Photodetector system with low-power time digital converter architecture

Abstract

To provide photodetector systems with low-power time-to-digital converter architectures.SOLUTION: A photodetector system includes: a photodetector 1024; and a TDC coupled to the photodetector. The TDC is configured to receive, during a predetermined event detection time window that commences in response to an application of a light pulse to a target, a signal triggered by an event in which the photodetector detects a photon of the light pulse after the light pulse reflects from the target. The TDC is further configured to enable, in response to the receiving the signal, a gated ring oscillator (GRO) of the TDC, measure, using the GRO, a time interval between when the event occurred and an end of the predetermined event detection time window, and determine, based on the time interval and the predetermined event detection time window, an arrival time of the photon at the photodetector.SELECTED DRAWING: Figure 10B

Description

Related applications

[0001] This application is based on U.S. Provisional Patent Application No. 62 / 906,620, filed on September 26, 2019. The superiority of the U.S. Provisional Patent Application No. 62 / 858,029, filed on June 6, 2019. Priority is claimed. These applications are incorporated herein by reference in their entirety. ru. [Background technology]

[0002] Detecting neural activity in the brain is used in medical diagnosis, imaging, neuroengineering, and brain computing. It is useful for interface integration and various other diagnostic and consumer-related applications. Yes. For example, certain areas of the brain may be affected by reduced blood flow, bleeding, or any other type of damage. When determining whether a region has been affected, it is desirable to detect neural activity in the patient's brain. This may occur. As another example, the neural activity in the user's brain is detected, and the detected neural activity Decode it computerically (for example, to control the cursor on the computer screen, Various types of home appliances (such as changing TV channels or turning on lights) It may be desirable to make it a command that can be used to control it.

[0003] A photodetector capable of detecting a single photon (i.e., a single particle of light energy) is used in the neural network of the brain. This is one example of a non-invasive detector that can be used to detect activity. For example, these Many highly sensitive photodetectors reflect light in brain tissue in response to the application of one or more light pulses. The photons that are detected can be recorded. Brain neural activity and other characteristics are required for the photodetector to detect the photons. It can be determined or estimated based on time.

[0004] A time-to-digital converter (TDC) is used in conjunction with a photodetector. And, a timing event or timing interval (for example, when a pulse of light is applied to a target) The time required to detect the photons of the light pulse using a photodetector is then converted into a digital representation. To replace. Conventionally, phase-locked loops or delay-locked loops are used to replace phase and delay information. It has provided information and captured digitized values ​​with a specific timing resolution. However Therefore, a relatively large amount of power is used when synchronizing the TDC and / or components of the TDC. It can be consumed. [Brief explanation of the drawing]

[0005] [Figure 1] This figure shows an example of a photodetector with a low-power TDC architecture based on the principles described herein. [Figure 2] This figure shows an example of a photodetector system with a low-power TDC architecture based on the principles described herein. [Figure 3] This is an illustrative timing diagram for a photodetector with a low-power TDC architecture based on the principles described herein. [Figure 4] This figure shows an exemplary circuit for a component of a low-power TDC architecture based on the principles described herein. [Figure 5] This figure shows an exemplary circuit for a component of a low-power TDC architecture based on the principles described herein. [Figure 6] This figure shows an exemplary circuit for a component of a low-power TDC architecture based on the principles described herein. [Figure 7] This figure shows an exemplary circuit for a component of a low-power TDC architecture based on the principles described herein. [Figure 8]A diagram showing an exemplary circuit for components of a low-power TDC architecture according to the principles described herein. [Figure 9] Figures 9A and 9B are diagrams showing an example of a photodetector system with a low-power TDC architecture according to the principles described herein. [Figure 10A] A diagram showing an example of a photodetector system with a low-power TDC architecture according to the principles described herein. [Figure 10B] A diagram showing an exemplary wearable device comprising a photodetector system with a low-power TDC architecture according to the principles described herein. [Figure 11] A diagram showing an exemplary method according to the principles described herein. [Figure 12] A diagram showing an exemplary computer device according to the principles described herein.

[0006] The accompanying drawings, which are a part of this specification, illustrate various embodiments. The illustrated embodiments are merely examples and do not limit the scope of the disclosure. Throughout the drawings, the same or similar reference numerals designate the same or similar elements. Detailed description forms are merely illustrative and do not limit the scope of the present disclosure. Throughout the drawings, the same or similar reference numerals identify the same or similar elements. Detailed description One or similar reference numbers specify the same or similar elements. Detailed description

[0007] This specification describes a photodetector system with a low-power TDC architecture. The system described herein comprises a photodetector, a TDC connected to the photodetector, and a control circuit following the TDC. The TDC is a signal triggered by an event that detects photons of the optical pulse after the optical pulse is reflected from the target during a predetermined event detection time window that starts in response to the application of the optical pulse to the target, and is configured to enable the gated ring oscillator (GRO) of the TDC. subsequent control circuit. The TDC is a signal triggered by an event that detects photons of the optical pulse after the optical pulse is reflected from the target during a predetermined event detection time window that starts in response to the application of the optical pulse to the target, and is configured to enable the gated ring oscillator (GRO) of the TDC. in the target, and after the optical pulse is reflected from the target, the photons of the optical pulse are detected by the photodetector, and the signal is triggered by the event, and the gated ring oscillator (GRO) of the TDC is configured to be enabled. detector, and is triggered by an event that detects photons of the optical pulse after the optical pulse is reflected from the target during a predetermined event detection time window that starts in response to the application of the optical pulse to the target, and is configured to enable the gated ring oscillator (GRO) of the TDC. ring oscillator (GRO) of the TDC. configured to receive a signal. The TDC is further configured to use the GRO to measure the time interval between the occurrence of an event and the end of a predetermined event detection time window. The control circuit is configured to determine the arrival time of photons at the photodetector based on the time interval and the predetermined event detection time window.

[0008] The TDC architecture described herein enables the GRO and / or other components of the TDC in response to an event in which photons are detected. Thus, the TDC architecture can be power-saving until such an event occurs. In a photodetector system having a plurality of photodetectors, many of the photodetectors detect photons relatively infrequently. Therefore, according to such an event-driven TDC architecture, the power consumption can be significantly reduced as compared with a conventional photodetector system. Further, since the TDC is disabled and enabled, components that have conventionally been used to synchronize a plurality of TDCs are unnecessary. As a result, not only does the system area decrease, but the power consumption is further reduced. The above-described advantages and / or advantageous points and other advantages and / or advantageous points that can be provided by the systems and methods described herein will become apparent from the following detailed description. FIG. 1 shows an example of a photodetector system 102 having a low-power TDC architecture. As shown in the figure, the photodetector system 102 includes a photodetector 104, a control circuit 106, and a TDC 108. In some examples, the photodetector system 102 includes more components, fewer components, and / or different components.

[0009] FIG. 1 shows an example of a photodetector system 102 having a low-power TDC architecture. As shown, the photodetector system 102 includes a photodetector 104, a control circuit 106, and a TDC 108. In some examples, the photodetector system 102 includes more components, fewer components, and / or different components. components, fewer components, and / or different components.​​​​​​ For example, the photodetector system 102 may include multiple photodetectors and multiple corresponding photodetectors. The system may include several TDCs, a photodetector, and one or more control circuits for the TDCs.

[0010] The photodetector 104 is configured to detect each photon of light incident on the photodetector 104 individually. It can be implemented by any suitable circuit. For example, the photodetector 104 is a single It works together with the photon avalanche diode (SPAD) to process the photons incident on the SPAD. This can be implemented using a SPAD circuit with a high-speed gate circuit configured for detection. Yes, it is possible. The photodetector 104 may generate an output when the SPAD detects a photon.

[0011] TDC108 detects that a certain light pulse has occurred and that this light pulse has been reflected from the target. After the light pulse is detected, the photon from the light pulse is detected by the SPAD circuit 104. It is configured to measure the time difference between the generation of the output signal generated by the output device 104 and the generation of the output signal. This specification describes an implementation example of TDC108.

[0012] The control circuit 106 is an application-specific integrated circuit (ASIC) or a photodetector 104 (for example) To control the operation of the SPAD circuit and various components within the TDC108 It can be implemented by any other suitable circuit configuration.

[0013] For example, the control circuit 106 controls the operation of one or more switches in the SPAD circuit. It outputs control logic to selectively charge the capacitor in the SPAD circuit (for example, (By doing so) the SPAD equipped with the photodetector 104 is selectively put into an armed state or It can be set to either the disarmed state. In some examples, the control cycle Path 106 is where the control circuit 106 waits after the generation of an optical pulse (for example, a laser pulse). The gate delay that activates the SPAD may be controlled by specifying a fixed time. Therefore, the control circuit 106 determines the timing at which the light pulse is generated (for example, when the light pulse is present in brain tissue, etc.) The system may receive optical pulse timing information (such as the time at which the pulse is applied to the target). The path 106 may also control a programmable gate width. Depending on the gate width, SP The duration of the operating state that should be maintained before the AD is released is specified. For example, control circuit 1 06 may keep SPAD operational during a specific event detection time window.

[0014] The control circuit 106 may also be configured to control the operation of the TDC 108. Example For example, as described herein, the control circuit 106 controls the GRO and in TDC108. Used to enable and / or disable other components. One or more signals may be generated.

[0015] The control circuit 106 sends one or more signals to the data output by TDC108. It may be further configured to perform signal processing operations. For example, the signal processing circuit 110 may perform T Based on the data output by DC108, and accessed by the control circuit 106 The histogram parameters (e.g., time bin, number of light pulses, type of histogram) Histogram data may be generated according to the following (etc.). For example, control circuit 106 Based on the data output by TDC108, a histogram is generated, saved, and transmitted. Compression, analysis, decoding, and / or other processing may be performed. Some examples include... Furthermore, signal processing operations may be performed by other additional components.

[0016] Figure 2 shows an example of a photodetector system 200 with a low-power TDC architecture. The detector system 200 includes photodetector pixels 202 (for example, photodetector pixels 1 and 20 It is equipped with photodetector pixels N (202-N) from 2-1. Each photodetector pixel 202 is equipped with a SPAD circuit 204 and a TDC 206. The TDC206 consists of the GRO208, the counter 210, and the bias generator 212. Prepare. The bias generator 212 receives a signal from the phase-locked loop (PLL) 214. This is possible. The photodetector system 200 is (for example, an implementation example of the control circuit 106) The control circuit 216 further comprises a control circuit 216 and a memory 218. It supports photodetector pixel 202.

[0017] (For example, the SPAD circuit 204, which is an implementation example of the photodetector 104, consists of SPAD and SP It includes a high-speed gate circuit configured to arm and disarm the AD. It may also be triggered by an event in which the SPAD detects a photon. It may be configured to output a signal that has been received by TDC206. In this configuration, the GRO of the TDC206 is enabled. For example, GRO2 08 may be enabled based on the reception of a signal from the SPAD circuit 204. DC206 connects GRO208 (counter 210 and / or bias generator 212) (In conjunction with any other component) you can use this to determine the arrival time of photons at SPAD. For example, TDC206 uses photons based on the exemplary timing diagram 300 shown in Figure 3. The arrival time may also be determined.

[0018] Timing diagram 300 shows the first predetermined event detection time window 304-1 (length "c") and a second predetermined event detection time window 304-2 and other predetermined event detection time windows 304 The event window pulse wave 302 indicates the event window. The predetermined event detection time window 304 marks the target. A predetermined event can be generated by the control circuit 216 in response to the applied light pulse. The photon detection time window 304 is used when the SPAD is activated and enabled to detect photons of the light pulse. It may correspond to each of the lengths of time. The predetermined event detection time window 304 is individually It may be started following the light pulse. As described above, in some examples, a predetermined The vent detection time window 304 may start after a specific delay following each individual light pulse. In this example, the predetermined event detection time window 304 opens substantially immediately after each individual light pulse. It can also be used from the start.

[0019] The event pulse wave 306 indicates event 308, in which the SPAD circuit 204 detects a photon. As shown in the figure, event 308 is within the first predetermined event detection time window 304-1 It occurs inside. Event 308 is output by SPAD circuit 204 to TDC206. The more frequently received signals may be used as triggers. Based on the reception of the signal, the GRO208 will The event 308 occurs and the first predetermined event detection time window 304-1 ends. The time interval between events may be measured. The time interval is the event of the event measurement pulse wave 310. The timing is shown by measurement 312 (length "a"). The timing diagram 300 is for GRO208. Further, a counter pulse wave 318 is generated that shows the value of the counter 210 corresponding to the determined measurement. Includes. For example, the first count 320 corresponds to event measurement 312 and time interval "a" A digital value C proportional to a It provides. Therefore, TDC206 is C a and the first predetermined Based on the known length "c" of the event detection time window 304-1, light in event 308 The arrival time of the child can be determined, and the determined arrival time corresponds to (ca).

[0020] In addition, timing diagram 300 shows a calibration measurement pulse wave indicating a calibration measurement 316 of length "b". Includes 314. Calibration value 316 is measured using GRO208 and event 308 A calibration element may be obtained to determine the arrival time of the photon. For example, TDC206 is G RO208 may be used to measure the calibration window that may be generated by the control circuit 216. The unta pulse wave 318 corresponds to the second count 3 of the counter 210 corresponding to the calibration measurement 316. It shows 22. The second count 322 is a digital value C proportional to the time interval "b". b Provide Yes. TDC206 is C b Using this, the GRO208 was calibrated, and further C b Based on The arrival time of the photon at vent 308 can also be determined. For example, TDC206 can be determined as follows: The arrival time may be determined based on equation 1.

[0021]

number

[0022] An example of the timing of such signals is shown in timing diagram 300, TDC 206 can be implemented as an event-based TDC, and / or TDC206 is It may also include venting components. For example, a photodetector system 200 (for example, control Circuit 216, TDC206) will disable GRO208 until event 308 occurs. It is fine to keep it on the cable (and / or TDC206 is disabled by GRO208) (This is also fine), and this is especially useful for applications where the frequency of events is relatively low. Power saving is possible. The photodetector system 200 is triggered by event 308. When a signal is received from the SPAD circuit 204, the GRO208 is enabled, and the event The arrival time of the photon at T308 may be determined using GRO208. Following that determination... The photodetector system 200 is triggered by the detection and / or calibration measurement of photons. You may disable the GRO208 until another event. Additionally or as an alternative, The photodetector system 200 keeps the GRO208 enabled and calibrates the GRO208. Such calibration measurements may be performed after each event measurement for a certain number of events. After that, it may be performed at any suitable frequency, such as after a certain amount of time has elapsed since the previous calibration. stomach.

[0023] In some examples, the PLL21 provides the course count to the bias generator 212. While 4 provides the signal, GRO208 is used to fine-tune the timing of event 308. A fine count may be determined. The PLL214 is locked to an external reference clock. Alternatively, an analog voltage may be provided to the bias generator 212. In other examples, the photodetector Stem 200 is implemented without using PLL 214 and / or bias generator 212. It may be so. In such an example, the GRO208 may be self-propelled, and digital rice The start and end may be determined by cable signals. An example of GRO208 is described herein. do.

[0024] Figure 4 shows circuit 400 as an example of implementing a bias generator (for example, bias generator 212). This shows that the circuit 400 is equipped with a reference current source 402, such as a reference value received from the PLL 214. Circuit 400 shows a current mirror that is gated by the enable signal 404. The cable signal 404 is event 30, which is an event in which the SPAD circuit 204 detects a photon. The analog signal provided in accordance with 8 may also be received. The enable signal 404 is received. Meanwhile, circuit 400 provides the first output PBIAS406 and the second to GRO208. The analog bias may be generated via the output NBIAS408. Conversely, enable While signal 404 is stopped, circuit 400 provides analog bias to GRO208. The service may be suspended.

[0025] Figure 5 shows the configuration to operate with a bias generator (e.g., bias generator 212). Circuit 500 is shown as an example of an inverter implementation for a GRO (e.g., GRO208). Circuit 500 receives a signal at input 502 and generates an inverted signal at output 504. The inverter is shown configured as follows. GRO208 has an output of 504 for one inverter. It is connected to the next inverter input 502 to form an inverter loop. Multiple inverters may be provided. Circuit 500 has a first input PBIAS506 and the The bias is received from the bias generator 212 via input 2, NBIAS508. The circuit 500 also shows a current-stirred inverter configured to pull Equipped with a down transistor 510, tristate output for inverter (e.g., high input) The pedance state is implemented. Furthermore, the pull-down transistor 510 is also part of circuit 5. Initialize to state 00 so that GRO208 can start in the same initialized state every time. It may be configured as follows.

[0026] While the analog bias is being received, the GRO208 oscillates and the counter (for example, The counter (210) is given a signal, and the counter records the digital time, such as the arrival time of the photon. It may be used to determine the expression. When the analog bias stops, the GRO208 will When disabled, the GRO208 inverter enters a high-impedance state. 08 is a component configured to store the value of GRO208, as shown in Figure 6. It may also be equipped with a T.

[0027] Figure 6 shows circuit 600 as an example of a GRO implementation (e.g., GRO208). Circuit 60 0 represents multiple stages 602 (for example, stages 602-1 to 602-N) As shown, each of the stages 602 in the diagram is connected to the next stage, Stage 602-N is also connected to Stage 602-1, forming a ring of Stage 602. That's fine.

[0028] Each stage 602, such as Stage 602-1, consists of one set of current studs. Inverter 604 (e.g., current-stirred inverters 604-1 and 604-2) ) is provided. The current-stirred inverter 604 is implemented by the circuit 500 in Figure 5. It is also possible. As mentioned above, the current-stirred inverter 604 takes a certain value as input. It receives the signal and provides its inverted value (for example, low to high or high to low) as output. Yes, it is possible. Furthermore, the current-stirred inverter 604 is a tri-state inverter. It may be present, and when the GRO208 is disabled, it outputs a high impedance state. It may be configured such that the GRO208 is disabled. When this happens, a set of cross-connected inverters configured to store the value of stage 602-1 It is further equipped with Ta606. In this way, the state of each stage 602, and by extension GRO208, The latched value may be internally latched by the cross-connected inverter 606. The minute counter value of TDC206 may be determined by doing so. GRO208 oscillates By disabling the GRO208 to stop the course counter (for example) The PLL214 can be gated without any additional circuitry.

[0029] Figure 7 shows an example of circuit 700 that implements another inverter for the GRO (e.g., GRO208). This shows that circuit 700 is an implementation of the current-stirred inverter 604 relative to circuit 600. This can also be used as an example. Similar to circuit 500, circuit 700 receives a signal at input 702. This shows an inverter configured to receive and generate an inverted signal at output 704. The inverter is also one of several inverters that are connected in a ring and implement the GRO208. It may be there. However, circuit 700 controls the on / off of the inverter, and by extension, the GRO208. A first input 706 configured to receive a digital enable signal to switch, The circuit 700 also includes a second input 708. Uh, in case the GRO208 is disabled, a tristate output (for example, high Implement the impedance state.

[0030] Circuit 700 operates autonomously without the need for an external PLL and / or bias generator. You may implement a GRO208 configured to do so. A GRO architecture that does not have such components is an architecture that does not have such components. In comparison, it is possible to reduce the layout area and power consumption. However, Without a feedback mechanism provided by an external PLL, the GRO208 (and Differences in processing, voltage, and temperature (PVT) between inverters (across multiple GROs) This can become more pronounced and may affect the measurements obtained by GRO208. However, By performing each calibration process as described in the specification, the impact of such differences is minimized. Alternatively, it can be offset.

[0031] Figure 8 shows an example of circuit 800 for a low-power TDC architecture. Circuit 800 is a photodetector This shows an implementation for determining the arrival time of events such as the detection of photons by an output device. Circuit 80 0 is equipped with GRO208. GRO208 is an event measurement (Ca Measurement corresponding to Output and calibration measurement value (C b ) provides a calibration output corresponding to. The calibration measurement value is received by the look-up table (LUT) component 802. The LUT component 802 receives the value for C b , searches for the value corresponding to 1 / C b , and provides 1 / C as the output to the multiplication b component 804. The multiplication component 804 receives 1 / C b from the LUT component 802, receives Ca from GRO208, and multiplies these two input values. The product corresponding to C a / C b is provided to the bitwise inversion component 806, and the bitwise inversion component 806 performs an operation on 1 minus C a / C b to obtain the final result. The final result corresponds to the time of the event as defined by Equation 1 above. The circuit 800 shows an example implementation for computing Equation 1, but any suitable combination of components may be used to determine the same result. For example, each and / or all of the operations described herein may be performed using a look-up table. As an alternative

[0032] or in addition, the operations may be performed without using a look-up table, and the operations may be performed using components configured to perform multiplication and components configured to perform subtraction along with components configured to perform division. Further, the input may be processed to use the PLL for course locking . As an alternative or in addition, the operations may be performed without using a look-up table, and the operations may be performed using components configured to perform multiplication and components configured to perform subtraction along with components configured to perform division. The circuit 800 shows an example implementation for computing Equation 1, but any suitable combination of components may be used to determine the same result. For example, each and / or all of the operations described herein may be performed using a look-up table. As an alternative This reduces the impact of PVT variability and minimizes the potential range of calibration and event measurements. The complexity of calculations such as causing this may be reduced. In addition, or as an alternative, each GRO2 Perform initial trimming on 08 to set the operating frequency of GRO208, and between GROs The differences may be reduced. In addition, or as an alternative, LUT component 802 may be used. The system may be implemented using read-only memory (ROM) to reduce power consumption and area.

[0033] Figure 9A shows an example of a photodetector system 900 having a low-power TDC architecture. The photodetector system 900 includes a pixel array 902, and the pixel array 902 is a pixel Includes subarray 904 (e.g., pixel subarrays 904-1 and 904-2). Xel subarray 904 is an event (e.g., photon detection by pixels within the subarray) And signals corresponding to event windows (e.g., predetermined event detection time windows) are transmitted to multiple GRs. Output to O906. For example, the pixel subarray 904-1 contains the first event and the second The signal corresponding to one event window is sent to the first GRO of multiple GRO906 (and / or The output may be to a subset of the first GRO. Pixel subarray 904-2 is the second GRO Signals corresponding to the event and the second event window are sent to the second GRO of multiple GRO906s. The output may be to (and / or a subset of the second GRO). However, photodetection Depending on the distance between the partial array within the instrument system 900 and the corresponding GRO, the layout delay may occur. Delays may occur. Such layout delays can affect the timing of events. This may be inaccurate. The signal corresponding to the event window is sent along with the signal corresponding to the event. By outputting, the photodetector system 900 is configured to compensate for layout delay. It is possible.

[0034] For example, Figure 9B shows the timing for the photodetector system 900, which demonstrates the correction of layout delay. Figure 920 is shown. In this example, the first event and the second event are compared with each other. Because they can occur at very close intervals, these two times are grouped into the same time bin. It should be. However, due to layout delay, the second event pulse wave 924 and As illustrated by the first event pulse wave 928, the second event is the first event It may be received by the GRO906 earlier than the vent. A message will appear in the corresponding event window. By providing the number, the photodetector system 900 detects events relative to the event window. The timing can be determined and the layout delay can be offset, as shown in Timing Diagram 920. The second event window pulse wave 922 is the first event window pulse wave 926 This shows the second event window that arrives earlier than the first event window. The difference in the arrival times of the event windows is... By taking, or by determining the timing of events in the event window This can compensate for such layout delays.

[0035] Furthermore, the photodetector system described herein is a SPAD circuit or a SPAD circuit Since it has TDC for a subset, it is functional for such photodetector systems. The test process may be improved. Multiple TDCs may be used to test some of the SPAD circuits. This makes it possible to perform tests on all aspects simultaneously and / or in parallel, and the system The dark count rate during startup and / or yield testing of mass production is measured by a photodetector system. It becomes possible to re-test.

[0036] Figure 10A shows a photodetector system that can be used according to the systems and methods described herein. An example of M1000 is shown. The photodetector system 1000 is a photodetector system as described herein. Either of the above may be implemented. As shown in the figure, the photodetector system 1000 is a print A light source 1002 and multiple SPAD circuits 1004 are arranged on a PCB (PCB) 1006. (That is, it includes SPAD circuits 1004-1 to 1004-16). Alternatively, S PAD circuit 1004 (and other components of photodetector system 1000) are AS It may be placed on an IC. The photodetector system 1000 is a control common to SPAD1004. Circuit 1008, signal processing circuit 1010 common to each SPAD 1004, and SPAD circuit Multiple TDs (as described herein) corresponding to each of the roads 1004 It further comprises a TDC array 1012 including C, a control circuit 1008, and a signal processing circuit 1010. The TDC array 1012 and the TDC array 1012 are arranged on PCB 1006, respectively, as shown in Figure 10A. Each SP may be placed in one location or installed elsewhere within the photodetector system 1000. The AD circuit 1004 is provided with a TDC in the TDC array 1012, a control circuit 1008, and A specific photodetector may be implemented in combination with the signal processing circuit 1004. The detector system 1000 can be said to comprise an array of photodetectors.

[0037] The light source 1002 emits one or more waves applicable to a desired target (e.g., a target in the brain). The light source 1002 may be configured to generate one or more light pulses in length. It may be implemented by any suitable combination of components. For example, light source 10 02 may be implemented by a laser source that generates laser pulses. The light source is PCB10 It may be implemented on 06, or it may be implemented outside of PCB1006.

[0038] The SPAD circuit 1004 processes the photons of the light pulse generated by the light source 1002. Detected after being reflected or scattered by the target (e.g., an internal target of the user, such as brain tissue). It may be configured to use the SPAD circuit 1004 for imaging applications. Photons reflected from any object due to ambient light may be detected. In this case, Since photons are generated by either ambient light or another light source, light source 1002 is not required. ru.

[0039] As shown in the figure, the SPAD circuit 1004 is arranged in a 4x4 array on PCB 1006. The positioning of each SPAD circuit 1004 corresponds, for example, to a pixel in the pixel array. This may be done. The SPAD circuit 1004 may also be arranged in any preferred manner. Good. Figure 10A shows 16 SPAD circuits 1004, but the photodetector system Please understand that any number of SPAD circuits 1004 may be provided in 1000.

[0040] Control circuit 1008 may be functionally similar to control circuit 106, and SPAD circuit 100 Each of the 8 may be configured to control the signal processing circuit 1010. The path 110 may be functionally similar, and each of the SPAD circuits 1004 outputs It may be configured to process signals. The TDC array 1012 is such that each of them is TDC10 It has multiple TDCs similar to 8, for generating the optical pulse 1002 and the SPAD circuit 1004 It is configured to measure the time difference between each of the output pulses generated by each of them. It's okay.

[0041] The photodetector system 1000 may be implemented by any suitable device, or It may be provided in any suitable device. For example, the photodetector system 1000 may be used A non-invasive wearable device that can be attached to the body is provided with one or more diagnostic functions. The system may perform imaging and / or consumer-related operations.

[0042] Specifically, Figure 10B shows an implementation of a photodetector system similar to the photodetector system 1000. A non-invasive wearable brain interface system 1020 ("brain interface") An example of the "Face System 1020" is shown. As illustrated, the brain interface System 1020 is a head-mountable component configured to be worn on the user's head. It includes component 1022. The head-mountable component 1022 is attached to the user's head. It can be implemented by the shape of the cap that is attached to it. Head-mountable component Alternative implementations of the 1022 include helmets, beanies, headbands, and other hat shapes. , or other shapes suitable for attachment to the user's head, etc. Head-mountable controller Ponent 1022 is suitable for any fabric, soft polymer, plastic, hard shell, and / or may be made from any other suitable material that can accommodate a particular implementation. Examples of headgear used in wearable brain interface systems can be found by referencing The entire details are further described in U.S. Patent No. 10,340,408, which is incorporated herein by reference. It is listed.

[0043] The head-mountable component 1022 includes multiple photodetectors 1024 and optical pulses It comprises multiple light sources 1026 configured to generate. In this configuration, the head-mountable component 1022 is a single photodetector 1024 It should be understood that the system may also include a single light source 1026. For example, The interface system 1020 is used to control the optical path and the photodetector pixels. The measured values ​​may be converted into intensity values ​​representing the optical properties of brain tissue regions. System 1020 uses photons generated from the light source 1026 to the target location in the user's brain. By extracting this data, optical examination of deep anatomical regions that penetrate the skin and bone can be performed. In terms of enabling the imaging of surface tissue structures or structures that are completely optically transparent, It differs from conventional imaging systems and methods (e.g., optical coherence tomography (OCT)).

[0044] The brain interface system 1020 connects to the photodetector via the communication link 1030. Communication with 1024 and light source 1026 (for example, from photodetector 1024 and light source 1026) The system further comprises a processor 1028 configured to control and / or receive signals. It may also be the case that the communication link 1030 is any suitable wired and / or wireless communication link. It may include. The processor 1028 may have any suitable enclosure, and optionally, It may be placed on the user's scalp, neck, shoulders, chest, or arms. In some variations, The processor 1028 is located in the same assembly housing as the photodetector 1024 and the light source 1026. It may be integrated into the group.

[0045] As shown in the figure, the brain interface system 1020 is a processor 1028 A remote processor 1032 that communicates with the remote processor may be optionally provided. For example, the remote processor Ssa1032 is from the previous detection session and / or a large number of brain interfaces Photodetector 1024 and / or processor 102 from the face system (not shown) The data measured from 8 may be stored. Photodetector 1024, light source 1026, and / Alternatively, power for the processor 1028 is supplied via a wearable battery (not shown). It may be done. In some examples, the processor 1028 and the battery are in a single enclosure. It may be housed in, and the wires that transmit power signals from the processor 1028 and the battery are It may extend to the photodetector 1024 and the light source 1026. Alternatively, the power is ( For example, it may be provided wirelessly (by induction).

[0046] In some other embodiments, the head-mountable component 1022 is It does not have a separate light source. Instead, it generates light that is detected by the photodetector 1024. A light source configured in this way is provided in another location within the brain interface system 1020. For example, the light source may be provided on the processor 1028, and the electrical connection may be It may also be connected to the photodetector unit 1024 through a connection.

[0047] Each of the light sources described herein may be implemented by any suitable device. For example, the light sources used herein include, for example, distributed feedback (DFB) lasers, superheterodyne lasers, etc. Luminescent diode (SLD), light-emitting diode (LED), diode-excited solid (DPSS) laser, semiconductor laser (LD), superluminescent light-emitting diode ( sLED), Vertical Cavity Surface Emitting Laser (VCSEL), Titanium Sapphire Laser, Microphone Light-emitting diodes (mLEDs), and / or any other suitable lasers or light sources. That's fine.

[0048] The photodetector system 1000 shown in Figure 10A is, or a non-wearable device ( For example, it may be placed near the user's head or other body parts to perform one or more diagnostic and imaging tasks. Medical devices and / or consumer-related devices that perform images and / or consumer-related operations. It may be provided in a vice. The photodetector system 1000 is, or a wearable intrusion Subassembly housing of an implantable medical device (e.g., an implantable medical device for recording and imaging the brain). It may be placed on the body.

[0049] Any suitable SPAD circuit can be used within the photodetector architecture described herein. It may also be possible. Some of the SPAD circuits described herein use commands to activate the SPAD. A capacitor that is pre-charged with a bias voltage before it is supplied (or, in some cases It is gated (by the parasitic capacity of the SPAD itself). This is because, by reference, the whole thing is first supported Further details are provided in U.S. Patent No. 10,158,038, which was used.

[0050] Figure 11 shows a photodetector system with a low-power TDC architecture (for example, as specified herein). Method 110 for measuring time intervals using one of the photodetector systems described above. An example of 0 is shown. Figure 11 shows an example of operation according to one embodiment, but in other embodiments, Figure 1 Any of the actions shown in 1 may be omitted, added, rearranged, and / or modified.

[0051] In operation 1102, TDC is initiated in response to the application of an optical pulse to the target. During the event detection time window, the photons of the light pulse are detected after the light pulse has been reflected from the target. A signal triggered by an event detected by the device, which enables the GRO of the TDC It receives a signal configured to be used. Operation 1102 is any of the methods described herein. This may be done.

[0052] In operation 1104, TDC uses GRO to determine when an event occurs and a predetermined event Measure the time interval between the end of the detection time window and the detection time. Operation 1104 is described herein. It may be performed using any of the following methods.

[0053] In operation 1106, the control circuit connected to TDC sets a time interval and a predetermined event Based on the detection time window, the arrival time of the photon to the photodetector is determined. Operation 1106 is performed This may be carried out in any of the manner described in the specification.

[0054] Figure 12 shows a specific configuration for performing one or more of the processes described herein. An example of a possible computer device 1200 is shown. As shown in Figure 12, the computer Device 1200 is connected to each other via the communication infrastructure 1210, enabling communication input Surface 1202, processor 1204, storage device 1206, and input / output ("I / O") ) Module 1208 may be provided. Figure 12 shows an example of computer device 1200. As shown, the components shown in Figure 12 are not intended to be limiting. Other actual components In the implementation, additional or alternative components may be used. That is also fine. Below, regarding the components of the computer device 1200 shown in Figure 12, Further details will be provided.

[0055] The communication interface 1202 communicates with one or more computer devices. It may be configured as follows. Examples of communication interface 1202 include, but are not limited to, ( Wired network interfaces (such as network interface cards), (wireless) Wireless network interfaces (such as network interface cards), modems Audio / video connections and any other suitable interfaces can be mentioned. ru.

[0056] The processor 1204 generally performs data processing and / or instructions as described herein. Interpretation, execution, and / or implementation of one or more processes and / or actions represents any type or format of processing device that can be instructed. Processor 1204 is a memory device Instructions 1212 (for example, apps) that can be executed by the computer are stored in location 1206. Applications, software, code, and / or other executable data instances The action may be performed by executing ).

[0057] The storage device 1206 comprises one or more data storage media, devices, or configurations. This may be used for any type, format, and combination of data storage media and / or devices. A suitable combination may be adopted. For example, the storage device 1206 may be any combination as described herein. This may include, but is not limited to, a non-volatile medium and / or a volatile medium. Electronic data, including the data described in the specification, may be stored temporarily and / or permanently in a storage device. It may be stored in 1206. For example, to perform any of the operations described herein. Instructions 1212 that can be executed by a computer configured to give instructions to processor 1204 The data representing may be stored in the storage device 1206. In some examples, the data The data may be placed in one or more databases located within the storage device 1206. .

[0058] The I / O module 1208 is configured to receive user input and provide user output. It may include one or more I / O modules. I / O module 1208 is , any hardware, firmware, software, or that supports input / output functions. Combinations of these may be included. For example, I / O module 1208 is not limited to However, keyboards, keypads, and touchscreen components (for example, touchscreens) Lean display), receiver (e.g., RF or infrared receiver), motion sensor , and / or one or more input buttons, including a mechanism for receiving user input. This may include hardware and / or software.

[0059] I / O module 1208 is a graphics engine, display (for example, D (Spray screen), one or more output drivers (e.g., display driver), 1 It comprises one or more audio speakers and one or more audio drivers, but Even if it includes one or more devices for presenting output to the user, it is not limited to Good. Depending on the embodiment, the I / O module 1208 may be a screen to present to the user. It is configured to provide graphical data. It can support multiple graphical user interfaces and / or specific implementations. It may represent any other graphical content.

[0060] In some examples, the systems, computer devices, and processes described herein The control unit and / or other components are all computer devices. It may be implemented by the 1200. For example, control circuit 106, signal processing circuit 110, The control circuit 216 may be implemented by the processor 1204.

[0061] In the above explanation, various exemplary embodiments have been described with reference to the attached drawings. Here it is. However, without departing from the scope of the present invention as described in the following claims Various modifications or changes can be made to this, or additional embodiments can be implemented. It will be clear that certain features of one embodiment described herein are the same as those described herein. Features of other embodiments described in this document may be combined with or substituted. Therefore, This description and the drawings should be understood as illustrative examples, not restrictive ones.

Claims

1. A head-mountable component configured to be worn on the user's head, comprising a head-mountable component including a photodetector, A time-to-digital converter (TDC) connected to the photodetector, During a predetermined event detection time window that begins in response to the application of an optical pulse to a target, a signal is received that is triggered by an event in which the photodetector detects the photons of the optical pulse after the optical pulse has been reflected from the target, and the signal is configured to enable the GRO of the TDC, which comprises one or more cross-connected inverters configured to store the state of the GRO when the GRO is disabled. A TDC is configured to use the GRO to measure a time interval between the occurrence of the event and the end of the predetermined event detection time window, which is measured by decoding the stored state of the GRO. A control circuit connected to the TDC, configured to determine the arrival time of the photon to the photodetector based on the time interval and the predetermined event detection time window. Equipped with, The TDC is configured to receive a voltage from a phase-locked loop (PLL) that supplies an external reference clock. A wearable system for use by the user, wherein at least one of enabling the GRO and measuring the time interval is performed based on the received voltage.

2. The aforementioned signal is While the aforementioned signal is being received by the TDC, the GRO of the TDC is enabled. The wearable system according to claim 1, further configured to disable the GRO of the TDC when the aforementioned signal stops.

3. The wearable system according to claim 1, wherein the TDC is further configured to receive a second signal configured to disable the GRO of the TDC after a predetermined event detection time window.

4. The wearable system according to claim 3, wherein the second signal is received when the predetermined event detection time window is completed.

5. The TDC is further configured to measure an additional time interval after the aforementioned time interval. The control circuit is further configured to calibrate the TDC based on the measured additional time interval, The wearable system according to claim 1, wherein the arrival time of the photon is determined based on further calibration of the TDC.

6. The wearable system according to claim 5, wherein the length of the additional time interval is the same as or substantially the same as the length of the predetermined event detection time window.

7. The wearable system according to claim 5, further comprising a calibration circuit configured to enable calculations for calibrating the TDC.

8. The wearable system according to claim 5, further comprising a lookup table configured to enable calculations for calibrating the TDC.

9. The wearable system according to claim 5, wherein the TDC is further configured to receive a second signal configured to disable the GRO of the TDC after the additional time interval.

10. The TDC is further configured to receive an event window signal that specifies the start time of the predetermined event detection time window. The wearable system according to claim 1, wherein the arrival time of the photon is determined based on the start time of the predetermined event detection time window.

11. The aforementioned photodetector is Single-photon avalanche diode (SPAD), A high-speed gate circuit configured to activate and deactivate the SPAD The wearable system according to claim 1, comprising:

12. The wearable system according to claim 1, wherein the head-mountable component is implemented by a non-invasive wearable brain interface system.

13. The wearable system according to claim 1, further comprising a wearable battery configured to supply power to the head-mountable component.

14. The wearable system according to claim 1, further comprising a processor configured to communicate with the control circuit.

15. The wearable system according to claim 14, further comprising a single housing configured to house the processor and the control circuit.

16. A first housing configured to house the control circuit, A second enclosure configured to house the aforementioned processor and The wearable system according to claim 14, further comprising the above.

17. The first housing comprises the head-mountable component, The wearable system according to claim 16, wherein the second housing is configured to be attached to a part of the user other than the head.

Images