Communication method using neural response packet protocol for cochlear implant for measuring neural response

Abstract

A neural response packet protocol for a cochlear implant for measuring a neural response minimizes a communication error, which can be generated in a cochlear implant system, by flawlessly transmitting data by means of a load shift keying (LSK) method. In addition, in an embodiment, the stability of communication is enhanced by solving a cumulative time error problem due to continuous transmission of '0'. In addition, in an embodiment, power can be saved by supplying power to an element of an external device only during a back telemetry data reception section. This greatly reduces power consumption due to the characteristics of the cochlear implant system in which forward transmission is main data transmission, thereby contributing to extending the lifespan of a battery of the device or minimizing power consumption of the external device. In addition, in an embodiment, by providing a protocol supporting various sampling rates, it is possible to collect various biometric signals from high-speed sampling (e.g., 40 kHz) to low-speed sampling (e.g., 300 Hz). This makes it possible to select an appropriate sampling rate according to the type of a neural signal, thereby enabling more accurate neural signal analysis.

Description

Communication method using a neural response packet protocol for cochlear implants to measure neural responses

[0001] The present disclosure relates to a communication method using a neural response packet protocol for a cochlear implant, and specifically, to a neural response packet protocol for a cochlear implant for transmitting biosignals of various periods from an internal unit to an external unit.

[0002] Unless otherwise indicated in this specification, the contents described in this section are not prior art for the claims of this application, and are not to be recognized as prior art simply because they are included in this section.

[0003] A cochlear implant is a device that provides hearing to patients with severe sensorineural hearing loss or total deafness due to inner ear damage by electrically stimulating the auditory nerve. Fig. 1 is a diagram illustrating a cochlear implant. As shown in Fig. 1, the cochlear implant converts a voice signal into neural stimulation information from an external voice processor and transmits it to an internal implant via wireless communication. Subsequently, the internal implant converts the neural signal information into neural stimulation signals and transmits them to a neural electrode unit containing multiple stimulation electrodes, and

[0004] The neural stimulation signal from the stimulation electrode in the neural electrode unit directly stimulates the auditory nerve, enabling the user to perceive sound. The external voice processor and the internal implant transmit data via wireless power transmission and bidirectional wireless communication. While the general population perceives sound through a sound transmission pathway including the eardrum, ossicles, and cochlea, the cochlear implant perceives sound through Path A illustrated in Fig. 1. The external voice processor converts the voice signal into neural stimulation information and transmits the converted neural stimulation information through Path A. Path A is a pathway that includes the external voice processor, the neural stimulator, and the neural electrode unit.

[0005] Figure 2 is a diagram showing the configuration of the external voice processor and the internal unit of a cochlear implant. Referring to Figure 2, the external voice processor of the cochlear implant is configured to include a voice processing chip and a conversion chip (protocol conversion chip). The internal unit of the cochlear implant is configured to include a stimulation chip. In near-field communication using an inductive link for data transmission, data is typically transmitted using the ASK or FSK method.

[0006] Due to their nature, inductive links have the characteristic that the power at the receiving end is not constant, as power efficiency changes with distance. Furthermore, since the power driving part in an inductive link is located in the external unit, power-intensive communication methods cannot be used to transmit data via back telemetry from the internal unit that receives and uses the power. For this reason, most implant systems primarily use the LSK method, which transmits data by changing the Q value of the receiving resonator. The LSK method is a well-known technique that communicates by changing the Q value of the inductive link over a short period to introduce small changes in power efficiency; it is a communication method that utilizes the phenomenon where the voltage of the external unit's coil changes when the Q value changes.

[0007] When transmitting data using the LSK method, a fixed time period is used to determine the data cycle from the external unit. In other words, when the external unit receives data, it recognizes it as '1' if received within a specific cycle and '0' if data is not received within that cycle, thereby enabling data transmission to the external unit without significantly reducing the power transfer efficiency to the internal unit.

[0008] Theoretically, cochlear implant systems can measure various biosignals such as eABR, eCAP, eCEP, and eMLR. Since the period of biosignals measured by cochlear implant systems varies from hundreds of microseconds to hundreds of milliseconds, an efficient transmission protocol is required for real-time back telemetry data transmission according to various sampling rates for measurement.

[0009] A neural response packet protocol for a cochlear implant for measuring neural responses according to an embodiment provides a data protocol related to a method of transmitting data intact using the Load Shift Keying (LSK) method, which is a method that uses less power to transmit back telemetry data.

[0010] In addition, in the embodiment, when transmitting '0' using the LSK method, the sequence of '0's is encoded in the back telemetry protocol so that the sequence of '0's does not exceed three, so that communication errors do not occur due to accumulated time errors caused by the constant time period becoming too long, and then transmitted to an external device.

[0011] In addition, in the embodiment, to provide a protocol capable of supporting various sampling rates of biosignals acquired from a cochlear implant system, a pause token is transmitted to utilize the characteristic that the time between samples becomes longer when the sampling rate slows down. Through this, when the time between measured samples becomes long, the communication connection is maintained, but a period without data transmission is allowed in the protocol. During this period, '0's are physically received continuously, and the protocol ensures that these incoming '0's are not recognized as data transmission. Accordingly, by enabling the internal device to transmit data simultaneously with measurement, the need for a buffer to store data internally is eliminated, and by recognizing the continuous '0's only during the data transmission period, transmission errors caused by link fluctuations can be prevented.

[0012] In addition, the embodiment supports more efficient power control by applying power to the components of the external device only during the period when back telemetry data is received from the external device, so that forward transmission from the external device to the internal device is the main data transmission.

[0013] The cochlear implant based on the neural response packet protocol according to the embodiment supports sampling at different sampling rates during a variable measurement time of 1.5 ms to 300 ms so as to acquire various neural signals such as eCAP, eABR, and eCEP through the cochlear implant NRP protocol defined in this patent. In the embodiment, a pause token is provided in the protocol during sampling so that the stimulation chip supports sampling at a low sampling rate (e.g., 300 Hz) as well as a high sampling rate (e.g., 40 kHz) depending on the type of neural signal to be measured, even with a small internal buffer.

[0014] However, the problem to be solved according to the above embodiment is not limited only to that mentioned above.

[0015] A neural response packet protocol for a cochlear implant for measuring a neural response according to an embodiment acquires a neural signal by performing sampling in a preset variable interval through a Pause Token, which informs an external device of the transmission protocol that it will stop data transmission for a certain period of time, wherein the variable interval includes a sampling rate of 300 Hz to 40 kHz, and the neural signal may include eCAP (electrically evoked Compound Action Potential), eABR (electrically evoked Auditory Brainstem Response), and eCEP (electrically evoked Cortical Evoked Potential), which are electrical signals generated by stimulation of the cochlear implant.

[0016] In addition, when an external device requests a register read from an internal device, it may transmit a preamble twice in succession, then transmit a frame boundary, and then transmit a pause token or data.

[0017] Additionally, the internal device can pause communication during the idle time after transmitting the pause token, and then resume communication by transmitting the frame boundary when data is ready at any given time.

[0018] In addition, when the Analog-to-Digital Converter (ADC) is in low-speed sampling mode, the internal device can transmit the frame boundary after two consecutive preambles and the pause token, and then transmit the frame boundary and the data when the data is ready. When the ADC is in high-speed sampling mode, the internal device can transmit the frame boundary after two consecutive preambles and then transmit the data immediately.

[0019] In addition, the low-speed sampling mode and high-speed sampling mode of the ADC can be determined according to the neural signal sampling rate.

[0020] In addition, the high-speed sampling mode may include a sampling rate of 40 kHz or 20 kHz, and the low-speed sampling mode may include a sampling rate of 300 Hz to 10 kHz.

[0021] In addition, the protocol sequence transmitted by the internal device includes two preambles and frame boundaries when an error occurs in the ADC operation after the internal device starts measuring the neural signal, or when an error occurs in the measurement operation due to the external device sending an incorrect neural signal measurement sequence. Depending on the situation of the internal device, an abolition token may be transmitted immediately, a pause token and an abolition token may be transmitted, or a pause token, an idle time, and an abolition token may be transmitted.

[0022] In addition, the protocol sequence transmitted by the internal device can terminate back telemetry communication by transmitting the frame boundary twice in succession.

[0023] The communication method using the neural response packet protocol for cochlear implants to measure neural responses as described above minimizes communication errors that may occur in the cochlear implant system by transmitting data intact through the Load Shift Keying (LSK) method.

[0024] In addition, the embodiment improves communication stability by resolving the problem of accumulated time error caused by the continuous transmission of '0'.

[0025] In addition, in the embodiment, power can be saved by supplying power to the external device only during the back telemetry data reception period. This significantly reduces power consumption due to the characteristics of the cochlear implant system, where forward transmission is the primary data transmission, thereby contributing to extending the battery life of the device or minimizing the power consumption of the external device.

[0026] In addition, the embodiment provides a protocol that supports various sampling rates, allowing the sampling rate to be used from high-speed sampling (e.g., 40 kHz) to low-speed sampling (e.g., 300 Hz), thereby enabling the collection of various biological signals. This allows for the selection of an appropriate sampling rate depending on the type of neural signal, thereby enabling more accurate neural signal analysis.

[0027] In addition, the embodiment ensures that data is not transmitted while maintaining the communication connection when data transmission is unnecessary by transmitting a pause token when the time between samples becomes prolonged. This improves communication efficiency and reduces the system's hardware requirements by eliminating the need for a large internal buffer.

[0028] In addition, through the embodiment, the protocol is implemented to have diversity even with a small number of tokens, thereby enabling the internal to process data at various sampling rates even with a small internal buffer.

[0029] The neural response packet protocol for a cochlear implant for measuring neural responses according to the embodiment contributes to improving the performance of a cochlear implant system, increasing power efficiency, and enhancing the accuracy and versatility of neural signal measurement.

[0030] The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the configuration of the invention described in the detailed description of the invention or the claims.

[0031] Figure 1 is a drawing showing a cochlear implant.

[0032] FIG. 2 is a diagram showing a data transmission channel of the external voice processor and internal unit configuration of a cochlear implant according to an embodiment.

[0033] FIG. 3 is a diagram illustrating bit stuffing for 4B5B data encoding and NRP according to an embodiment.

[0034] FIG. 4 is a drawing showing a token conversion diagram according to an embodiment.

[0035] FIG. 5 is a drawing for explaining an operational example of a neural response packet protocol according to an embodiment.

[0036] FIG. 6 is a diagram showing an example of ABORT TOKEN transmission according to an embodiment.

[0037] Figure 7 is a diagram illustrating the back telemetry power control process.

[0038] FIG. 8 is a drawing showing a sense amplifier according to an embodiment.

[0039] FIG. 9 is a drawing showing a Power Level Measurement Block according to an embodiment.

[0040] A neural response packet protocol for a cochlear implant for measuring a neural response according to an embodiment acquires a neural signal by performing sampling in a preset variable interval through a Pause Token, which informs an external device of the transmission protocol that it will stop data transmission for a certain period of time, wherein the variable interval includes a sampling rate of 300 Hz to 40 kHz, and the neural signal may include eCAP (electrically evoked Compound Action Potential), eABR (electrically evoked Auditory Brainstem Response), and eCEP (electrically evoked Cortical Evoked Potential), which are electrical signals generated by stimulation of the cochlear implant.

[0041] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Identical or similar components regardless of drawing symbols are assigned the same reference number, and redundant descriptions thereof will be omitted. The suffixes "module" and "part" used for components in the following description are assigned or used interchangeably solely for the ease of drafting the specification and do not inherently possess distinct meanings or roles. Furthermore, in describing embodiments disclosed in this specification, if it is determined that a detailed description of related prior art could obscure the essence of the embodiments disclosed in this specification, such detailed description will be omitted. Additionally, the attached drawings are intended only to facilitate understanding of the embodiments disclosed in this specification; the technical concept disclosed in this specification is not limited by the attached drawings, and it should be understood that they include all modifications, equivalents, and substitutions that fall within the spirit and technical scope of the present invention.

[0042] Terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but said components are not limited by said terms. These terms are used solely for the purpose of distinguishing one component from another.

[0043] When it is stated that one component is "connected" or "connected" to another component, it should be understood that while it may be directly connected or connected to that other component, there may also be other components in between. On the other hand, when it is stated that one component is "directly connected" or "directly connected" to another component, it should be understood that there are no other components in between.

[0044] In this application, terms such as “comprising” or “having” are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0045] In this specification, the term "part" includes a unit realized by hardware, a unit realized by software, and a unit realized using both. Additionally, one unit may be realized using two or more hardware, and two or more units may be realized by one hardware.

[0046] Some of the operations or functions described herein as being performed by a terminal, device, or device may instead be performed by a server connected to said terminal, device, or device. Likewise, some of the operations or functions described as being performed by a server may also be performed by a terminal, device, or device connected to said server.

[0047] Hereinafter, the present invention will be described in detail with reference to the attached drawings.

[0048] The neural response packet protocol for a cochlear implant for measuring neural responses according to the embodiment enables various transmissions to be performed without errors using a small number of tokens. In the embodiment, since the same token is used for the preamble token and the pause token, the meaning of the token changes depending on the state of transition after transmission begins, thereby enabling smooth data communication even with a small number of tokens.

[0049] FIG. 2 is a diagram showing the data transmission channel of the external voice processor and internal device configuration of an artificial cochlea according to an embodiment.

[0050] Referring to FIG. 2, the artificial cochlea according to the embodiment includes an external voice processor (10) and an internal unit (20), and the external voice processor (10) may be configured to include a voice processing chip (11) and a protocol conversion chip (12). In the embodiment, the internal unit (20) may be configured to include a stimulation chip (21).

[0051] In the embodiment, the external voice processor (10) converts a voice signal into neural stimulation information, and the internal unit (20) converts the neural stimulation information into a neural stimulation signal and transmits it to a neural electrode. In the embodiment, the external voice processor (10) includes a voice processing chip (11) that controls the internal unit (20) and a protocol conversion chip (12) that performs encoding and decoding.

[0052] In the embodiment, the voice processing chip (11) controls the internal unit (20) and the protocol conversion chip (12) and determines the status of the protocol conversion chip (12). The protocol conversion chip (12) performs encoding and decoding according to the communication interface. In the embodiment, the stimulation chip (21) of the internal unit (20) operates the internal unit (20) and measures the neural response signal according to the electrical stimulation. In the embodiment, the protocol conversion chip (12) of the external voice processor (10) and the stimulation chip (21) of the internal unit (20) communicate through an inductive link. In the embodiment, communication of the cochlear implant based on the Neural Response Packet (NRP) protocol is performed for backward communication.

[0053] A neural response packet protocol for a cochlear implant for measuring neural responses according to an embodiment provides a data protocol related to a method of transmitting data intact using the Load Shift Keying (LSK) method, which is a method that uses less power to transmit back telemetry data.

[0054] In addition, in the embodiment, when transmitting '0' using the LSK method, the sequence of '0's is encoded in the back telemetry protocol so that the sequence of '0's does not exceed three, so that communication errors do not occur due to accumulated time errors caused by the constant time period becoming too long, and then transmitted to an external device.

[0055] In addition, in the embodiment, to provide a protocol capable of supporting various sampling rates of biosignals acquired from a cochlear implant system, a pause token is transmitted to utilize the characteristic that the time between samples becomes longer when the sampling rate slows down. Through this, the protocol ensures that the communication connection is maintained but data is not transmitted when the time between measured samples becomes long. Accordingly, by enabling the internal device to transmit data simultaneously with measurement, the need to have a buffer for storing data internally is eliminated.

[0056] In addition, the embodiment supports more efficient power control by applying power to the components of the external device only during the period when back telemetry data is received from the external device, so that forward transmission from the external device to the internal device is the main data transmission.

[0057] The cochlear implant based on the neural response packet protocol according to the embodiment samples for a variable interval of 1.5ms to 300ms to acquire various neural signals such as eCAP, eABR, and eCEP through the cochlear implant NRP protocol. In the embodiment, a pause token is provided during sampling so that the stimulation chip can sample at a low sampling rate (e.g., 300Hz) as well as a high sampling rate (e.g., 40kHz) depending on the type of neural signal to be measured, even with a small internal buffer.

[0058] In the embodiment, the stimulation chip (21) acquires neural signals including eCAP, eABR, and eCEP through the NRP protocol of the cochlea by sampling, and samples the neural signals in a sampling range including a set low sampling frequency to a high sampling frequency through a pause token during sampling.

[0059] The NRP protocol according to the embodiment provides a pause token to facilitate sampling during a variable interval of 1.5ms to 300ms so as to acquire various neural signals (eCAP, eABR, eCEP, etc.). Through this, the stimulation chip supports sampling at a low sampling rate (e.g., 300Hz) as well as a high sampling rate (e.g., 40kHz) depending on the type of neural signal to be measured, even with a small internal buffer.

[0060] In addition, the NRP protocol according to the embodiment allows for the design to avoid having to store a separate large buffer in the stimulation chip through a pause token. Since the method of measuring biosignals involves sampling the biosignals at a constant sampling rate, if the external voice processor is not synchronized in a specific way, a large buffer is required to store data in the stimulation chip to sample for a long period. Accordingly, in order to design a small buffer size within the stimulation chip while supporting various sampling rates, it is necessary to inform the external voice processor via a pause token in the transmission protocol that data transmission will be temporarily paused. If the external voice processor receives data only at a constant transmission speed, the only method available is to store the data in the buffer of the stimulation chip within the internal device when the rate is slow and then transmit it to the external voice processor all at once.

[0061] In addition, in the embodiment, when transmitting data, the back telemetry decoder in the external receiver counts the zeros based on the bit data period determined by itself for the sections where zeros are consecutive; therefore, if the sequence of zeros becomes long, a problem occurs in which zeros are incorrectly counted. Accordingly, in the embodiment, errors caused by inductive link variation are overcome by transmitting the data encoded so that the sequence of zeros is limited to three or fewer.

[0062] In addition, in the embodiment, during the pause period from the time the pause token is transmitted until the frame boundary to resume data transmission is transmitted, it may be thought that there are three or more consecutive zeros infinitely, but since the sequence of zeros at this time is not a data transmission section in the protocol, it is a section that is not recognized by the external device that is the receiver, so it has no meaning as data.

[0063] FIG. 3 is a diagram illustrating bit stuffing for 4B5B data encoding and NRP according to an embodiment.

[0064] Referring to FIG. 3, bit stuffing is an encoding method used to ensure that the receiving end can distinguish the protocol token from the data. Since protocol token signals consist of six or more consecutive 1s, if there are six or more consecutive 1s during data transmission, the protocol token cannot be distinguished from the data. Therefore, when sending data, if five consecutive 1s appear, a 0 is unconditionally inserted, allowing the receiving end to distinguish it from the protocol token. As illustrated in FIG. 3, if 01001 / 0111 / 1101 is encoded for transmission and then 01001 / 01111 / 11011 is transmitted, the underlined part cannot be distinguished from the frame boundary token, 01111110, because there are six consecutive 1s. When bit stuffing is applied, it becomes 01001 / 01111 / 101011, making it distinguishable from the frame boundary token. The 4B5B data encoder encodes such that there are no more than three consecutive zeros, even when bit stuffing is taken into account. Data created with bit stuffing applied in this way is decoded at the receiving end by removing zeros while taking bit stuffing into account.

[0065] In addition, in the embodiment, the data being encoded is designed so that a maximum of two consecutive zeros can be formed by a continuous combination, so the case where three zeros are transmitted occurs only when bit stuffing is applied. For example, if one intends to transmit data such as 0001 / 0000 / 0001, it is encoded as 01001 / 11110 / 01001. Since there are five consecutive zeros, bit stuffing is applied to insert additional zeros, so the final data transmitted to the receiving end is 01001 / 11110 / 0 / 01001. In this case, there are three consecutive zeros in the underlined part, and this is the case where the maximum number of zeros is.

[0066] FIG. 4 is a diagram showing a token transition diagram according to an embodiment.

[0067] Referring to FIG. 4, the protocol token sequence transmitted by the internal device in the embodiment may consist of a preamble, a frame boundary, an abort token, an idle time, data, etc. The number of bits of data in the protocol is not specified. In the embodiment, the internal device of the cochlear implant may acquire neural signals by performing sampling in a variable interval according to a preset sampling rate through a Pause Token, which informs the external device in the transmission protocol that it intends to temporarily stop data transmission. In the embodiment, the variable interval includes a sampling rate of 300 Hz to 40 kHz, and the neural signals may include eCAP (electrically evoked Compound Action Potential), eABR (electrically evoked Auditory Brainstem Response), eCEP (electrically evoked Cortical Evoked Potential), etc., which are electrical signals generated by stimulation of the cochlear implant.

[0068] In an embodiment, the preamble token may be set to 01111111, the pose token to 01111111, the frame boundary to 01111110, and the abolt token to 11111111, but is not limited thereto.

[0069] In the embodiment, the NRP protocol is designed to be a flexible protocol with the smallest possible number of tokens, and the defined tokens are selected to have as many 1s as possible so that it is easy to identify the period when the receiving side receives data bits, thereby minimizing transmission errors caused by error accumulation.

[0070] In the embodiment, as a condition for the BackTel protocol to start, the preamble token is transmitted twice in succession only once at the start of the protocol.

[0071] In the embodiment, an Abort token is transmitted or a Frame Boundary (FB) is transmitted twice in succession as a condition for the BackTel protocol to end. In the embodiment, data transmission begins with a Preamble token and is transmitted only once at the start of the protocol's transition diagram. After that, no Preamble token is transmitted until the transmission ends. Tokens that appear during transmission are recognized as Pause tokens. In the embodiment, since the same token is used for the Preamble token and the Pause token, the meaning of the token changes depending on the transition state after the transmission begins. Accordingly, if an Abort token or Frame Boundary token indicating the end of transmission is not transmitted twice during transmission, but a Preamble token is transmitted twice in the middle, a protocol error occurs. In other words, the protocol has been violated. In the embodiment, the end of transmission is when an Abort token or a Frame Boundary token is transmitted twice in succession without a Preamble token and a Frame Boundary token.

[0072] In the embodiment, when an external device receives a condition that the back telemetry (BackTel) protocol ends, it puts the back telemetry (BackTel) related analog components and logic (e.g., receiver configuration blocks) into low-power mode.

[0073] Referring to FIG. 4, in the protocol sequence provided in the embodiment, if a frame boundary is transmitted consecutively after the frame boundary transmission, it indicates the termination of transmission. This serves as a signal to terminate data transmission because there is no data between the frame boundaries. In the embodiment, biometric information can be transmitted from an internal unit to an external unit by transmitting data between the frame boundaries. Additionally, the transmission of an abolition token signifies abnormal termination. In the embodiment, transmitting an abolition token indicates that an error has occurred in the internal unit or that it is not ready to send data, and the sender and receiver transmit the abolition token to perform the abnormal termination normally.

[0074] Hereinafter, to explain the rules of the neural response packet protocol for a cochlear implant according to the embodiment, the transition states for the positions where each token can appear are described. Any tokens that do not appear in the aforementioned positions below are considered transmissions that violate the protocol, so the receiving side forcibly terminates the transmission and ignores all subsequent backward transmissions.

[0075] Referring to FIG. 4, in the embodiment, the pause token may appear only after the frame boundary token. This signifies that transmission is temporarily suspended until the next frame boundary is transmitted after the pause token is sent. In other words, since the external device does not count '0' using the bit cycle until the next frame boundary is sent, a sequence of '0's is not recognized. Since this is a period where transmission is stopped, incoming '0's are meaningless. In the embodiment, data may appear only after the frame boundary. The number of bits in this data is not specified. Until the next frame boundary token appears, it is all recognized as data by the receiving side. In the embodiment, the abolition token may appear after the frame boundary token. In the embodiment, the abolition token may appear immediately after the pause token. In the embodiment, the abolition token may appear in the middle of the idle time to indicate the end of transmission instead of the frame boundary token. In the embodiment, the frame boundary token may appear after the preamble token or the pause token. In the embodiment, the frame boundary token may follow the data. In the embodiment, the frame boundary token may follow immediately after the frame boundary token. In this case, it is recognized by the receiver as a token sequence indicating the end of transmission. In the embodiment, the preamble token may appear only after the preamble token. A token sequence consisting of two consecutive preamble tokens is recognized by the receiver as a token sequence indicating the start of protocol transmission. In the embodiment, the preamble token sequence cannot appear prior to the end of the protocol.

[0076] FIG. 5 is a diagram illustrating an operational example of a neural response packet (NRP) protocol according to an embodiment.

[0077] Referring to FIG. 5, in the embodiment, if an ADC error occurs when the internal unit powers on, the preamble is transmitted twice in succession at the start of neural signal measurement, followed by the frame boundary and the abandon token. Additionally, in the embodiment, if an error occurs during neural signal measurement by the internal unit, the preamble is transmitted twice in succession, followed by the frame boundary, the pause token, and the abandon token. When the internal unit requests data reading from the external unit, the preamble is transmitted twice in succession, followed by the pause token or data. Furthermore, if the Analog-to-Digital Converter (ADC) is in low-speed sampling mode, the internal unit transmits the preamble twice in succession, followed by the frame boundary and the pause token, followed by an idle period, and then transmits the frame boundary and data again; this transmission method is repeated until the protocol ends. When the ADC is in high-speed sampling mode, the transmission method of transmitting the preamble twice in succession, then transmitting the frame boundary and data, then transmitting the frame boundary and data again, is repeated until the protocol ends.

[0078] Additionally, in the embodiment, when the internal unit is in register read mode, it starts the protocol by transmitting a preamble twice consecutively to the external unit, transmits a frame boundary, and terminates the protocol by transmitting a frame boundary twice consecutively after data transmission. In the embodiment, the low-speed mode and high-speed mode of the ADC are determined according to the neural signal sampling rate. In the embodiment, the high-speed mode includes a sampling rate of 40 kHz and 20 kHz, and the low-speed mode includes a sampling rate of 300 Hz to 10 kHz.

[0079] In addition, in the embodiment, when the transmission from the internal unit to the external unit is finished without data, the transmission is performed by transmitting the preamble twice in succession, transmitting the frame boundary, and transmitting the frame boundary again.

[0080] Figure 6 is a diagram showing an example of ABORT TOKEN transmission according to an embodiment.

[0081] Referring to FIG. 6, in the embodiment, when an error occurs after verifying the ADC operation upon power-on of the internal device, or when an error occurs because an incorrect neural signal measurement sequence is sent from the external device, two preambles and frame boundaries are transmitted, followed by the transmission of an abandon token. Additionally, in the embodiment, after power-on of the internal device, if normal ADC operation is verified but an error occurs during impedance measurement or biosignal measurement including eCAP, two preambles and frame boundaries are transmitted, followed by the transmission of a pause token and an abandon token, or a port token, and an idle period during which transmission is temporarily paused, followed by the transmission of an abandon token.

[0082] In the embodiment, the neural response packet protocol transmits an ABORT TOKEN from the internal unit when an internal unit abnormality is detected. The internal unit abnormality according to the embodiment may include cases where an error occurs after verifying ADC operation upon power-on, cases where an error occurs due to the transmission of an incorrect neural signal measurement sequence from an external voice processor, and cases where ADC operation is verified upon power-on but an error occurs during impedance measurement or eCAP measurement.

[0083] Figure 7 is a diagram illustrating the back telemetry power control process.

[0084] Referring to FIG. 7, the neural response packet protocol according to the embodiment is coupled with the NP2 protocol and applies power to the relevant analog hardware via a Power Enable (PWREN) signal within the external device just before the arrival of back telemetry data, so that back telemetry data can be received. Subsequently, until a backTel NOP defined in the NP2 protocol arrives to receive back telemetry data, the external device maintains the back telemetry-related digital blocks within the external device in a power-down state, and powers on the digital section only during the interval when the backTel NOP arrives to perform decoding. In addition, the backTel-related hardware must be implemented so that it turns off only after the backTel protocol being transmitted is completely processed upon entering low power. At this time, the backTel FSM in the external device guarantees the timing related to the off state.

[0085] In addition, the back telemetry FSM processing the neural response packet protocol according to the embodiment ensures that forward telemetry cannot be sent out while backward telemetry is coming in, because backward telemetry and forward telemetry transmit data by physically sharing the same inductive link. That is, backward and forward telemetry cannot be transmitted simultaneously at the same timing. Accordingly, as illustrated in FIG. 7, since backward telemetry is received after a specific time following the sending of forward telemetry, the embodiment utilizes the aforementioned characteristics to implement a method of powering on the digital hardware related to back telemetry only during the back telemetry period using a timing method that utilizes a back telemetry NOP (BT-NOP) packet in the NP2 protocol defined in the NP2 interface, which is the internal communication interface of the external voice processor, thereby performing power control to minimize the power consumption of the external voice processor.

[0086] The cochlear implant based on the neural response packet protocol according to the embodiment supports sampling at a variable high sampling rate (e.g., 40 kHz) as well as a low sampling rate (e.g., 300 Hz) depending on the type of neural signal to be measured, even with an internal buffer of a small size for the stimulation chip. In addition, the cochlear implant based on the neural response packet protocol according to the embodiment performs power control to minimize power consumption of the external voice processor by implementing a method of powering on back telemetry-related hardware only during the back telemetry period using a back telemetry NOP (BT-NOP) packet at the internal communication interface of the external voice processor.

[0087] Hereinafter, a closed-loop power control method through back-telemetry of an implantable device according to an embodiment is described. In the embodiment, power supplied from an external device via an inductive link is received by an LC resonator of an internal device and supplied to an internal device chip. This power is used to operate the internal device chip, but due to the characteristics of electronic devices, it cannot operate at voltages that are too high or too low. For this reason, a Zener diode is generally used to determine the maximum allowable voltage. However, if the power from the received inductive link is excessive and the current flowing through the Zener diode becomes large, the power that is not used by the internal device and is wasted increases. As a result, the external device unnecessarily supplies power.

[0088] For this reason, implantable medical devices that receive power from an external source, such as most cochlear implants, utilize communication with an external unit to form a closed loop for power control at a higher level, thereby regulating the amount of power received internally by adjusting the amount of power supplied externally.

[0089]

[0090] In the embodiment, power is measured internally, and to compensate for the potential for unstable voltage due to the characteristics of the device receiving power from an external source, the external device is configured to stably supply only the appropriate power required by the internal device.

[0091] FIG. 8 is a diagram showing a sense amplifier according to an embodiment. Referring to FIG. 8, the power level measurement block is configured to include an inductive link, a Zener diode, and a power level boundary detector. The power level boundary detector includes a sense amplifier, a voltage comparator, and an internal voltage measuring unit.

[0092] A sense amplifier is a device that converts current measurements into voltage measurements. The magnitude of the voltage generated in the inductive link is clamped and limited by a Zener diode so that it does not exceed a specific voltage, and it is used to generate a voltage corresponding to the current flowing through this Zener diode. This voltage is used to determine the upper bound of the received power level.

[0093] In the embodiment, the internal voltage measuring unit is a block that measures whether the internal 5V power supply of the chip has stabilized. It measures the internal 5V voltage of the power level boundary detector (broadly speaking, the power level measuring block), outputs "1" when the internal 5V voltage has stabilized to 4V or higher, and outputs "0" if it has not yet stabilized to 4V or higher. Only when the internal 5V power level voltage is stabilized can it be assured that the external unit is supplying power sufficient for the internal chip to operate, and this output is used to determine the lower bound of the received power level. The power state of the internal unit is controlled to be stably maintained between the upper bound of the power level and the lower bound of the power level.

[0094] FIG. 9 is a diagram showing a Power Level Measurement Block according to an embodiment.

[0095] As previously explained, the upper and lower limit signals are signals used to determine the upper and lower limits of the power level measured in the inductive link of the internal device. The Back Telemetry Enable signal is a signal generated within the chip when Back Telemetry is initiated by a command received by the internal device chip through a communication protocol; it is a signal that maintains "1" during the Back Telemetry transmission period and "0" during the period when the Back Telemetry transmission ends.

[0096] This back telemetry enable signal is used to generate the High Threshold Indicator and Low Threshold Indicator, which are the final output signals of the Power Measurement Block. When the High Threshold Indicator is "1," it indicates that the power state is excessive, and when the Low Threshold Indicator is "0," it indicates that the power state is insufficient. Under normal conditions, the High Threshold Indicator is "0" and the Low Threshold Indicator is "1." However, since actual operation operates with slightly more power than the appropriate power, the High Threshold Indicator is optimized to operate in a random state between "1" and "0" whenever measurement is taken. In the embodiment, these two signal values ​​are transmitted to the external unit via the back telemetry protocol, allowing the external unit to check the power reception status of the internal unit.

[0097] The operation process will be explained below using the table (Truth Table) shown in FIG. 9.

[0098] If the power level received by the internal unit fluctuates between 1 and 0 because it is high or low near the lower bound, the data received by the external unit will randomly measure 1 or 0. In this case, since reading the internal unit's status only once at a specific point in time could lead the external unit to misjudge the amount of power supplied to the internal unit, it is essential to enable the external unit to detect if the power level deviates from the appropriate range even once. For this reason, the configuration involves re-measuring based on the point where the back telemetry ends, and maintaining the value at 0 if the lower bound has been lowered even once until the start of the next back telemetry.

[0099] Similarly, to prevent the High Threshold Indicator from being measured unstably due to the power level received by the internal unit fluctuating high or low near the upper bound, a new measurement is started based on the point where back telemetry ends, and if the value has risen above the upper bound even once, it is maintained at 1. This High Threshold Indicator optimizes the amount of power supplied to the internal unit by finding a power level that intentionally causes "1" or "0" to repeat. This is intentionally designed so that the external unit can find a power level where the current flowing through the Zener diode can be matched near the desired target current, as the current flowing through the Zener diode becomes the excess energy that can make up for the current deficit in the internal unit caused by power fluctuations in the inductive link.

[0100] The Low Threshold Indicator is updated when the Lower Bound signal transitions from 1 to 0, and the measured value remains unchanged until the new Back Telemetry ends. The High Threshold Indicator operates in the same way, but differs only in that the part updated when the Upper Bound signal transitions from 0 to 1.

[0101] Since this hardware configuration enables the capture of power fluctuations at a specific point in time like a snapshot, controlling with the process mentioned above allows information regarding power fluctuations caused by the characteristics of the inductive link when receiving internal power to be sent to the external device via back telemetry, enabling the external device to identify this state. Power fluctuations can occur due to changes in the coupling coefficient between coils caused by the distance between devices or twisting of the alignment between the inductive link coils.

[0102] Accordingly, in the embodiment, the hardware supports the formation of a closed loop at a higher level by linking with the software through the aforementioned method, thereby enabling the external unit to supply optimized power to the internal unit to such an extent that power fluctuations of the induction link do not affect the operation of the internal unit.

[0103] The neural response packet protocol for cochlear implants for measuring neural responses as described above minimizes communication errors that may occur in the cochlear implant system by transmitting data intact through the Load Shift Keying (LSK) method.

[0104] In addition, the embodiment improves communication stability by resolving the problem of accumulated time error caused by the continuous transmission of '0'.

[0105] In addition, in the embodiment, power can be saved by supplying power to the external device only during the back telemetry data reception period. This significantly reduces power consumption due to the characteristics of the cochlear implant system, where forward transmission is the primary data transmission, thereby contributing to extending the battery life of the device or minimizing the power consumption of the external device.

[0106] In addition, the embodiment provides a protocol that supports various sampling rates, allowing for the collection of various biological signals ranging from high-speed sampling (e.g., 40 kHz) to low-speed sampling (e.g., 300 Hz). This enables the selection of an appropriate sampling rate depending on the type of neural signal, thereby enabling more accurate neural signal analysis.

[0107] In addition, the embodiment ensures that data is not transmitted while maintaining the communication connection when data transmission is unnecessary by transmitting a pause token when the time between samples becomes prolonged. This improves communication efficiency and reduces the system's hardware requirements by eliminating the need for a large internal buffer.

[0108] In addition, the embodiment is implemented so that the protocol can have diversity even with a small number of tokens, thereby enabling the internal device to process data at various sampling rates even with a small internal buffer.

[0109] The neural response packet protocol for a cochlear implant for measuring neural responses according to the embodiment contributes to improving the performance of a cochlear implant system, increasing power efficiency, and enhancing the accuracy and versatility of neural signal measurement.

[0110] The disclosed content is merely illustrative and can be modified and implemented in various ways by a person skilled in the art without departing from the gist of the claim in the patent claims; therefore, the scope of protection of the disclosed content is not limited to the specific embodiments described above.

[0111] A communication method using a neural response packet protocol for cochlear implants to measure neural responses minimizes communication errors that may occur in a cochlear implant system by transmitting data intact through the Load Shift Keying (LSK) method.

[0112] In addition, the embodiment improves communication stability by resolving the problem of accumulated time error caused by the continuous transmission of '0'.

[0113] In addition, in the embodiment, power can be saved by supplying power to the external device only during the back telemetry data reception period. This significantly reduces power consumption due to the characteristics of the cochlear implant system, where forward transmission is the primary data transmission, thereby contributing to extending the battery life of the device or minimizing the power consumption of the external device.

[0114] In addition, the embodiment provides a protocol that supports various sampling rates, allowing the sampling rate to be used from high-speed sampling (e.g., 40 kHz) to low-speed sampling (e.g., 300 Hz), thereby enabling the collection of various biological signals. This allows for the selection of an appropriate sampling rate depending on the type of neural signal, thereby enabling more accurate neural signal analysis.

[0115] In addition, the embodiment ensures that data is not transmitted while maintaining the communication connection when data transmission is unnecessary by transmitting a pause token when the time between samples becomes prolonged. This improves communication efficiency and reduces the system's hardware requirements by eliminating the need for a large internal buffer.

[0116] In addition, through the embodiment, the protocol is implemented to have diversity even with a small number of tokens, thereby enabling the internal to process data at various sampling rates even with a small internal buffer.

[0117] The neural response packet protocol for a cochlear implant for measuring neural responses according to the embodiment contributes to improving the performance of a cochlear implant system, increasing power efficiency, and enhancing the accuracy and versatility of neural signal measurement.

[0118] 10: The external voice processor (10) is

[0119] 20: Internal

[0120] 11: Voice processing chip

Claims

1. A communication method using a neural response packet protocol for a cochlear implant for measuring neural responses, wherein the cochlear implant includes an internal unit that collects neural signals and transmits them to an external unit, and an external unit that receives external sounds and transmits them to the internal unit. A communication method using the above protocol is: A step of generating a protocol sequence by combining a preamble token signal, a frame boundary signal, an abandon token signal, a pause token signal, an idle token signal, and a data signal by an internal unit; and The step of transmitting the generated protocol sequence from the internal device to the external device by the internal device; The above preamble token signal is a signal indicating the start of a sequence, and The above frame boundary signal is a signal that prepares to receive subsequent data signals, and The above Abolt token signal is a signal that stops transmission, and The above pause token signal is a signal that temporarily pauses transmission, and The above children token signal is a signal that maintains an idle state, and The data signal is a signal sampled from the neural signal collected by the internal device, and The step of generating the above protocol sequence by an internal unit is: After generating the preamble token signal, the step of generating the first frame boundary signal; and The method includes the step of generating any one of a second frame boundary, an abolition token signal, a pause token signal, and a data signal after generating the first frame boundary signal. In the above protocol sequence, i) In the case where the second frame boundary is generated immediately after the first frame boundary signal, or ii) If an Abolt token is generated, The external device determines that the transmission from the internal device to the external device has ended. Communication method using a neural response packet protocol for cochlear implants.

2. In paragraph 1, the communication method using the above protocol Neural signals are acquired by performing sampling in a preset variable interval through a Pause Token signal, which informs the external unit of the cochlear implant via the transmission protocol that data transmission will be temporarily paused, and The above variable section is It includes a sampling rate of 300Hz to 40kHz, The above neural signal is A communication method using a neural response packet protocol for a cochlear implant, comprising eCAP (electrically evoked Compound Action Potential), eABR (electrically evoked Auditory Brainstem Response), and eCEP (electrically evoked Cortical Evoked Potential), which are electrical signals generated by stimulation of the cochlear implant.

3. In paragraph 1, the step of transmitting the generated sequence from the internal unit to the external unit In the event that a power-on error occurs in the above internal unit, A communication method using a neural response packet protocol in which an internal device transmits a preamble token signal to an external device twice in succession, then transmits a frame boundary, and then transmits an abandon token signal.

4. In claim 1, the step of transmitting the generated sequence from the internal unit to the external unit A neural response packet protocol method for a cochlear implant, wherein if an error occurs during the measurement of a neural signal by the above-mentioned internal device, a preamble token signal is transmitted twice in succession, followed by a pause token signal and an abolition token signal.

5. In paragraph 1, the step of transmitting the generated sequence from an internal unit to an external unit When the above internal device requests data reading from the external device, A communication method using a neural response packet protocol for a cochlear implant, further comprising the steps of transmitting a preamble token signal twice in succession, transmitting a frame boundary signal, and transmitting a pause token signal or data.

6. In paragraph 5, the above internal device When the ADC (Analog-to-Digital Converter) is in low-speed mode, after transmitting the preamble signal twice consecutively, it transmits the frame boundary signal, and then sequentially transmits the pause fork signal and the idle token signal, and The communication method using the above-mentioned neural response packet protocol for cochlear implants A communication method using a neural response packet protocol for a cochlear implant, which further includes the step of transmitting a preamble signal twice consecutively, then transmitting a frame boundary signal and transmitting data when the ADC is in high-speed mode.

7. In paragraph 5, the step of transmitting the generated sequence from the internal unit to the external unit A communication method using a neural response packet protocol for a cochlear implant, further comprising the step of, in the case of register read mode, transmitting a preamble signal twice consecutively to an external device, transmitting a frame boundary signal, and transmitting a frame boundary signal twice consecutively after data transmission.

8. In Paragraph 6, A communication method using a neural response packet protocol for a cochlear implant, wherein the low-speed mode and high-speed mode of the above ADC are determined according to the neural signal sampling rate.

9. In Paragraph 8, A communication method using a neural response packet protocol for a cochlear implant, wherein the high-speed mode has a sampling rate range of 40 kHz to 20 kHz and the low-speed mode has a sampling rate range of 300 Hz to 10 kHz.

10. In paragraph 4, the step of transmitting the generated protocol sequence from the internal unit to the external unit A communication method using a neural response packet protocol for a cochlear implant, further comprising: a step of transmitting an abolition token signal after two preamble and frame boundary signals are transmitted in a protocol sequence transmitted by an internal device, indicating when an error occurred after verifying the ADC operation upon power-on of the internal device or when an error occurred because an external device sent an incorrect neural signal measurement sequence.

11. In paragraph 10, the step of transmitting the generated protocol sequence from the internal unit to the external unit A communication method using a neural response packet protocol for a cochlear implant, further comprising: a step in which, in a protocol sequence transmitted by the internal device, after power-on of the internal device, two preamble signals and a frame boundary signal are transmitted, and a pause token signal and an abandon token signal are transmitted, or a port token signal, an idle signal and an abandon token signal are transmitted, and an error occurs during impedance measurement or biosignal measurement including eCAP after checking the ADC operation.

12. In paragraph 1, the above internal device The LC resonator of the internal unit receives power supplied from the external unit through an inductive link and supplies it to the internal unit chip, and The above power is a communication method using a neural response packet protocol for a cochlear implant, which is used to operate an internal chip.

13. In Paragraph 12, The above internal chip includes a sense amplifier that converts a current measurement into a voltage measurement, and The voltage measured by the sense amplifier is used to determine the upper bound of the received power level, and The internal voltage output of the internal chip is used to determine the lower bound of the received power level, and A communication method using a neural response packet protocol for a cochlear implant, characterized by stably maintaining the power state of the internal device between the upper limit of the power level and the lower limit of the power level.

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