructions or data structures, and which can be accessed by a general-purpose or special-purpose computer system. A “network” may be defined as one or more data links that enable the transport of electronic data between computer systems and / or modules and / or other electronic devices. When information is transferred or provided over a network or another communications connection (either hardwired, wireless, or a combination of hardwired or wireless) to a computer system, the computer system may view the connection as transmission media. Combinations of the above should also be included within the scope of computer-readable media.

[0233] Further, upon reaching various computer system components, program code in the form of computer-executable instructions or data structures can be transferred automatically from transmission media to computer storage media (or vice versa). For example, computerexecutable instructions or data structures received over a network or data link can be buffered in RAM within a network interface module (e.g., a “NIC”), and then eventually transferred to computer system RAM and / or to less volatile computer storage media at a computer system. Thus, it should be understood that computer storage media can be included in computer system components that also (or even primarily) utilize transmission media.

[0234] Computer-executable instructions may comprise, for example, instructions and data which, when executed by one or more processors, cause a general-purpose computer system, special-purpose computer system, or special-purpose processing device to perform a certain function or group of functions. Computer-executable instructions may be, for example, binaries, intermediate format instructions such as assembly language, or even source code.

[0235] The disclosure of the present application may be practiced in network computing environments with many types of computer system configurations, including, but not limited to, personal computers, desktop computers, laptop computers, message processors, hand-held devices, multi-processor systems, microprocessor-based or programmable consumer electronics, network PCs, minicomputers, mainframe computers, mobile telephones, PDAs, tablets, pagers, routers, switches, and the like. The disclosure may also be practiced in distributed system environments where local and remote computer systems, which are linked (either by hardwired data links, wireless data links, or by a combination of hardwired and wireless data links) through a network, both perform tasks. As such, in a distributed system environment, a computer system may include a plurality of constituent computer systems. In a distributed system environment, program modules may be located in both local and remote memory storage devices.

[0236] The disclosure of the present application may also be practiced in a cloud-computing environment. Cloud computing environments may be distributed, although this is not required. When distributed, cloud computing environments may be distributed internationally within an organization and / or have components possessed across multiple organizations. In this description and the following claims, “cloud computing” is defined as a model for enabling on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services). The definition of “cloud computing” is not limited to any of the other numerous advantages that can be obtained from such a model when properly deployed.

[0237] A cloud-computing model can be composed of various characteristics, such as on- demand self-service, broad network access, resource pooling, rapid elasticity, measured service, and so forth. A cloud-computing model may also come in the form of various service models such as, for example, Software as a Service (“SaaS”), Platform as a Service (“PaaS”), and Infrastructure as a Service (“laaS”). The cloud-computing model may also be deployed using different deployment models such as private cloud, community cloud, public cloud, hybrid cloud, and so forth.

[0238] Some embodiments, such as a cloud-computing environment, may comprise a system that includes one or more hosts that are each capable of running one or more virtual machines. During operation, virtual machines emulate an operational computing system, supporting an operating system and perhaps one or more other applications as well. In some embodiments, each host includes a hypervisor that emulates virtual resources for the virtual machines using physical resources that are abstracted from view of the virtual machines. The hypervisor also provides proper isolation between the virtual machines. Thus, from the perspective of any given virtual machine, the hypervisor provides the illusion that the virtual machine is interfacing with a physical resource, even though the virtual machine only interfaces with the appearance (e.g., a virtual resource) of a physical resource. Examples of physical resources including processing capacity, memory, disk space, network bandwidth, media drives, and so forth.

[0239] Some embodiments of the present disclosure can be stored on computer storage media and performed using a computation / logic circuitry. Computer storage media are physical storage media that store computer-executable instructions and / or data structures. Physical storage media include computer hardware, such as RAM, ROM, EEPROM, solid state drives (“SSDs”), flash memory, phase-change memory (“PCM”), optical disk storage, magnetic disk storage or other magnetic storage devices, or any other hardware storage device(s) which can be used to store program code in the form of computer-executable instructions or data structures, which can be accessed and executed by a general-purpose or special-purpose computer system to implement the disclosed functionality of the disclosure.

[0240] Transmission media can include a network and / or data links which can be used to carry program code in the form of computer-executable instructions or data structures, and which can be accessed by a general-purpose or special-purpose computer system. A “network” may be defined as one or more data links that enable the transport of electronic data between computer systems and / or modules and / or other electronic devices. When information is transferred or provided over a network or another communications connection(either hardwired, wireless, or a combination of hardwired or wireless) to a computer system, the computer system may view the connection as transmission media. Combinations of the above should also be included within the scope of computer-readable media.

[0241] Further, upon reaching various computer system components, program code in the form of computer-executable instructions or data structures can be transferred automatically from transmission media to computer storage media (or vice versa). For example, computerexecutable instructions or data structures received over a network or data link can be buffered in RAM within a network interface module (e.g., a “NIC”), and then eventually transferred to computer system RAM and / or to less volatile computer storage media at a computer system. Thus, it should be understood that computer storage media can be included in computer system components that also (or even primarily) utilize transmission media.

[0242] Computer-executable instructions may comprise, for example, instructions and data which, when executed by one or more processors, cause a general-purpose computer system, special-purpose computer system, or special-purpose processing device to perform a certain function or group of functions. Computer-executable instructions may be, for example, binaries, intermediate format instructions such as assembly language, or even source code.

[0243] The disclosure of the present application may be practiced in network computing environments with many types of computer system configurations, including, but not limited to, personal computers, desktop computers, laptop computers, message processors, hand-held devices, multi-processor systems, microprocessor-based or programmable consumer electronics, network PCs, minicomputers, mainframe computers, mobile telephones, PDAs, tablets, pagers, routers, switches, and the like. The disclosure may also be practiced in distributed system environments where local and remote computer systems, which are linked (either by hardwired data links, wireless data links, or by a combination of hardwired and wireless data links) through a network, both perform tasks. As such, in a distributed system environment, a computer system may include a plurality of constituent computer systems. In a distributed system environment, program modules may be located in both local and remote memory storage devices.

[0244] The disclosure of the present application may also be practiced in a cloud-computing environment. Cloud computing environments may be distributed, although this is not required. When distributed, cloud computing environments may be distributed internationally within an organization and / or have components possessed across multiple organizations. In this description and the following claims, “cloud computing” is defined as a model for enabling on-demand network access to a shared pool of configurable computing resources(e.g., networks, servers, storage, applications, and services). The definition of “cloud computing” is not limited to any of the other numerous advantages that can be obtained from such a model when properly deployed.

[0245] A cloud-computing model can be composed of various characteristics, such as on- demand self-service, broad network access, resource pooling, rapid elasticity, measured service, and so forth. A cloud-computing model may also come in the form of various service models such as, for example, Software as a Service (“SaaS”), Platform as a Service (“PaaS”), and Infrastructure as a Service (“laaS”). The cloud-computing model may also be deployed using different deployment models such as private cloud, community cloud, public cloud, hybrid cloud, and so forth.

[0246] Some embodiments, such as a cloud-computing environment, may comprise a system that includes one or more hosts that are each capable of running one or more virtual machines. During operation, virtual machines emulate an operational computing system, supporting an operating system and perhaps one or more other applications as well. In some embodiments, each host includes a hypervisor that emulates virtual resources for the virtual machines using physical resources that are abstracted from view of the virtual machines. The hypervisor also provides proper isolation between the virtual machines. Thus, from the perspective of any given virtual machine, the hypervisor provides the illusion that the virtual machine is interfacing with a physical resource, even though the virtual machine only interfaces with the appearance (e.g., a virtual resource) of a physical resource. Examples of physical resources including processing capacity, memory, disk space, network bandwidth, media drives, and so forth.

[0247] Although various example embodiments have been described in detail herein, many modifications are possible in the example embodiments without materially departing from the concepts of present disclosure. Accordingly, any such modifications are intended to be included in the scope of this disclosure. Likewise, while the disclosure herein contains many specifics, these specifics should not be construed as limiting the scope of the disclosure or of any of the appended claims, but merely as providing information pertinent to one or more specific embodiments that may fall within the scope of the disclosure and the appended claims. Any described features from the various embodiments disclosed may be employed in combination. In addition, other embodiments of the present disclosure may also be devised which lie within the scopes of the disclosure and the appended claims. Each addition, deletion, and modification to the embodiments that falls within the meaning and scope of the claims is to be embraced by the claims.

[0248] Certain embodiments and features may have been described using a set of numerical upper limits and a set of numerical lower limits. Ranges including the combination of any two values, e.g., the combination of any lower value with any upper value, the combination of any two lower values, and / or the combination of any two upper values are contemplated unless otherwise indicated. Certain lower limits, upper limits and ranges may appear in one or more claims below. Any numerical value is “about” or “approximately” the indicated value, and takes into account experimental error and variations that would be expected by a person having ordinary skill in the art.

[0249] This disclosure provides various examples, embodiments, and features which, unless expressly stated or which would be mutually exclusive, should be understood to be combinable with other examples, embodiments, or features described herein.

[0250] In addition to the above, further embodiments and examples include the following:

[0251] GROUP 1: Low Power RIP Respiratory Inductive Plethysmograph (RIP) Devices

[0252] Methods, Devices, and Systems for low power Respiratory Inductive Plethysmograph (RIP) devices.

[0253] 1-1: A Respiratory Inductive Plethysmograph (RIP) device, wherein the RIP device is configured to receive one or more RIP signals and to transmit the one or more RIP signals over a wireless and / or wired connection, wherein the RIP device is configured to operate at low power.

[0254] 1-2: The RIP device according to any one or a combination of one or more of 1-1 above and / or 1-3 to 1-12 below, wherein the RIP device is configured to operate on low power by reducing the size of the one or more RIP signals that the RIP device transmits over the wireless and / or wired connection.

[0255] 1-3: The RIP device according to any one or a combination of one or more of 1-1 to 1-2 above and / or 1-4 to 1-12 below, wherein the RIP device is configured to compress the one or more RIP signals into a compressed output signal, and is further configured to transmit the compressed output signal over the wireless and / or wired connection.

[0256] 1-4: The RIP device according to any one or a combination of one or more of 1-1 to 1-3 above and / or 1-5 to 1-12 below, wherein the RIP device is configured to sample the one or more RIP signals in order to produce a first sample and a second sample, wherein the first sample occurs before the second sample.

[0257] 1-5: The RIP device according to any one or a combination of one or more of 1-1 to 1-4 above and / or 1-6 to 1-12 below, wherein the RIP device is configured to sample the one ormore RIP signals in order to produce a first sample and a second sample, wherein the RIP device is further configured to compare the first and second samples, wherein the RIP device is further configured to reduce the size of the second sample based on the comparison between the first and second samples.

[0258] 1-6: The RIP device according to any one or a combination of one or more of 1-1 to 1-5 above and / or 1-7 to 1-12 below, wherein the RIP device is configured to operate at a voltage of 0.6V, 0.5V, 0.4V, 0.3V, 0.2V, and / or 0.1V.

[0259] 1-7: The RIP device according to any one or a combination of one or more of 1-1 to 1-6 above and / or 1-8 to 1-12 below, wherein the RIP device is configured to operate at a voltage in the range of 0.01V to 3V.

[0260] 1-8: The RIP device according to any one or a combination of one or more of 1-1 to 1-7 above and / or 1-12 below, wherein the RIP device is configured to send the one or more RIP signals over a wireless connection to a server.

[0261] 1-9: The RIP device according to any one or a combination of one or more of 1-1 to 1-8 above and / or 1-10 to 1-12 below, wherein the RIP device is configured to send the one or more RIP signals over a Bluetooth connection to a server.

[0262] 1-10: The RIP device according to any one or a combination of one or more of 1-1 to 1-9 above and / or 1-11 to 1-12 below, wherein the RIP device is configured to communicate with another RIP device over a wireless connection.

[0263] 1-11: The RIP device according to any one or a combination of one or more of 1-1 to 1-10 above and / or 1-12 below, wherein the RIP device is configured to communicate with another RIP device over a wired connection.

[0264] 1-12: The RIP device according to any one or a combination of one or more of 1-1 to 1-11 above, wherein the RIP device is configured to communicate with another RIP device over a Bluetooth connection.

[0265] 1-13: A method for capturing and low power transmission of Respiratory Inductive Plethysmograph (RIP) signals comprising: receiving one or more RIP signals; sampling the one or more RIP signals to produce a first sample and a second sample, wherein the second sample occurs after the first sample; comparing the second sample to the first sample; after comparing the second sample to the first sample, reducing the size of the second sample by encoding the second sample as a delta from the first sample; and transmitting the first sample and / or the second sample.

[0266] 1-14: The method according to any one or a combination of one or more of 1-13 above and / or 1-15 to 1-17 below, wherein, before reducing the size of the second sample, the first sample and second sample have the same size.

[0267] 1-15: The method according to any one or a combination of 1-13 to 1-14 above and / or 1-16 to 1-17 below, wherein the first sample has a size that is 32 bits and the second sample has a size that, after reducing the size of the second sample, is 8 bits.

[0268] 1-16: The method according to any one or a combination of 1-13 to 1-15 above and / or1-17 to 1-17 below, wherein reducing the size of the second sample only occurs if the comparison between the second sample and the first sample yields a small enough delta for the second sample to be encoded as a delta from the first sample.

[0269] 1-17: The method according to any one or a combination of 1-13 to 1-16 above, wherein the delta is in the range from -64 to 63.

[0270] 1-18: A method for low power operation of a RIP device comprising: producing a power source that provides a first voltage; lowering the first voltage to a second voltage; producing a RIP device; and connecting the RIP device to the power source such that the RIP device operates on at the second voltage.

[0271] 1-19: A hardware storage device having stored thereon computer executable instructions which, when executed by one or more processors of a computer system, configure the computer system to perform the method according to any one or a combination of one or more of methods 1-13 to 1-18 above.

[0272] Group 2 - Low Power Respiratory Inductive Plethysmograph (RIP) Systems

[0273] Methods, Devices, and Systems for low power Respiratory Inductive Plethysmograph (RIP) systems.

[0274] 2-1: A low power Respiratory Inductive Plethysmograph (RIP) system comprising the low power RIP device according to any one or a combination of one or more of 1-1 to 1-12 above and a RIP belt, wherein the RIP belt is configured to generate RIP signals and to input the RIP signals into the RIP device.

[0275] 2-2: The RIP system according to any one or a combination of one or more of 2-1 above and / or 2-3 to 2-8 below, wherein the RIP system further comprises a server, wherein the server is configured to receive the one or more signals transmitted by the RIP device.

[0276] 2-3: The RIP system according to any one or a combination of one or more of 2-1 to2-2 above and / or 2-4 to 2-8 below, wherein the RIP system further comprises one or more additional RIP devices.

[0277] 2-4: The RIP system according to any one or a combination of one or more of 2-1 to 2-3 above and / or 2-5 to 2-8 below, wherein each of the low power RIP devices is configured to communicate with one another.

[0278] 2-5: The RIP system according to any one or a combination of one or more of 2-1 to 2-4 above and / or 2-6 to 2-8 below, wherein each of the RIP devices is configured to communicate with one another over a wireless connection and / or a wired network and / or connection.

[0279] 2-6: The RIP system according to any one or a combination of one or more of 2-1 to 2-5 above and / or 2-7 to 2-8 below, wherein each of the RIP devices is configured to communicate with a server over a wireless and / or a wired network and / or connection.

[0280] 2-7: The RIP system according to any one or a combination of one or more of 2-1 to 2-6 above and / or 2-8 below, wherein each of the RIP devices is configured to transmit RIP data and / or RIP signals over a wireless and / or wired network and / or connection.

[0281] 2-8: The RIP system according to any one or a combination of one or more of 2-1 to 2-7 above, wherein the server is configured to analyze the data that each RIP device transmits to the server.

[0282] 2-9: A method for capturing and low power transmission Respiratory Inductive Plethysmograph (RIP) signals comprising: producing one or more RIP devices, producing one or more RIP belt, and connecting exactly one RIP belt to each respective RIP belt.

[0283] 2-10: The method according to any one or a combination of 2-9 above and / or 2-11 below, wherein the method further comprises providing a server and connecting the one or more RIP devices to the server over a wireless and / or wired connection.

[0284] 2-11: The method according to any one or a combination of 2-9 to 2-10 above, wherein there are two or more RIP devices, and wherein each of the one or more RIP devices is connected to at least one other RIP device over a wired and / or wireless connection.

[0285] Group 3 - Respiratory Inductive Plethysmograph (RIP) devices and Methods

[0286] Methods, Devices, and Systems for low power Respiratory Inductive Plethysmograph (RIP) devices.

[0287] 3-1: A Respiratory Inductive Plethysmograph (RIP) device comprising: an oscillator circuit configured to generate an oscillator signal; an amplifier circuit connected to the oscillator circuit, wherein the amplifier circuit is configured to receive as an input an AC component of the oscillator signal and to output an amplifier output signal based on the AC component of the oscillator signal and a voltage controlled switch connected to the oscillatorcircuit and to the amplifier circuit, wherein the voltage controlled switch is configured to receive the amplifier output signal as an input and to output current to the oscillator circuit.

[0288] 3-2: The RIP device of any one or a combination of one or more of 3-1 above and / or 3-3 to 3-18 below, wherein the RIP device further comprises a comparator connected to the amplifier circuit, wherein the comparator is configured to receive the amplifier output signal.

[0289] 3-3: The RIP device of any one or a combination of one or more of 3-1 to 3-2 above and / or 3-4 to 3-18 below, wherein the RIP device further comprises an offset voltage controller configured to provide a DC bias to the amplifier output signal at the voltage controlled switch.

[0290] 3-4: The RIP device of any one or a combination of one or more of 3-1 to 3-3 above and / or 3-5 to 3-18 below, wherein the oscillator circuit comprises an inductor and a capacitor connected in parallel, wherein the oscillator circuit further comprises a series inductor connected in series with the inductor and in parallel with the capacitor.

[0291] 3-5: The RIP device of any one or a combination of one or more of 3-1 to 3-4 above and / or 3-6 to 3-18 below, wherein the oscillator circuit further comprises a series inductor connected in series with the inductor and in parallel with the capacitor.

[0292] 3-6: The RIP device of any one or a combination of one or more of 3-1 to 3-5 above and / or 3-7 to 3-18 below, wherein the series inductor has an inductance of 2.2pH and the inductor has an inductance in the range from 0.5pH to 7pH.

[0293] 3-7: The RIP device of any one or a combination of one or more of 3-1 to 3-6 above and / or 3-8 to 3-18 below, wherein the series inductor has a variable inductance.

[0294] 3-8: The RIP device of any one or a combination of one or more of 3-1 to 3-7 above and / or 3-9 to 3-18 below, wherein the inductor of the oscillator circuit comprises a RIP belt.

[0295] 3-9: The RIP device of any one or a combination of one or more of 3-1 to 3-8 above and / or 3-10 to 3-18 below, wherein the oscillator circuit further comprises a transformer through which the oscillator is connected to the amplifier circuit and voltage controlled switch.

[0296] 3-10: The RIP device of any one or a combination of one or more of 3-1 to 3-9 above and / or 3-11 to 3-18 below, wherein the amplifier circuit amplifies signals that have frequencies in the range from 200kHz to 500kHz.

[0297] 3-11: The RIP device of any one or a combination of one or more of 3-1 to 3-10 above and / or 3-12 to 3-18 below, wherein the amplifier circuit has a phase shift of 360 degrees for signals that have frequencies in the range from 200kHz to 500kHz.

[0298] 3-12: The RIP device of any one or a combination of one or more of 3-1 to 3-11 above and / or 3-13 to 3-18 below, wherein the amplifier circuit dampens all DC signals from its input to its output.

[0299] 3-13: The RIP device of any one or a combination of one or more of 3-1 to 3-12 above and / or 3-14 to 3-18 below, wherein the offset voltage controller is configured to provide a selectable bias voltage of 0.79V, 0.64V, 0.45V, and / or 0.37V and / or in the range from 0.1V to 1.5 V.

[0300] 3-14: The RIP device of any one or a combination of one or more of 3-1 to 3-13 above and / or 3-15 to 3-18 below, wherein the RIP device further comprises a kick circuit configured to start oscillations within the oscillator circuit.

[0301] 3-15: The RIP device of any one or a combination of one or more 3-1 to 3-14 above and / or 3-16 to 3-18 below, wherein the voltage controlled switch comprises a MOSFET and a power supply.

[0302] 3-16: The RIP device of any one or a combination of one or more of 3-1 to 3-15 above and / or 3-17 to 3-18 below, wherein the power supply has a voltage of 0.6V.

[0303] 3-17: The RIP device of any one or a combination of one or more of 3-1 to 3-16 above and / or 3-18 below, wherein the power supply is a battery connected to the voltage controlled switch directly over a single DC-DC step-down converter.

[0304] 3-18: The RIP device of any one or a combination of one or more of 3-1 to 3-17 above, wherein the MOSFET is configured to operate primarily in the ohmic region when the MOSFET is conducting current.

[0305] 3-19: A method for capture and low power transmission of RIP signals using the Respiratory Inductive Plethysmograph (RIP) device of any one or a combination of one or more of 3-1 to 3-16 above, the method comprising: receiving an oscillating signal generated by an oscillator circuit, wherein the oscillating signal oscillates at a resonance frequency; amplifying an AC component of the oscillating signal to produce an amplified signal; and based on the amplified signal, producing an encoded output signal that indicates the resonance frequency of the amplified oscillating signal; and transmitting the encoded output signal, wherein producing an encoded output signal comprises: sampling the amplified signal to produce a first sample and a second sample, comparing the second sample to the first sample, after comparing, reducing the size of the second sample such that the second sample consumes less power to transmit than the first sample.

[0306] 3-20: The method according to any one or a combination of one or more of method 3- 19 above and / or 3-21 to 3-22 below, wherein the first sample has a size of 32 bits and the second sample, after reducing the size of the second sample, has a size of 8 bits.

[0307] 3-21: The method according to any one or a combination of one or more of methods 3-19 to 3-20 above and / or 3-22 below, wherein comparing the second sample to the first sample comprises checking whether the second sample is within a predetermined delta of the first sample.

[0308] 3-22: The method according to any one or a combination of one or more of methods3-19 to 3-21 above, wherein the predetermined delta is in the range from -64 to 63.

[0309] 3-23: A hardware storage device having stored thereon computer executable instructions which, when executed by one or more processors of a computer system, configure the computer system to perform the method according to any one or a combination of one or more of methods 3-19 to 3-22 above.

[0310] Group 4 - Respiratory Inductive Plethysmograph (RIP) devices with electrically conductive terminals and Methods

[0311] Methods, Devices, and Systems for a low power Respiratory Inductive Plethysmograph (RIP) devices with electrically conductive terminals.

[0312] 4-1: A Respiratory Inductive Plethysmograph (RIP) device comprising: one or more electrically conductive terminals configured to receive an oscillating signal; an amplifier circuit connected to the one or more electrically conductive terminals, wherein the amplifier circuit is configured to receive as an input an AC component of the oscillator signal and to output an amplifier output signal based on the AC component of the oscillator signal, and a voltage controlled switch connected to the one or more electrically conductive terminals and to the amplifier circuit, wherein the voltage controlled switch is configured to receive the amplifier output signal as an input and to output current to the one or more electrically conductive terminals.

[0313] 4-2: The RIP device of any one or a combination of one or more of 4-1 above and / or4-3 to 4-15 below, wherein the RIP device further comprises a comparator connected to the amplifier circuit, wherein the comparator is configured to receive the amplifier output signal.

[0314] 4-3: The RIP device of any one or a combination of one or more of 4-1 to 4-2 above and / or 4-4 to 4-15 below, wherein the RIP device further comprises an offset voltage controller configured to provide a DC bias to the amplifier output signal at the voltage controlled switch.

[0315] 4-4: The RIP device of any one or a combination of one or more of 4-1 to 4-3 above and / or 4-5 to 4-15 below, wherein the amplifier circuit amplifies signals that have frequencies in the range from 200kHz to 500kHz.

[0316] 4-5: The RIP device of any one or a combination of one or more of 4-1 to 4-4 above and / or 4-6 to 4-15 below, wherein the amplifier circuit has a phase shift of 360 degrees for signals that have frequencies in the range from 200kHz to 500kHz.

[0317] 4-6: The RIP device of any one or a combination of one or more of 4-1 to 4-5 above and / or 4-7 to 4-15 below, wherein the amplifier circuit dampens all DC signals from its input to its output.

[0318] 4-7: The RIP device of any one or a combination of one or more of 4-1 to 4-6 above and / or 4-8 to 4-15 below, wherein the offset voltage controller is configured to provide a selectable bias voltage in the range from 0.1V to 1.5V.

[0319] 4-8: The RIP device of any one or a combination of one or more of 4-1 to 4-7 above and / or 4-9 to 4-15 below, wherein the RIP device further comprises a kick circuit configured to start oscillations within the oscillator circuit.

[0320] 4-9: The RIP device of any one or a combination of one or more 4-1 to 4-8 above and / or 4-10 to 4-15 below, wherein the voltage controlled switch comprises a MOSFET and a power supply.

[0321] 4-10: The RIP device of any one or a combination of one or more of 4-1 to 4-9 above and / or 4-11 to 4-15 below, wherein the power supply has a voltage of 0.6V.

[0322] 4-11: The RIP device of any one or a combination of one or more of 4-1 to 4-10 above and / or 4-12 to 4-15 below, wherein the power supply is a battery connected to the voltage controlled switch directly over a single DC-DC step-down converter.

[0323] 4-12: The RIP device of any one or a combination of one or more of 4-1 to 4-12 above and / or 4-15 below, wherein the MOSFET is configured to operate primarily in the ohmic region when the MOSFET is conducting current.

[0324] 4-13: The RIP device of any one or a combination of one or more of 4-1 to 4-12 above and / or 4-14 to 4-15 below, wherein the RIP device comprises a housing, wherein the amplifier circuit, the voltage controlled switch, the comparator, and / or the offset voltage controller, and / or any combination thereof, are disposed within the housing.

[0325] 4-14: The RIP device of any one or a combination of one or more of 4-1 to 4-13 above and / or 4-14 to 4-15 below, wherein the one or more electrically conductive terminals are disposed on an exterior surface of the housing.

[0326] 4-15: The RIP device of any one or a combination of one or more of 4-1 to 4-14 above, wherein the one or more electrically conductive terminals are snap connectors.

[0327] 4-16: A method for capture and low power transmission of RIP signals using the Respiratory Inductive Plethysmograph (RIP) device of any one or a combination of one or more of 4-1 to 4-15 above, the method comprising: receiving an oscillating signal generated by an oscillator circuit, wherein the oscillating signal oscillates at a resonance frequency; amplifying an AC component of the oscillating signal to produce an amplified signal; and based on the amplified signal, producing an encoded output signal that indicates the resonance frequency of the amplified oscillating signal; and transmitting the encoded output signal, wherein producing an encoded output signal comprises: sampling the amplified signal to produce a first sample and a second sample, comparing the second sample to the first sample, after comparing, reducing the size of the second sample such that the second sample consumes less power to transmit than the first sample.

[0328] 4-17: The method according to any one or a combination of one or more of method 4- 16 above and / or 4-18 to 4-19 below, wherein the first sample has a size of 32 bits and the second sample, after reducing the size of the second sample, has a size of 8 bits.

[0329] 4-18: The method according to any one or a combination of one or more of methods 4-16 to 4-17 above and / or 4-19 below, wherein comparing the second sample to the first sample comprises checking whether the second sample is within a predetermined delta of the first sample.

[0330] 4-19: The method according to any one or a combination of one or more of methods 4-16 to 4-18 above, wherein the predetermined delta is in the range from -64 to 63.

[0331] 4-20: A hardware storage device having stored thereon computer executable instructions which, when executed by one or more processors of a computer system, configure the computer system to perform the method according to any one or a combination of one or more of methods 4-16 to 4-19 above.

[0332] Group 5 - Respiratory Inductive Plethysmograph (RIP) devices with a housing and Methods of Manufacture

[0333] Methods, Devices, and Systems for low power Respiratory Inductive Plethysmograph (RIP) devices with a housing.

[0334] 5-1: A Respiratory Inductive Plethysmograph (RIP) device comprising: one or more electrically conductive terminals configured to receive an oscillating signal; an amplifier circuit connected to the one or more electrically conductive terminals, wherein the amplifier circuit is configured to receive as an input an AC component of the oscillator signal and tooutput an amplifier output signal based on the AC component of the oscillator signal, and a voltage controlled switch connected to the one or more electrically conductive terminals and to the amplifier circuit, wherein the voltage controlled switch is configured to receive the amplifier output signal as an input and to output current to the one or more electrically conductive terminals, wherein the amplifier circuit and the voltage controlled switch are housed within a cutout area in a housing.

[0335] 5-2: The RIP device according to any one or a combination of 5-1 above and / or 5-3 to 5-7 below, wherein the housing has a three dimensional rectangular shape.

[0336] 5-3: The RIP device according to any one or a combination of 5-1 to 5-2 above and / or 5-4 to 5-7 below, wherein the housing has an x-dimension in the range from 35mm to 100mm, preferably in the range from 45mm to 90mm, more preferably in the range from 55mm to 80mm, more preferably in the range from 65mm to 75mm, more preferably in the range from 69mm to 71mm, and even more preferably 70.16mm.

[0337] 5-4: the RIP device according to any one or a combination of 5-1 to 5-3 above and / or 5-5 to 5-7 below, wherein the housing has a y-dimension in the range from 15mm to 45mm, preferably in the range from 20mm to 40mm, more preferably in the range from 25mm to 35mm, more preferably in the range from 30mm to 31mm, and even more preferably 30.86mm.

[0338] 5-5: The RIP device according to any one or a combination of 5-1 to 5-4 above and / or 5-6 to 5-7 below, wherein the housing has a z-dimension in the range from 5mm to 15mm, preferably in the range from 7mm to 13mm, more preferably in the range from 10mm to 12mm, and even more preferably 11.02mm.

[0339] 5-6: The RIP device according to any one or a combination of 5-1 to 5-5 above and / or 5-7 below, wherein the RIP device has a weight in the range from 3g to 69g, preferably in the range from 5g to 60g, more preferably in the range from 7g to 50g, more preferably in the range from 8g to 40g, more preferably in the range from 9g to 30g, more preferably in the range from 10g to 20g, and even more preferably in the range from 11g to 15g. In some particularly advantageous embodiments, the RIP device 2500 may weigh 12.5g.

[0340] 5-7: The RIP device according to any one or a combination of 5-1 to 5-6 above, wherein the RIP device has a weight in the range 4g to 69g, preferably in the range from 8g to 60g, more preferably in the range from 12g to 50g, more preferably in the range from 15g to 40g, more preferably in the range from 16g to 30g, more preferably in the range from 17g to 20g, and even more preferably in the range from 18g to 19.5g. In some particularlyadvantageous embodiments, the RIP device 2600, the connecting wire 2640, and the RIP device 2650 may have a combined weight of 19g.

[0341] 5-6: A method of manufacturing a RIP device according to any one or a combination of 5-1 to 5-5 above, comprising: producing one or more electrically conductive terminals; producing an amplifier circuit; producing a voltage controlled switch; connecting the one or more electrically conductive terminals to the amplifier circuit and to the voltage controlled switch; connecting the amplifier circuit to the voltage controlled switch; producing a housing with a cutout area; and disposing the amplifier circuit, the amplifier circuit and the voltage controlled switch within the cutout area in the housing.

[0342] Group 6 - Low Power Respiratory Inductive Plethysmograph (RIP) devices with an energy preserving power source

[0343] Methods, Devices, and Systems for low power Respiratory Inductive Plethysmograph (RIP) devices with an energy preserving power source.

[0344] 6-1: A Respiratory Inductive Plethysmograph (RIP) device comprising: an oscillator circuit comprising an inductor from a RIP sensor and a capacitor, wherein the oscillator circuit is configured to generate an oscillator signal; an amplifier circuit connected to the oscillator circuit, wherein the amplifier circuit is configured to receive as an input an AC component of the oscillator signal and to output an amplifier output signal based on the AC component of the oscillator signal; and a voltage controlled switch connected to the oscillator circuit and to the amplifier circuit, wherein the voltage controlled switch is configured to receive the amplifier output signal as a control input and when in a closed configuration, to conduct current from an energy preserving power source to the oscillator circuit.

[0345] 6-2: The RIP device according to any one or a combination of 6-1 above and / or 6-3 to 6-19 below, wherein the energy preserving power source is a step-down converter and / or a step-down regulator that is synchronized with the oscillator signal and / or harmonics of the oscillator signal.

[0346] 6-3: The RIP device according to any one or a combination of 6-1 to 6-2 above and / or 6-4 to 6-19 below, wherein the RIP device further comprises an offset voltage controller configured to provide a selectable DC bias to the amplifier output signal at the voltage controlled switch.

[0347] 6-4: The RIP device according to any one or a combination of 6-1 to 6-3 above and / or 6-5 to 6-19 below, wherein the oscillator circuit, the amplifier circuit, and the voltage controlled switch are connected in a feedback loop such that the oscillator circuit, the amplifier circuit, and the voltage controlled switch all operate at a same frequency.

[0348] 6-5: The RIP device according to any one or a combination of 6-1 to 6-4 above and / or 6-6 to 6-19 below, wherein the oscillator circuit further comprises a series inductor in series with the inductor from the RIP sensor.

[0349] 6-6: The RIP device according to any one or a combination of 6-1 to 6-5 above and / or 6-7 to 6-19 below, wherein the series inductor has a fixed inductance in the range from 0.1 pH to 7pH and the inductor has an inductance in a range from 0.5pH to 7pH

[0350] 6-7: The RIP device according to any one or a combination of 6-1 to 6-6 above and / or 6-8 to 6-19 below, wherein the series inductor has a variable inductance.

[0351] 6-8: The RIP device according to any one or a combination of 6-1 to 6-7 above and / or 6-9 to 6-19 below, wherein the inductor of the oscillator circuit comprises a RIP belt.

[0352] 6-9: The RIP device according to any one or a combination of 6-1 to 6-8 above and / or 6-10 to 6-19 below, wherein the oscillator circuit further comprises a transformer through which the oscillator circuit is connected to the amplifier circuit and the voltage controlled switch.

[0353] 6-10: The RIP device according to any one or a combination of 6-1 to 6-9 above and / or 6-11 to 6-19 below, wherein the amplifier circuit amplifies signals that have frequencies in a range from 200kHz to 500kHz, and wherein the amplifier circuit has a phase shift of 360 degrees for signals that have frequencies in a range from 200kHz to 500kHz.

[0354] 6-11: The RIP device according to any one or a combination of 6-1 to 6-10 above and / or 6-12 to 6-19 below, wherein the offset voltage controller is configured to provide a selectable bias voltage in a range from 0.1V to 1.5 V.

[0355] 6-12: The RIP device according to any one or a combination of 6-1 to 6-11 above and / or 6-13 to 6-19 below, wherein the RIP device further comprises a kick circuit configured to start oscillations within the oscillator circuit.

[0356] 6-13: The RIP device according to any one or a combination of 6-1 to 6-12 above and / or 6-14 to 6-19 below, wherein the voltage controlled switch comprises a MOSFET.

[0357] 6-14: The RIP device according to any one or a combination of 6-1 to 6-13 above and / or 6-15 to 6-19 below, wherein the energy preserving power source has a voltage in the range from 0.1V to 2.9V.

[0358] 6-15: The RIP device according to any one or a combination of 6-1 to 6-14 above and / or 6-16 to 6-19 below, wherein the energy preserving power source a single DC-DC stepdown converter connected to the voltage controlled switch on one side and a battery on the other side.

[0359] 6-16: The RIP device according to any one or a combination of 6-1 to 6-15 above and / or 6-17 to 61-19, wherein the MOSFET is configured to operate primarily in an ohmic region when the MOSFET is conducting current.

[0360] 6-17: The RIP device according to any one or a combination of 6-1 to 6-16 above and / or 6-18 to 6-19 below, wherein the energy preserving power source is a step-down regulator that is synchronized with the oscillator signal.

[0361] 6-18: The RIP device according to any one or a combination of 6-1 to 6-17 above and / or 6-19 below, wherein the energy preserving power source is a step-down regulator that is configured to operate at frequencies that are an integer multiple and / or an integer division of a frequency of the oscillator signal.

[0362] 6-19: The RIP device according to any one or a combination of 6-1 to 6-18 above, wherein the amplifier circuit is configured to amplify signals in an operating frequency range of the oscillator circuit and to attenuate signals outside of the operating frequency range.

[0363] 6-20: A method for capture and low power transmission of RIP signals using the Respiratory Inductive Plethysmograph (RIP) device of claim 1, the method comprising: receiving an oscillating signal generated by an oscillator circuit, wherein the oscillating signal oscillates at a resonance frequency; amplifying an AC component of the oscillating signal to produce an amplified signal; and based on the amplified signal, producing an encoded output signal that indicates the resonance frequency of the amplified signal; and transmitting the encoded output signal, wherein producing the encoded output signal comprises: sampling the amplified signal to produce a first sample and a second sample, comparing the second sample to the first sample, after comparing, reducing a size of the second sample such that the second sample consumes less power to transmit than the first sample.

[0364] 6-21: The method according to any one or a combination of 6-20 above and / or 6-22 to 6-23 below, wherein the first sample has a size of 32 bits and the second sample, after reducing the size of the second sample, has a size of 8 bits.

[0365] 6-22: The method according to any one or a combination of 6-20 to 6-21 above and / or 6-23 below, wherein comparing the second sample to the first sample comprises checking whether the second sample is within a predetermined delta of the first sample.

[0366] 6-23: The method according to any one or a combination of 6-20 to 6-22 above, wherein the predetermined delta is in a range from -64 to 63.

Claims

CLAIMS:

1. A Respiratory Inductive Plethysmograph (RIP) device comprising: an oscillator circuit comprising an inductor from a RIP sensor and a capacitor, wherein the oscillator circuit is configured to generate an oscillator signal; an amplifier circuit connected to the oscillator circuit, wherein the amplifier circuit is configured to receive as an input an AC component of the oscillator signal and to output an amplifier output signal based on the AC component of the oscillator signal; and a voltage controlled switch connected to the oscillator circuit and to the amplifier circuit, wherein the voltage controlled switch is configured to receive the amplifier output signal as a control input and, when in a closed configuration, to conduct current from an energy preserving power source to the oscillator circuit.

2. The RIP device of claim 1, wherein the energy preserving power source is a step-down regulator that is synchronized with the oscillator signal or is configured to operate at frequencies that are an integer multiple or an integer division of a frequency of the oscillator circuit.

3. The RIP device of claim 1, wherein the RIP device further comprises an offset voltage controller configured to provide a selectable DC bias to the amplifier output signal at the voltage controlled switch.

4. The RIP device of claim 1 , wherein the oscillator circuit, the amplifier circuit, and the voltage controlled switch are connected in a feedback loop such that the oscillator circuit, the amplifier circuit, and the voltage controlled switch all operate at a same frequency.

5. The RIP device of claim 1, wherein the oscillator circuit further comprises a series inductor in series with the inductor from the RIP sensor.

6. The RIP device of claim 5, wherein the series inductor has a fixed inductance in a range from O.lpH to 7pH and the inductor from the RIP sensor has an inductance in a range from 0.5pH to 7pH.

7. The RIP device of claim 5, wherein the series inductor has a variable inductance.

8. The RIP device of claim 5, wherein the inductor of the oscillator circuit comprises a RIP belt.

9. The RIP device of claim 1, wherein the oscillator circuit further comprises a transformer through which the oscillator circuit is connected to the amplifier circuit and the voltage controlled switch.

10. The RIP device of claim 1, wherein the amplifier circuit is configured to amplify signals in an operating frequency range of the oscillator circuit and to attenuate signals outside of the operating frequency range.

11. The RIP device of claim 3, wherein the offset voltage controller is configured to provide a selectable bias voltage in a range from 0.1V to 1.5 V.

12. The RIP device of claim 1, wherein the RIP device further comprises a kick circuit configured to start oscillations within the oscillator circuit.

13. The RIP device of claim 1, wherein the voltage controlled switch comprises a MOSFET.

14. The RIP device of claim 13, wherein the energy preserving power source is configured to provide a voltage in a range from 0.1V to 2.9V.

15. The RIP device of claim 13, wherein the energy preserving power source is a single DC- DC step-down converter through which the voltage controlled switch is connected to a battery.

16. The RIP device of claim 13, wherein the MOSFET is configured to operate primarily in an ohmic region when the MOSFET is conducting current.

17. A method for capture and low power transmission of RIP signals using the Respiratory Inductive Plethysmograph (RIP) device of claim 1, the method comprising: receiving an oscillating signal generated by an oscillator circuit, wherein the oscillating signal oscillates at a resonance frequency; amplifying an AC component of the oscillating signal to produce an amplified signal; based on the amplified signal, producing an encoded output signal that indicates the resonance frequency of the amplified signal; and transmitting the encoded output signal, wherein producing the encoded output signal comprises: sampling the amplified signal to produce a first sample and a second sample, comparing the second sample to the first sample, andafter comparing, reducing a size of the second sample such that the second sample consumes less power to transmit than the first sample.

18. The method of claim 17, wherein the first sample has a size of 32 bits and the second sample, after reducing the size of the second sample, has a size of 8 bits.

19. The method of claim 17, wherein comparing the second sample to the first sample comprises checking whether the second sample is within a predetermined delta of the first sample.

20. The method of claim 19, wherein the predetermined delta is in a range from -64 to 63.

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