Hearing aid with ear EEG recording

Abstract

A hearing aid with ear EEG recording is disclosed, comprising: a plurality of electrode units, wherein each of the plurality of electrode units comprises an electrode configured to provide electrical stimulation to a hearing aid user and / or to measure a biological response signal of the user; a plurality of electrode channel circuits; wherein each of the plurality of electrode channel circuits comprises: an operational amplifier comprising a first input terminal configured to receive the biological response signal and to provide an amplified biological response signal, the operational amplifier comprising a first load input; a first DC offset unit configured to reduce the influence of a DC offset in said electrode channel circuit of the plurality of electrode channel circuits by receiving a portion of the amplified biological response signal and converting it into a feedback current signal, the feedback current signal being passed to the first load input thereby providing a balanced leakage current in the operational amplifier.

Description

Technical Field

[0001] This application relates to a hearing aid having an electrode unit for recording biological response signals such as electroencephalography (EEG) signals of a hearing aid user, the hearing aid including an improved EEG topology. Background Technology

[0002] Biological response signals are understood here as potential differences originating from living organisms. Well-known examples are electrocardiogram (ECG) and electroencephalogram (EEG) signals. Ear devices used to detect biological response signals in the ear are typically manufactured for EEG signal detection, but can also be used to detect other bioelectrical signals such as ECG, electrooculography (EOG), or muscle activity.

[0003] EEG signals are electrical signals generated by human brain activity. In recent years, EEG monitoring systems have been designed that can be continuously carried or worn by the person being monitored. The goal is to have a personal wearable EEG monitor that can be carried without causing more inconvenience than glasses or modern small hearing aids.

[0004] Such EEG monitors can be applied to various purposes. One example is the monitoring of a person's condition, such as providing alerts or information when predetermined conditions are met. The monitor can also be used for data collection, for example, for diagnostic purposes or research. Examples of applications include monitoring people with diabetes or epilepsy. Another example is its use as an input for controlling or adjusting hearing aids.

[0005] Furthermore, the potentials of neural activity originating from cranial nerves and the brainstem can also be measured using hearing aids. This is suitable, for example, in assessing hearing loss, where it is common to measure responses from cranial nerves (cranial nerve 8) and responses from the brainstem (auditory brainstem response). However, it is also suitable to measure responses from, for example, the vagus nerve which branches in the outer ear, or stimulation of the vagus nerve (cranial nerve 10). This is suitable, for example, in epilepsy.

[0006] Compared to surrounding interference, the amplitude of electrophysiological signals, or biological response signals, is typically weaker. For example, biological response signals such as electroencephalogram (EEG) signals measured by non-invasive electrodes range from 10 μV to 100 μV, and electrocardiogram (ECG) signals measured by non-invasive electrodes range from 100 μV to 1 mV, while coupling interference from the surrounding environment can easily reach the millivolt or even volt levels. Most of these interferences usually occur alongside biological response signals in a common manner. Therefore, interference immunity is crucial for recording biological response signals. In traditional solutions that provide improved interference immunity, the electrode offset voltage (EOV) is compensated at the amplifier input. The digital-to-analog converter (DAC) is typically connected to the amplifier input, and the amplifier imposes fairly stringent requirements on the DAC's reference, particularly the power supply rejection ratio (PSRR) and / or common mode rejection ratio (CMRR). Furthermore, DACs always introduce transient spikes that will appear at the amplifier's input and cause harmonic distortion at the operational amplifier's output. The amplifier can be a chopper amplifier configured to reduce flicker noise in the operational amplifier.

[0007] The CMRR of an operational amplifier is the suppression of unwanted input signals from both input terminals relative to the desired difference signal.

[0008] The PSRR of an operational amplifier is the ratio of the change in supply voltage to the equivalent (differential) output voltage it produces.

[0009] Furthermore, the half-cell potential and resistance of electrodes used to record biological response signals and / or stimuli vary significantly. For example, the half-cell potential varies from at least -300 mV to +300 mV, and the resistance varies from 20 kΩ to 10 MΩ or even higher. Therefore, achieving good CMRR and / or PSRR under these conditions is very challenging.

[0010] Therefore, it is important to improve noise or interference immunity and increase the tolerance of recording electrode variations when recording biological response signals. Summary of the Invention

[0011] One aspect of the present invention is to provide a hearing aid that improves bio-response recording performance by minimizing DC offset voltage and enhancing PSRR and reducing CMRR.

[0012] According to the first aspect, the hearing aid includes a plurality of electrode units, each of which includes an electrode configured to provide electrical stimulation to a hearing aid user and / or measure the user's biological response signals.

[0013] One of the multiple electrode units may include an active electrode for recording biological reactions, particularly for advanced electrode technologies such as contactless and dry contact electrodes. The purpose of using an active electrode is to shield the electrode from external interference and compensate for parasitic capacitance.

[0014] Compared to passive electrodes, active electrodes typically offer better immunity to environmental interference and capacitive coupling interference such as power line interference (PLI). Therefore, they are well-suited for emerging applications in wearable bio-reaction recording. Active electrodes can be combined with right leg-driven technology. Generally, active electrodes offer several advantages, including sufficiently low involved input noise, high input impedance and low bias current, low involved input offset, low output impedance, high common-mode rejection ratio (CMRR) and power supply rejection ratio (PSRR), and, for hearing aid devices, low power consumption.

[0015] In addition, the hearing aid may include multiple electrode channel circuits, each of which includes an operational amplifier having a first input terminal configured to receive and provide an amplified bio-response signal; and a first DC offset unit configured to reduce the DC offset in the electrode channel circuits by receiving a portion of the amplified bio-response signal and converting it into a feedback current signal, the feedback current signal being transmitted to a first load input or a first input terminal of the operational amplifier to provide balanced leakage current in the operational amplifier.

[0016] Each of the multiple electrode channel circuits can be a differential circuit, meaning that two electrode units (parts of the multiple electrode units) are connected to a single electrode channel circuit in the multiple electrode channel circuits. One of the two electrode units can be a common electrode of at least two of the multiple electrode channel circuits, and the common electrode unit can be used as a reference electrode in both electrode channel circuits.

[0017] Each of the multiple electrode units can be connected to one of the multiple electrode channel circuits, thereby improving the quality of the biological response signal or applying stimulation to the user via the electrode unit.

[0018] An operational amplifier can be a differential amplifier, where the first input terminal is a differential input terminal.

[0019] The operational amplifier may have a second load input configured to receive a reference voltage. The second load input may be a positive power supply port, and the first load input may be a negative power supply port.

[0020] The first input terminal of an operational amplifier can be either an inverting or non-inverting port.

[0021] An operational amplifier includes leakage current, which includes a first leakage current and a second leakage current. When the first and second leakage currents are equal or approximately equal, the operational amplifier includes balanced leakage current.

[0022] The input of the first DC offset unit can be connected to the output of the operational amplifier, and the output of the first DC offset unit can be connected to the first load input. The first DC offset unit can be configured to reduce the DC offset that may be applied to the amplified bio-response signal. The reduced DC offset voltage results in a significant reduction in the PSRR requirement of the operational amplifier's reference voltage. Furthermore, since the output of the first DC offset unit is isolated and connected to the first load input, transient spikes in the amplified bio-response signal are also eliminated.

[0023] Each of the plurality of electrode channel circuits may include a second DC offset unit configured to receive a biological response signal, reduce DC offset, and forward the DC offset-reduced biological response signal to an operational amplifier. The input of the second DC offset unit may be connected to one of the plurality of electrode units, and the input may be configured to receive the biological response signal recorded by that electrode unit. The second DC offset unit may be connected to a first input terminal of the operational amplifier. The second DC offset unit is configured to partially eliminate the DC offset voltage at the input of the operational amplifier, thereby enhancing PSRR. It is also combined with the first DC offset unit to provide a further improved reduction of the DC offset voltage at minimal cost to the signal strength of the biological response signal.

[0024] The hearing aid may include an analog-to-digital converter (ADC) through which amplified bio-reactive signals can be converted into digital electrical signals; and a first DC offset unit may include offset correction circuitry configured to receive the digital electrical signals and provide a digital offset correction signal based on a measurement of a DC offset voltage in the digital electrical signals. The first DC offset unit includes a first digital-to-analog converter (DAC) configured to receive the digital offset correction signal and convert it into a feedback current signal that can be passed to a first load input of an operational amplifier.

[0025] The first DC offset unit may include a second digital-to-analog converter configured to receive a digital offset correction signal and convert it into another feedback current signal that can be transmitted to a second input of an operational amplifier or to a first input terminal of an operational amplifier and combined with a biological response signal.

[0026] Combining a first digital-to-analog converter (DAC) and a second DAC that provide feedback current signals to the first load input and the first input terminal of the operational amplifier, respectively, offers advantages over the case with only one feedback current signal. The requirements for the operational amplifier's reference voltage and PSRR for transient spike signals are significantly reduced because only a portion of the DC offset voltage is compensated at the operational amplifier's input. CMRR performance is also improved.

[0027] In another example, the first DC offset unit may include a controller configured to provide control signals based on digital electrical signals, an offset energy storage capacitor connected to a first input terminal or a first load input of the operational amplifier, and a pulsed current source configured to increase or decrease the voltage level of the offset energy storage capacitor at discrete steps based on the control signals, wherein the offset energy storage capacitor is configured to maintain the voltage level at a level proportional to the DC offset voltage at the first input terminal or the first load input, thereby providing balanced leakage current for the operational amplifier.

[0028] By replacing the DAC with an offset energy storage capacitor, the noise problems and power consumption of the digital-to-analog converter (DAC) are avoided.

[0029] The controller can be configured to determine the distance by varying the magnitude and / or duration of the current pulses provided by the pulsed current source. This allows the duty cycle of the pulsed current source to be controlled, resulting in a very small duty cycle and minimizing power consumption. Typically, DACs are driven with a 100% duty cycle, leading to significantly higher power consumption than when using a pulsed current source.

[0030] In another example, the first DC offset unit may include a first digital-to-analog converter (DAC), an offset energy storage capacitor, a controller, and a pulse current source, thereby avoiding a second DAC and obtaining similar advantages as when using both the first and second DACs. Consequently, additional advantages are gained, such as avoiding the additional noise provided by the second DAC and avoiding the power consumption of the second DAC.

[0031] The pulsed current source can be turned on and off based on input from the controller, wherein the pulsed current source is turned on when the controller detects a DC offset or a DC offset above a DC offset threshold; and wherein the pulsed current source is turned off when the controller does not detect a DC offset or detects a DC offset below the DC offset threshold. Thus, the pulsed current source is used only when needed, and when combined with a small duty cycle, the power consumption of the pulsed current source is further reduced compared to the case with only a small duty cycle.

[0032] The second DC offset unit may include a shunt impedance circuit comprising a plurality of shunt resistors and a voltmeter configured to measure the output voltage at the output of the second DC offset unit, wherein the impedance matching unit may be configured to match a first impedance to at least a second impedance based on a first measured output voltage of a primary second DC offset unit connected to the first electrode unit and a second measured output voltage of a secondary second DC offset unit connected to the second electrode unit.

[0033] If the DC offset voltage (or electrode offset voltage) becomes too large, resulting in poor CMRR, the operational amplifier may apply a bias at different DC operating points. However, this is mitigated by applying impedance matching units to each of the multiple electrode channel circuits.

[0034] Each of the plurality of electrode channel circuits may include an impedance matching unit configured to receive a biological response signal and to match a first impedance of a first electrode unit among the plurality of electrode units to at least a second impedance of a second electrode unit among the plurality of electrode units. The input of the impedance matching unit may be connected to an electrode unit among the plurality of electrode units configured to receive a biological response signal, and the output of the impedance matching unit may be connected to a first input terminal of an operational amplifier or an input of a second DC offset unit.

[0035] The impedance matching unit can be configured to receive the biological response signal and forward the impedance-matched biological response signal to the operational amplifier or the second DC offset unit.

[0036] By combining the impedance matching unit and the first DC offset unit, recording performance will be improved because the CMRR is increased while the offset voltage is reduced or minimized.

[0037] The hearing aid may include a stimulator unit configured to apply alternating current, direct current, or a combination thereof to at least one of a plurality of electrode units, wherein the at least one electrode unit may be configured to apply electrical stimulation based on current.

[0038] By applying alternating current through a first electrode unit and recording one or more biological response signals through a second electrode unit, it is possible to determine resistive and reactive impedances, such as capacitive and / or inductive reactance. By potentially determining both impedances, a more reliable method of impedance determination is provided, thereby improving CMRR performance.

[0039] The stimulator unit can be configured to transmit alternating current, direct current, or a combination thereof to a first impedance matching unit of a first electrode channel circuit in a plurality of electrode channel circuits, wherein the first impedance matching unit can be configured to forward current to a first electrode unit in a plurality of electrode units.

[0040] The second impedance matching unit of the second electrode channel circuit in the multiple electrode channel circuit can be configured to measure multiple impedances of the second electrode unit in the multiple electrode units, and determine the resistive impedance and / or reactive impedance of the second electrode unit in the multiple electrode units based on the multiple measured impedances.

[0041] A hearing aid can be configured to compensate for the hearing loss of a hearing aid user, comprising: a microphone configured to receive sound waves and provide an audio signal based on the sound waves; a signal processor unit configured to process the audio signal and provide the processed audio signal; and an output converter configured to output the processed audio signal to the user; wherein the signal processor unit can be configured to process the audio signal based on amplified bio-response signals, or can be configured to adjust a hearing profile stored in the hearing aid's memory based on amplified bio-response signals.

[0042] The hearing aid may include an in-ear unit, a post-auricular unit, a communication link configured to provide an electrical connection between the in-ear unit and the post-auricular unit, and a processor unit configured to receive amplified bio-response signals via the communication link, wherein one or more of a plurality of electrode units are disposed in the in-ear unit and the processor unit is disposed in the post-auricular unit of the hearing aid.

[0043] Multiple electrode channel circuits can be set in the in-ear unit and / or the post-ear unit.

[0044] The communication link can be a communication bus or a wireless communication link.

[0045] Hearing aids may include a housing comprising multiple electrode units and multiple electrode channel circuits. The housing may be an in-ear hearing aid.

[0046] The first DC offset voltage unit can be referred to as the DC servo loop. Attached Figure Description

[0047] Various aspects of the invention will be best understood from the following detailed description taken in conjunction with the accompanying drawings. For clarity, these drawings are schematic and simplified, showing only the details necessary for understanding the invention while omitting other details. Throughout the specification, the same reference numerals are used for the same or corresponding parts. Features of each aspect may be combined with any or all features of other aspects. These and other aspects, features, and / or technical effects will be apparent from and illustrated in the following figures, wherein:

[0048] Figures 1A-1B An example of an electrode channel circuit is shown;

[0049] Figure 2 An example of a circuit with multiple electrode channels is shown;

[0050] Figures 3A-3B Another example of an electrode channel circuit is shown;

[0051] Figure 4 An example of determining electrode impedance is shown;

[0052] Figures 5A-5BAn example of a circuit with multiple electrode channels is shown;

[0053] Figures 6A-6B An example of an electrode channel circuit is shown;

[0054] Figures 7A-7D An example of an electrode channel circuit is shown; and

[0055] Figures 8A-8B An example of a hearing aid is shown. Detailed Implementation

[0056] The detailed description below, taken in conjunction with the accompanying drawings, serves as a description of various different configurations. This detailed description includes specific details to provide a thorough understanding of several different concepts. However, it will be apparent to those skilled in the art that these concepts can be implemented without these specific details. Several aspects of the hearing aid are described by various different blocks, functional units, modules, elements, circuits, steps, processes, algorithms, etc. (collectively, "elements"). Depending on the specific application, design constraints, or other reasons, these elements may be implemented using electronic hardware, computer programs, or any combination thereof.

[0057] Electronic hardware may include microelectromechanical systems (MEMS), (e.g., application-specific integrated circuits), microprocessors, microcontrollers, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), gating logic, discrete hardware circuits, printed circuit boards (PCBs) (e.g., flexible PCBs), and other suitable hardware configured to perform the various functions described in this specification, such as sensors for sensing and / or recording the physical properties of the environment, devices, users, etc. Computer programs should be interpreted broadly as instructions, instruction sets, code, code segments, program code, programs, subroutines, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, programs, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description languages, or other names.

[0058] Hearing aids are designed to improve or enhance a user's hearing ability by receiving sound signals from the user's environment, generating corresponding audio signals, possibly modifying those audio signals, and providing the possibly modified audio signals as audible signals to at least one of the user's ears. "Improving or enhancing a user's hearing ability" may include compensating for an individual user's specific hearing loss. "Hearing instrument" may also refer to a device suitable for electronically receiving audio signals, possibly modifying those audio signals, and providing the possibly modified audio signals as audible signals to at least one of the user's ears, such as wearable devices, headsets, or headphones. The audible signal may be provided in the following forms: acoustic signals radiated into the user's outer ear; sound signals transmitted as mechanical vibrations through the bone structures of the user's head and / or through parts of the middle ear to the user's inner ear; and electrical signals transmitted directly or indirectly to the user's cochlear nerve and / or auditory cortex. Hearing instruments are suitable for wearing in any known manner. This may include: i) placing the unit of the hearing device behind the ear (having a tube to guide acoustic signals into the ear canal or having a receiver / speaker positioned close to or within the ear canal and connected via a wire (or wirelessly) to the unit behind the ear), such as a behind-the-ear hearing aid; and / or ii) placing the hearing device wholly or partially within the user's auricle and / or ear canal, such as an in-the-ear hearing aid or a canal / deep-in-the-canal hearing aid; or iii) positioning the unit of the hearing device to be connected to a fixation device implanted into the skull, such as a bone-anchored hearing aid or a cochlear implant; or iv) positioning the hearing device unit as a wholly or partially implanted unit, such as a bone-anchored hearing aid or a cochlear implant. The hearing device may be implemented in a single unit (housing) or in multiple units interconnected with each other.

[0059] Hearing aid 1 includes multiple electrode units, each of which includes an electrode configured to provide electrical stimulation to a hearing aid user and / or measure the user's biological response signal BS. The hearing aid includes multiple electrode channel circuits, each of which is connected to one or more electrode units. Reference is now made to... Figure 1A and 1B The diagram illustrates electrode channel circuit 10 among multiple electrode channel circuits. Electrode channel circuit 10 includes an operational amplifier 4, which includes a first input terminal 5A configured to receive a biological response signal BS and provide an amplified biological response signal ABS. Operational amplifier 4 may be a differential operational amplifier, where the first input terminal is a differential input terminal, and the biological response signal BS represents a differential signal. Electrode channel circuit 10 may be connected to at least two of multiple electrode units. For example, electrode channel circuit 10 may be connected to a first electrode unit and a second electrode unit, where the second electrode unit is a common electrode unit for at least two of the multiple electrode channel circuits. The user's biological response signal may be a combination of the inputs from the two electrode units. Figure 1AIn the electrode channel circuit 10, a first DC offset unit 8 is configured to reduce the effect of DC offset in the electrode channel circuit 10 by receiving the digital portion 7 of the amplified bioreaction signal ABS and converting it into a feedback current signal FCS that provides balanced leakage current in the operational amplifier 4, thereby passing it to the first load input 6. Figure 1B In this configuration, the first DC offset unit 8 is configured to provide another feedback current signal FCS2, which is transmitted to the first input terminal 5A of the operational amplifier 4 and combined with the biological response signal BS.

[0060] In the remaining illustrations of electrode channel circuit 10, electrode channel circuit 10 includes a programmable gain amplifier (PGA) for providing programmable gain to the amplified biological response signal. A PGA is not required.

[0061] Figure 2 An example of multiple electrode channel circuits, including a first electrode channel circuit 10A and a second electrode channel circuit 10B, combined via a digital control unit or digital filter, is shown. In this example, the outputs of the two channels (10A, 10B) are combined via a digital control unit 20. The first electrode channel circuit 10A is connected to a first electrode unit and a second electrode unit among multiple electrode units, and the second electrode channel circuit 10B is connected to a second electrode unit and a third electrode unit, wherein the second electrode unit serves as a common electrode unit for both electrode channel circuits (10A, 10B). The first electrode channel circuit 10A receives a biological response signal BS from a first electrode E1 and a common electrode E2 and provides an electrode voltage input (EA(Vin)) and an offset electrode voltage (EA(EOV)). Similarly, the second electrode channel circuit 10B receives a biological response signal BS from a third electrode E3 and a common electrode E2 and provides an electrode voltage input (EB(Vin)) and an offset electrode voltage (EB(EOV)).

[0062] Figure 3A and 3B Another example of the electrode channel circuit 10 is shown. In these examples, the first DC offset unit 8 and Figure 1A Similar to what is shown, however, as an alternative, one can also use Figure 1B The first DC offset unit 8 is shown in the diagram. Figure 3A In the electrode channel circuit 10, a second DC offset unit 14 is included, configured to receive the biological response signal BS and reduce the DC offset in the electrode channel circuit. The biological response signal with reduced DC offset is forwarded to the operational amplifier 4. Figure 3BIn this embodiment, the electrode channel circuit 10 includes an impedance matching unit 16 configured to receive a biological response signal BS and to match a first impedance of a first electrode unit E1 among a plurality of electrode units E to at least a second impedance of a second electrode unit E2 among a plurality of electrode units E. In this example, the impedance matching unit 16 is configured to measure an output voltage of the impedance matching unit 16, and based on this output voltage, the impedance matching unit 16 is configured to adjust the impedance of the first electrode E1.

[0063] The hearing aid 1 includes a stimulator unit configured to transmit alternating current, direct current, or a combination thereof via electrode channel circuits 10 of a plurality of electrode channel circuits to at least one electrode unit (E) of a plurality of electrode units, wherein the at least one electrode unit (E) is configured to apply current-based electrical stimulation to a user. In one example, the stimulator unit may be configured to distribute current to each of the plurality of electrode channel circuits 10, each of the plurality of electrode channel circuits 10 being configured to forward the current to one or more electrode units (E). In another example, the stimulator unit may be disposed in each of the plurality of electrode channel circuits 10. Figure 4 An example is shown where the second electrode unit E2 is configured to apply stimulation provided by the stimulator unit via the second electrode channel circuit 10B, based on alternating current, direct current, or a combination thereof. Current can flow from the stimulator unit to the second electrode unit E2 via the impedance matching unit 16A of the second electrode channel circuit 10B. The first electrode unit E1 receives a biological response signal BS and forwards it to the first electrode channel circuit 10A. The biological response signal BS passes through the impedance matching unit 16 of the first electrode channel circuit 10A. The impedance matching unit 16 of the first electrode channel circuit 10A is configured to measure the output voltage of the unit 16, based on which resistive impedance and / or reactive impedance can be determined.

[0064] Figure 5A and 5B An example of two electrode channel circuits (10A, 10B) connected via a digital control unit 20 is shown. In this example, both circuits (10A, 10B) include an impedance matching unit 16. Figure 5A The diagram shows an example of how the impedance determination of the corresponding impedance matching unit 16 is performed within the corresponding impedance matching unit 16. Figure 5B An example is shown where the impedance of the corresponding impedance matching unit 16 is determined by the impedance processor unit 22.

[0065] In other examples, the two-channel (10A, 10B) DAC 7 can be removed and replaced with a single DAC located at the output of the combiner unit 20.

[0066] Impedance processor unit 22 can be connected to each impedance matching unit 16 in multiple electrode channel circuits (10A, 10B).

[0067] Figure 6A and 6B An example of an electrode channel circuit 10, including at least an impedance matching unit 16 and a second DC offset unit 14, is shown. The electrode channel circuit 10 receives the bioreaction signal BS via the impedance matching unit 16 and forwards the impedance-matched bioreaction signal to the second DC offset unit 14. The second DC offset unit 14 reduces the DC offset voltage that may appear in the bioreaction signal BS and transmits the DC offset voltage-reduced bioreaction signal to the operational amplifier 4. A first DC offset unit 8 receives a portion of the amplified bioreaction signal from the operational amplifier 4 and provides a feedback current signal to the operational amplifier 4 to balance the leakage current in the operational amplifier. The balanced leakage current causes a further reduction in the DC offset voltage in the amplified bioreaction signal ABS. The first DC offset unit 8 differs in both figures.

[0068] Figures 7A-7D Different examples of the first DC offset voltage unit 8 in a configured electrode channel circuit 10 are shown. Similar examples of the first DC offset voltage unit 8 may appear in electrode channel circuits 10 with different configurations. Figure 7A In this circuit, the first DC offset voltage unit 8 includes an offset correction circuit 24 configured to receive the amplified bioreaction signal ABS, which is converted into a digital electrical signal by an analog-to-digital converter 7. The offset correction circuit 24 is configured to integrate the digital electrical signal and provide a digital offset correction signal based on the integral, which is equal to the undesirable DC offset voltage in the amplified bioreaction signal ABS. The digital offset correction signal is then converted into a feedback current signal FCS by a first digital-to-analog converter 26 and transmitted to the first load input 6 of the operational amplifier 4.

[0069] Figure 7B Another example of the first DC offset voltage unit 8 is shown. In this example, the first DC offset voltage unit 8 is... Figure 7A Similar to that described elsewhere, but the first DC offset voltage unit 8 includes a second digital-to-analog converter 28 configured to receive a digital offset correction signal and convert it into another feedback current signal FCS2, which is then fed to the first input terminal of the operational amplifier in combination with the bioreaction signal. The second digital-to-analog converter receives the digital offset correction signal from the offset correction circuit 24 and provides the other feedback current signal FCS2 to the first input terminal. Thus, the DC offset voltage in the bioreaction signal is compensated before and within the operational amplifier 4, resulting in a more reliable amplified bioreaction signal than in the prior art.

[0070] Figure 7CAnother example of the first DC offset unit 8 is shown. In this example, unit 8 includes a controller 34 configured to provide control signals based on digital electrical signals provided by ADC 7. Unit 8 includes an offset energy storage capacitor 30 connected to the first load input 6 of operational amplifier 4 (or alternatively, connected to the first input terminal 5A). Unit 8 includes a pulsed current source 32 configured to increase or decrease the voltage level of the offset energy storage capacitor 30 by an offset length based on the control signals. The offset energy storage capacitor 30 is configured to maintain a voltage level proportional to the DC offset voltage at the first input terminal 5A or the first load input 6, thereby providing balanced leakage current for operational amplifier 4. The controller 34 is configured to determine the offset length by varying the magnitude and / or duration of the current pulses provided by the pulsed current source 32.

[0071] Figure 7D Another example of the first DC offset unit 8 is shown, which is related to Figure 7B The first DC offset unit shown is similar, except that the first digital-to-analog converter 26 is replaced by a controller 34, an offset energy storage capacitor 30, and a pulse current source 32.

[0072] Figure 8A and 8B Different examples of hearing aid 1, including multiple electrode channel circuitry, are shown. Figure 8A In this design, at least two (E1, E2) of a plurality of electrode units are disposed on an earpiece connected to a behind-the-ear (BTE) hearing aid. The connection between the BTE and the earpiece is provided by an I3C wire. In one communication mode, the I3C wire is configured to communicate between the plurality of electrode units and a plurality of electrode channel circuits that may be disposed in the BTE. In a second communication mode, the I3C wire transmits electrical signals and / or data unrelated to the communication of biological response signals. Figure 8B In the above, hearing aid 1 is an in-ear hearing aid, in which the electrodes are set on the shell of hearing aid 1.

[0073] Unless explicitly stated otherwise, the singular forms “a” and “the” used herein include the plural forms (i.e., meaning “at least one”). It should be further understood that the terms “having,” “comprising,” and / or “including” as used in the specification indicate the presence of the stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof. It should be understood that, unless explicitly stated otherwise, when an element is referred to as “connected” or “coupled” to another element, it may be a direct connection or coupling to the other element, or there may be intermediate inserting elements. The term “and / or” as used herein includes any and all combinations of one or more of the listed related items. Unless explicitly stated otherwise, the steps of any method disclosed herein do not necessarily have to be performed in the exact order disclosed.

[0074] It should be understood that references to "an embodiment," "an embodiment," "an aspect," or "may" in this specification mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the invention. Furthermore, particular features, structures, or characteristics may be suitably combined in one or more embodiments of the invention. The foregoing description is provided to enable those skilled in the art to implement the various aspects described herein. Various modifications will be apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Unless expressly stated, elements referred to in the singular do not mean "one and only one," but rather "one or more." Unless expressly stated, the term "some" means one or more.

[0075] Therefore, the scope of this invention should be determined based on the claims.

Claims

1. A hearing aid, comprising: - Multiple electrode units, each of which includes electrodes configured to provide electrical stimulation to a hearing aid user and / or measure the user's biological response signals; - Multiple electrode channel circuits, wherein each of the multiple electrode channel circuits includes -- An operational amplifier including a first input terminal, configured to receive and provide amplified biological response signals; -- A first DC offset unit configured to reduce the effect of DC offset in multiple electrode channel circuits by receiving a portion of an amplified biological response signal and converting it into a feedback current signal, the feedback current signal being passed to the first load input to provide balanced leakage current in the operational amplifier; The hearing aid further includes an analog-to-digital converter, wherein the amplified bio-reaction signal is converted into a digital electrical signal by the analog-to-digital converter, and the first DC offset unit includes: - A controller configured to provide control signals based on digital electrical signals; - An offset energy storage capacitor connected to the first input terminal of the operational amplifier or connected to the first load input; - A pulsed current source configured to increase or decrease the voltage level of the offset energy storage capacitor based on a control signal with an offset step length; The offset energy storage capacitor is configured to maintain the voltage level at a level proportional to the DC offset voltage at the first input terminal or the first load input, thereby providing balanced leakage current for the operational amplifier.

2. The hearing aid according to claim 1, wherein, Each of the multiple electrode channel circuits includes a second DC offset unit configured to receive biological response signals, reduce the effects of DC offset, and forward biological response signals.

3. The hearing aid according to claim 2, wherein, Each of the plurality of electrode channel circuits includes an impedance matching unit configured to receive a biological response signal and to match a first impedance of a first electrode unit in the plurality of electrode units to at least a second impedance of a second electrode unit in the plurality of electrode units.

4. The hearing aid according to claim 3, wherein, The impedance matching unit is configured to receive the biological response signal and forward the impedance-matched biological response signal to the operational amplifier or the second DC offset unit.

5. The hearing aid of claim 3, comprising a stimulator unit configured to apply alternating current, direct current, or a combination thereof to at least one of a plurality of electrode units via an impedance matching unit of one of a plurality of electrode channel circuits, wherein the at least one electrode unit is configured to apply electrical stimulation based on current.

6. The hearing aid according to claim 5, wherein, The second impedance matching unit of the second electrode channel circuit in the multiple electrode channel circuit is configured to measure multiple impedances of the second electrode unit in the multiple electrode units, and based on the multiple measured impedances, determine the resistive impedance and / or capacitive reactance of the second electrode unit in the multiple electrode units in the second impedance matching unit or in the impedance processor unit of the hearing aid.

7. The hearing aid according to claim 1, wherein, The controller is configured to determine the distance step by changing the magnitude and / or duration of the current pulse provided by the pulse current source.

8. The hearing aid according to claim 1, wherein, The pulsed current source is turned on and off based on input from the controller, wherein the pulsed current source is turned on when the controller detects a DC offset or a DC offset higher than a DC offset threshold; The pulse current source is turned off when the controller does not detect DC offset or detects a DC offset below the DC offset threshold.

9. The hearing aid according to claim 1, wherein, Hearing aids are configured to compensate for the hearing loss of the hearing aid user and include: - A microphone configured to receive sound waves and provide audio signals based on the sound waves; - A signal processor unit configured to process audio signals and provide processed audio signals; - Configured to output the processed audio signal to the user's output converter; The signal processor unit is configured to process audio signals based on amplified bio-response signals, or to adjust hearing profiles stored in the hearing aid's memory based on amplified bio-response signals.

10. The hearing aid according to claim 1, comprising: - Intraocular unit; - Behind-the-ear unit; - A communication link configured to provide an electrical connection between the in-ear unit and the post-auricular unit; - A processor unit configured to receive amplified biological response signals via a communication link; One or more of the multiple electrode units are located in the in-ear unit, and the processor unit is located in the behind-ear unit of the hearing aid.

11. The hearing aid according to claim 10, wherein, A communication link is either a communication bus or a wireless communication link.

12. The hearing aid according to any of the preceding claims, comprising a housing, the housing including a plurality of electrode units and a plurality of electrode channel circuits.

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