165 results about "Electrode impedance" patented technology

A spinal cord stimulation (SCS) system includes multiple electrodes, multiple, independently programmable, stimulation channels within an implantable pulse generator (IPG) which channels can provide concurrent, but unique stimulation fields, permitting virtual electrodes to be realized. The SCS system includes a replenishable power source (e.g., rechargeable battery), that may be recharged using transcutaneous power transmissions between antenna coil pairs. An external charger unit, having its own rechargeable battery can be used to charge the IPG replenishable power source. A real-time clock can provide an auto-run schedule for daily stimulation. An included bi-directional telemetry link in the system informs the patient or clinician the status of the system, including the state of charge of the IPG battery. Other processing circuitry in the IPG allows electrode impedance measurements to be made. Further circuitry in the external battery charger can provide alignment detection for the coil pairs.

A spinal cord stimulation (SCS) system includes multiple electrodes, multiple, independently programmable, stimulation channels within an implantable pulse generator (IPG) which channels can provide concurrent, but unique stimulation fields, permitting virtual electrodes to be realized. The SCS system includes a replenishable power source (e.g., rechargeable battery), that may be recharged using transcutaneous power transmissions between antenna coil pairs. An external charger unit, having its own rechargeable battery can be used to charge the IPG replenishable power source. A real-time clock can provide an auto-run schedule for daily stimulation. An included bi-directional telemetry link in the system informs the patient or clinician the status of the system, including the state of charge of the IPG battery. Other processing circuitry in the IPG allows electrode impedance measurements to be made. Further circuitry in the external battery charger can provide alignment detection for the coil pairs.

The EEG Processing Unit comprises a semi-rigid framework which substantially conforms to the Patient's head and supports a set of electrodes in predetermined loci on the Patient's head to ensure proper electrode placement. The EEG Processing Unit includes automated connectivity determination apparatus which can use pressure-sensitive electrode placement ensuring proper contact with Patient's scalp and also automatically verifies electrode placement via measurements of electrode impedance through automated impedance checking. Voltages generated by the electrodes are amplified and filtered before being transmitted to an analysis platform, which can be a Physician's laptop computer system, either wirelessly or via a set of tethering wires. The EEG Processing Unit includes an automatic artifacting capability which identifies when there is sufficient clean data compiled in the testing session. This process automatically eliminates muscle- or other physical-artifact-related voltages. Clean data, which represents real brain voltages as opposed to muscle- or physical-artifact-related voltages, thereby are produced.

Disclosed are systems and methods which provide trial stimulators suited for use interoperatively and during patient trial. Trial stimulator embodiments provide a patient interface and / or clinician interface which appears and functions substantially the same as an interface of a pulse generator controller which will be used after a trial period. A compliance monitor feature may be provided to facilitate verifying the proper use of the trial stimulator during a trial period. A diagnostic feature may be provided to facilitate verifying proper operation of various aspects of a trial stimulator, such as electrode impedance analysis. Trial stimulators of embodiments provide stimulation to a plurality of tissues and / or areas of the body, such as spinal cord stimulation, deep brain stimulation, etcetera. Embodiments provide for multi-electrode stimulation and multi-stimulation programs. Embodiments are configured to provide active discharge of stimulation pulses as well as to utilize constant current sources in providing the stimulation pulses.

In one embodiment, the present invention includes a test signal generator capable of producing an impedance test signal comprising of a sine wave having a known frequency. The test signal generator may include a crystal oscillator, a counter, and a lookup table. The lookup table output is applied to a digital to analog converter and is then low pass filtered using a conventional analog filter to produce a sine wave of a known frequency and voltage amplitude. The test signal flows through the electrode and combines with an electrophysiological signal to form a combined signal. A signal processor is used to isolate the combined signal into the test signal component and the electrophysiological component. The signal processor digitally low pass filters the combined signal and the output of the low pass filter is the electrophysiological signal. The signal processor then digitally bandpass filters the combined signal using a filter with a center frequency which is the same as the test frequency. The output of this filter is then used to calculate the electrode impedance.

An implantable medical lead of the invention comprises an electrically active helix electrode extendable and retractable relative to a distal tip of the lead, an electrically conductive mapping collar disposed at the lead's distal tip and a proximal end carrying an electrical connector assembly. The electrical connector assembly comprises a first terminal connected to the helix electrode and a second terminal separately connected to the mapping collar. An advantage of the independent helix electrode and mapping collar circuits is that the implanting physician can confirm from separate electrode impedance readings that the helix is in fact extended and fully embedded within the myocardium. Further, the independent mapping collar and helix electrode circuits may be used, in conjunction with a configurable or programmable switch network, to provide the implanting physician with a choice of electrode impedances.

A method for fabricating an implantable medical electrode includes roughening the electrode substrate, applying an adhesion layer, and depositing a valve metal oxide coating over the adhesion layer under conditions optimized to minimize electrode impedance and post-pulse polarization. The electrode substrate may be a variety of electrode metals or alloys including titanium, platinum, platinum-iridium, or niobium. The adhesion layer may be formed of titanium or zirconium. The valve metal oxide coating is a ruthenium oxide coating sputtered onto the adhesion layer under controlled target power, sputtering pressure, and sputter gas ratio setting optimized to minimize electrode impedance and post-pulse polarization.

An slab CO2 laser includes spaced-apart elongated slab electrodes. A lasing gas fills a discharge gap between the electrodes. An RF power supply is connected across the electrodes and sustains an electrical discharge in the lasing gas in the discharge gap. Either one or two ceramic inserts occupy a portion of width of the electrodes and in contact with the electrodes. A discharge gap is formed between the portions of the width of the electrodes not occupied by the insert or inserts. Provision of the ceramic insert or inserts increases the resistance-capacitance (RC) time constant of the electrode impedance by increasing the capacitive component of the time constant. This hinders the formation of arcs in the discharge, which, in turn enables the inventive laser to operate with higher excitation power or higher lasing-gas pressure than would be possible without the dielectric insert. The ceramic insert also decreases the difference in impedance of the electrodes with and without a discharge. This leads to a better-behaved discharge, and a discharge that is easier to light.

A method and associated stimulation device for ensuring firing of an action potential in an intended physiological target activated by a stimulus pulse generated by an electrode of a non-invasive surface based stimulation device irrespective of skin-to-electrode impedance by: (i) increasing internal impedance of the stimulation device so as to widen a Chronaxie time period thereby ensuring firing of the action potential of the intended physiological target irrespective of the skin-to-electrode impedance; and / or (ii) generating a stimulation waveform that optimizes a non-zero average current (e.g., non-zero slope of the envelope of the stimulation waveform) during preferably substantially the entire current decay of the stimulus pulse.

The present invention relates to a system for measuring the impedance of a skin / electrode interface and selectively modifying the system gain of the monitoring circuit to compensate for errors introduced by variations in the skin / electrode impedance. More particularly, a simplified, low-cost method for measuring and compensating for skin / electrode impedance variations is provided. The skin / electrode impedance measuring circuit and determines a system gain correction factor which may be applied to the measured signal using a software algorithm, thereby eliminating the need to change the circuit topology with a programmable gain amplifier or programmable resistor network.

A critical element of a retinal prosthesis is the stimulating electrode array, which is placed in close proximity to the retina. It is via this interface that a retinal prosthesis electrically stimulates nerve cells to produce the perception of light. The impedance load seen by the current driver consists of the tissue resistance and the complex electrode impedance. The results show that the tissue resistance of the retina is significantly greater than that of the vitreous humor in the eye. Circuit models of the electrode-retina interface are used to parameterize the different contributors to the overall impedance.

The invention discloses a battery panel ground insulation impedance detection circuit which comprises a partial pressure subcircuit and a voltage detection unit (11), wherein the partial pressure subcircuit is used for connecting between a positive electrode (PV+) of a battery panel and a negative electrode (PV-) of the battery panel. The partial pressure subcircuit comprises a first resistor (R1), a fourth resistor (R4) and a second control switch, the first resistor (R1), the fourth resistor (R4) and the second control switch are connected in series, the second control switch enables a to-be-detected electrode to be connected or disconnected with planet earth (PE) through opening and closing states, and forms a plurality of various connection combinations according to connection between the to-be-detected electrode and the planet earth, and the voltage detection unit (11) is used for sequentially outputting a plurality of sampling voltages according to each various connection combination. The partial pressure subcircuit is formed by respectively connecting resistors on a positive electrode impedance and a negative electrode impedance, the various connection combinations are formed under the control of the second control switch, the plurality of sampling voltages are output, positive electrode ground insulation impedance and negative electrode ground insulation impedance can be calculated, and the problem that when one electrode of a battery is infinite in ground impedance, ground impedance of the other electrode of the battery can not be calculated.

Methods and apparatus for accurately and painlessly measuring the impedance between defibrillation electrodes implanted in a patient utilize a high current test pulse delivered with a sufficiently high current to produce an accurate measurement of the defibrillation electrode impedance while limiting the duration of the test pulse such that the pain sensing cells in the patient do not perceive the test pulse. In one embodiment, the test pulse is generated from the high voltage transformer without storing energy in the high voltage capacitors and is delivered to the defibrillation electrodes in the patient utilizing the high voltage switching circuitry.

The invention discloses a super-capacitor electrode material based on graded flowerlike NiCo2O4. The super-capacitor electrode material is graded flowerlike NiCo2O4 which is directly grown on the nickel mesh of a conductive substrate by a hydrothermal method. The flowerlike structure prepared by the method for preparing NiCo2O4 is formed by assembling nanometer sheets, and in-situ growth on the three-dimensional nickel mesh is realized by selecting experiment conditions; the preparation process is easy to operate and products are regular in shape; because the electrode material directly grows on the conductive substrate, thereby avoiding to add a conductive agent and a binding agent, greatly reducing electrode impedance, increasing the contact action between the graded structure electrode material and the conductive substrate, and increasing osmosis of electrolyte by loosely assembling the nanometer sheets.

The invention discloses a high-efficiency class-F and inverse class-F power amplifier. A transistor, a parasitic compensation circuit, a harmonic control circuit and an output fundamental wave impedance matching circuit are included. The harmonic control circuit is located between the parasitic compensation circuit and the output fundamental wave impedance matching circuit, and the parasitic compensation circuit is located between the transistor and the harmonic control circuit. As for a fixed work frequency, the input end of the harmonic control circuit forms a second harmonic short dot and a third harmonic open-circuit dot, the harmonic control circuit is composed of three micro-strips, and the parasitic compensation circuit is composed of an L-type micro-strip structure. A parasitic component compensation function can be achieved by adjusting electric length parameters of a micro-strip in the parasitic compensation circuit, and meanwhile drain electrode impedance conditions of the class-F and inverse class-F power amplifier can be achieved. By means of the class-F and inverse class-F power amplifier, influences of the parasitic component on the harmonic control circuit can be effectively reduced, precise control of second harmonics and the third harmonics is achieved, and work efficiency of the power amplifier is improved.

Methods and apparatus for accurately and painlessly measuring the impedance between defibrillation electrodes implanted in a patient utilize a high current test pulse delivered with a sufficiently high current to produce an accurate measurement of the defibrillation electrode impedance while limiting the duration of the test pulse such that the pain sensing cells in the patient do not perceive the test pulse. In one embodiment, the test pulse is generated from the high voltage transformer without storing energy in the high voltage capacitors and is delivered to the defibrillation electrodes in the patient utilizing the high voltage switching circuitry.

The present invention is intended to achieve measurement of electrode impedance that is not easily affected by fluid noise, and to accurately detect adhesion and discriminate the type of fluid. An electromagnetic flowmeter that is provided with a pipe through which the fluid to be measured is passed, applies a magnetic field to the above fluid driving the excitation coils using the excitation circuit, and thereby measures the flow rate of the fluid passing through the above-mentioned pipe; further comprising: a pair of detecting electrodes that detect the flow signal corresponding to the flow rate of the fluid passing through the above-described pipe, an earth electrode whose potential becomes the reference potential when the flow rate is measured, diagnosing signal generators that apply the diagnosing signals between the above detecting electrodes and the above earth electrode, and a diagnosis circuit to detect the resistance values between the above detecting electrodes and the above earth electrode as diagnostic signals.

A biomedical sensor system is disclosed that includes a high impedance conductive electrode having an electrode impedance of at least about 20 kΩ / sq-mil, and a dielectric material on a first side of the electrode for receiving a discharge of an electrical signal from the dielectric material responsive to the presence of a time varying signal adjacent a second side of the dielectric material that is opposite the first side.

The invention belongs to the field of battery manufacturing and particularly relates to an electrode coated with a conductive carbon layer on the surface. After the electrode is coated, the conductive carbon layer coats the surface of the electrode; and the variety of conductive carbon can be activated carbon, conductive carbon black, a carbon nano tube, graphene, mesoporous carbon, a carbon fiber and the like. The conductive carbon layer coats the surface of the battery electrode, so that the electrode impedance can be greatly reduced; an active material can be effectively protected; the stability of the electrode is improved; and the electrode is especially suitable for the field of application of a high-power battery.

Apparatuses and methods are provided for determining electrode impedances of a bioelectric signal-monitoring / recording system that includes an amplifier, and electrodes connected between a subject and the amplifier. An example apparatus includes: a voltage source outputting a voltage signal; a switching arrangement including an input electrically connected with the voltage source for receiving the voltage signal, an output electrically connected with the amplifier and the electrodes, and switches between the input and the output; and a controller in communication with the switches for opening and closing the switches to establish signal paths between the voltage source and the output, the controller calculating the electrode impedances relative to voltage outputs of the amplifier for each signal path.

The invention relates to a bioelectric electrode which is extensively applied to bioelectric recording, measurement and stimulation, including high-density electrode measurement, medical facilities, mobile equipments, family health care, psychological cognition, games, a brain-computer interface, rehabilitation training and the like, and is particularly applicable to electroencephalogram measurement. An electrode tip is a columnar pipe, and the middle part of the electrode tip is provided with an electrolyte circulating hole; one end of the electrode tip is a working end in contact with a living body, and the other end of the electrode tip is an electrolyte entering end; the electrode tip is located on one end plane of an electrode body; the middle part of the electrode body is provided with a cavity used for accommodating an electrolyte and communicating with a middle through hole; the electrode tip is a conductor, and the electrode body is either a conductor or an insulator; the electrode tip is communicated with an external circuit directly through the electrode body. The bioelectric electrode provided by the invention has the main advantages of being simple in structure, low and stable in electrode impedance, low in measurement noise, small in artifact, convenient and comfortable to use, and an electrolyte ion conductor and an electrode tip electronic conductor are simultaneously in contact with the skin, thereby being applicable to the relevant applications of bioelectricity recording, measuring and stimulation.

In one embodiment, the present invention includes a test signal generator capable of producing an impedance test signal comprising of a sine wave having a known frequency. The test signal generator may include a crystal oscillator, a counter, and a lookup table. The lookup table output is applied to a digital to analog converter and is then low pass filtered using a conventional analog filter to produce a sine wave of a known frequency and voltage amplitude. The test signal flows through the electrode and combines with an electrophysiological signal to form a combined signal. A signal processor is used to isolate the combined signal into the test signal component and the electrophysiological component. The signal processor digitally low pass filters the combined signal and the output of the low pass filter is the electrophysiological signal. The signal processor then digitally bandpass filters the combined signal using a filter with a center frequency which is the same as the test frequency. The output of this filter is then used to calculate the electrode impedance.

The invention relates to the fuel cell field, aims to provide a direct liquid fuel cell using conductive polymer modified carbon based cobaltous hydroxide composite catalyst. The cell comprises a negative pole using foam nickel as matrix and a positive pole using hydrophobic processed carbon paper or carbon cloth as matrix; The negative pole is made by mixing the conductive polymer modified carbon based cobaltous hydroxide composite catalyst, water, perfluoro sulfonic group resin solution with concentration of 5wt% and anhydrous ethanol, blending into slurry, coating on foam nickel and drying in air naturally. The beneficial effects of the invention is: conductive polymer can increase electrode electrical conductivity, reduce electrode impedance, improve electrode activity, and improve the electricity generation performance of cell; the synthesized conductive polymer modified carbon based cobaltous hydroxide composite catalyst is non-Pt catalyst, has a low cost, is favorable to the popularization of fuel cell technology.

The invention discloses an anti-overflow control system. An anti-overflow detecting support is arranged on a pot cover. When soup is boiled and bubbles overflow to a detecting electrode, the impedance of the anti-overflow electrode on the anti-overflow detecting support is changed, and the temperature of the environment in a pot is detected while the impedance is detected through a wireless radio frequency reader; meanwhile, temperature information and electrode impedance information are outputted to a cooking utensil control device to be judged, the cooking utensil control device then adjusts the heat power of a cooking utensil according to the judgment information so as to prevent soup from overflowing out of the pot, and then the anti-overflow effect is achieved.

The invention relates to a wearable bio-electricity signal collection device which is extensively applied to bioelectricity recording, measuring and stimulating, especially applicable to non-gel bio-electricity measurement. The collection device is formed by the connection of electrode support components; electrode support component comprises connecting belts and fixed pieces, wherein electrode mounting holes are formed in the middle of the fixed pieces, troughs for fixing the connecting belts are formed in the sides of the fixed pieces, and at least a pair of troughs in two are symmetrically formed in the two sides of each electrode mounting holes; the fixed pieces are fixed on one ends or two ends or middle parts of the connecting belt through the troughs in the fixed pieces, the connecting belts are elastic flat belts, and the fixed pieces are rigid flat blocks. The collection device provided by the invention has the advantages of being reasonable in structure, high in degree of fitness between the electrode support component and the skin, stable in electrode impedance, high in measurement precision, comfortable to wear, detachable in electrode, convenient to adjust the position and amount of electrodes, and the electrode is in well contact with the skin.

An exemplary method includes a sound processing unit 1) directing an implantable cochlear stimulator to apply a plurality of stimulation pulses each having a first pulse width by way of a plurality of electrodes during a first stimulation frame, the plurality of electrodes including a first electrode and a set of remaining electrodes, 2) detecting a change in impedance of the first electrode, 3) adjusting, in response to the change in impedance of the first electrode, a pulse width parameter associated with the first electrode to define a second pulse width, and 4) directing the implantable cochlear stimulator to apply a stimulation pulse having the second pulse width by way of the first electrode and a plurality of stimulation pulses having the first pulse width by way of the set of remaining electrodes during a second stimulation frame subsequent to the first stimulation frame.