# US 11,998,741 B2 · Charge compensation circuit for neural stimulation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,998,741 B2 - Document ID: US11998741B2 - Status: Granted - Kind: B2 - Application number: 17/445,214 - Filed: 2021-08-17 - Published: 2022-02-03 - Granted: 2024-06-04 - Earliest claimed: 2016-09-30 - Assignees: Shenzhen Sibionics Technology Co., Ltd. - Applicants: Shenzhen Sibionics Technology Co., Ltd. - Inventors: Bin Xia; Yu Zhao; Yu Lin; Zhi Chen - Web page: https://patentgrep.com/patent/US11998741B2 ## CPC - A61N 1/36046: {of the eye} - A61N 1/0543: {Retinal electrodes} - A61N 1/36125: {Details of circuitry or electric components} - A61N 1/36142: {for improving safety} - A61N 1/36175: {Pulse width or duty cycle} - H03K 3/017: Adjustment of width or dutycycle of pulses (pulse width modulation H03K7/08 {; to maintain energy constant H03K3/015}) - H03K 3/78: Generating a single train of pulses having a predetermined pattern, e.g. a predetermined number - H03K 5/00006: {Changing the frequency (modulating pulses H03K7/00; frequency dividers H03K21/00 - H03K29/00; additive or subtractive mixing of two pulse rates into one G06F7/605; pulse rate dividers G06F7/68)} - H03K 5/02: by amplifying (H03K5/04 takes precedence) - A61N 1/36157: {Current (A61N1/3616 takes precedence)} - A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B) - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) ## Abstract A pulse current generation circuit (100) for neural stimulation includes an analogue signal receiving device (101) for receiving an analogue signal; an analogue-to-digital converter (102) for converting the analogue signal into a digital control signal; a current signal controller (103) for producing, according to the digital control signal, pulse current parameters for generating bidirectional pulse current signals; and a current generator (104) for generating, according to the pulse current parameters, bidirectional pulse current signals for neural stimulation, and the current generator can generate pulse currents of different precisions according to the pulse current parameters. In addition, the present invention further relates to a charge compensation circuit, a charge compensation method, and an implantable electrical retina stimulator using the pulse current generation circuit or the charge compensation circuit. ## Claims ### Claim 1 A charge compensation circuit for neural stimulation, comprising: a detection circuit for detecting a total charge amount during one stimulation period of bidirectional pulse current signals generated by a current generator in a pulse current generation circuit; a judgment circuit for determining whether the total charge amount detected by the detection circuit exceeds a safe charge amount range; and a compensation circuit for generating a compensation pulse current signal with a net charge amount when the judgment circuit determines that the total charge amount exceeds the safe charge amount range, so that the total charge amount is within the safe charge amount range; wherein the charge compensation circuit is configured to determine whether to conduct charge compensation on the current generator according to the total charge amount during one stimulation period of the bidirectional pulse current signals generated by the current generator for neural stimulation to ensure that the total charge amount generated by the current generator is within the safe charge amount range. ### Claim 2 (depends on 1) The compensation circuit according to claim 1, wherein, when the judgment circuit judges that the total charge amount is a positive value, a compensation pulse current signal with a negative compensation charge amount is generated so that the total charge amount is within the safe charge amount. ### Claim 3 (depends on 1) The compensation circuit according to claim 1, wherein when the judgment circuit judges that the total charge amount is a negative value, a compensation pulse current signal with a positive compensation charge amount is generated so that the total charge amount is within the safe charge amount. ### Claim 4 (depends on 1) The compensation circuit according to claim 1, wherein: an amplitude of the compensation pulse current signal is lower than a preset amplitude; and a period of the compensation pulse current signal is less than a period of the bidirectional pulse current signals. ### Claim 5 (depends on 4) The compensation circuit according to claim 4, wherein the preset amplitude is a minimum current amplitude capable of playing a stimulation effect on a nerve tissue. ### Claim 6 (depends on 1) The compensation circuit according to claim 1, wherein a waveform of a positive pulse current signal is opposite to a waveform of a negative pulse current signal in the bidirectional pulse current signals. ### Claim 7 (depends on 1) The compensation circuit according to claim 1, wherein: the detection circuit is configured to detect a charge amount of a positive pulse current signal and an absolute value of a charge amount of a negative pulse current signal; and the judgment circuit is configured to compare the charge amount of the positive pulse current signal with the absolute value of the charge amount of the negative pulse current signal to judge whether the total charge amount exceeds the safe charge amount. ### Claim 8 (depends on 1) The compensation circuit according to claim 1, wherein: the judgment circuit is configured to judge whether an absolute value of an average value is greater than a preset value; and when the absolute value of the average value is greater than the preset value, the compensation circuit generates the compensation pulse current signal with the net charge amount, so that the total charge amount is within the safe charge amount. ### Claim 9 (depends on 1) The compensation circuit according to claim 1, wherein: the judgment circuit is configured to judge whether an absolute value of a voltage average value is greater than a preset voltage value; and when the absolute value of the voltage average value is greater than the preset voltage value, the compensation circuit generates the compensation pulse current signal with the net charge amount, so that the total charge amount is within the safe charge amount. ### Claim 10 (depends on 1) The compensation circuit according to claim 1, wherein the detection circuit is configured to detect an average value of the bidirectional pulse current signals generated by the current generator. ### Claim 11 (depends on 1) The compensation circuit according to claim 1, wherein: the detection circuit detects a current average value of the bidirectional pulse current signals generated by the current generator; and converts the current average value into a voltage average value. ### Claim 12 (depends on 11) The compensation circuit according to claim 11, wherein, when an absolute value of the voltage average value is greater than a preset voltage value and the voltage average value is a positive value, the compensation circuit generates the compensation pulse current signal with a negative net charge amount so that the total charge amount for neural stimulation is within the safe charge amount. ### Claim 13 (depends on 11) The compensation circuit according to claim 11, wherein, when the absolute value of the voltage average value is greater than a preset voltage value and the voltage average value is a negative value, the compensation circuit generates the compensation pulse current signal with a positive net charge amount so that the total charge amount for neural stimulation is within the safe charge amount. ### Claim 14 (depends on 1) The compensation circuit according to claim 1, wherein the compensation circuit adopts a charge compensation method by successive approximation. ### Claim 15 (depends on 14) The compensation circuit according to claim 14, wherein the charge compensation is conducted according to proportion values selected from a group consisting of 30%, 40%, 50%, 60%, 70%, and 80%. ### Claim 16 (depends on 1) The compensation circuit according to claim 1, wherein the detection circuit is always in a working state to detect in real time to conduct charge compensation when it detects that the charge amounts exceeds a standard. ### Claim 17 (depends on 1) The compensation circuit according to claim 1, wherein: the detection circuit comprises a first resistor, a second resistor and a capacitor; a negative pole of the capacitor and a first end of the first resistor are connected to a common voltage; a positive pole of the capacitor and a second end of the first resistor are connected to a second end of the second resistor; and a first end of the second resistor is connected to the pulse current generation circuit and the compensation circuit. ### Claim 18 (depends on 17) The compensation circuit according to claim 17, wherein: the judgment circuit comprises a first voltage comparator and a second voltage comparator; an in-phase input end of the first voltage comparator and an in-phase input end of the second voltage comparator are connected to the first end of the second resistor; a reverse-phase input end of the first voltage comparator is connected to a preset positive voltage, and a reverse-phase input end of the second voltage comparator is connected to a preset negative voltage; a power supply end of the first voltage comparator and a power supply end of the second comparator are connected to a power voltage; a grounding end of the first voltage comparator and a grounding end of the second comparator are connected to the common voltage; an output end of the first voltage comparator is connected to a first control end of the compensation circuit; and an output end of the second voltage comparator is connected to a second control end of the compensation circuit. ### Claim 19 (depends on 18) The compensation circuit according to claim 18, wherein: a power supply end of the compensation circuit is connected to the power voltage; a grounding end of the compensation circuit is connected to the common voltage; and an output end of the compensation circuit is connected to the input end of the pulse current generation circuit. ### Claim 20 (depends on 18) The compensation circuit according to claim 18, wherein: a power supply end of the pulse current generation circuit is connected to the power voltage; a grounding end of the pulse current generation circuit is connected to the common voltage; and an output end of the pulse current generation circuit is connected to an impedance load.