# US 10,764,680 B2 · Microphone system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,764,680 B2 - Document ID: US10764680B2 - Status: Granted - Kind: B2 - Application number: 16/327,345 - Filed: 2017-05-29 - Published: 2019-06-20 - Granted: 2020-09-01 - Earliest claimed: 2016-08-26 - Assignees: Alpha Holdings, Inc. - Applicants: Adtech Co., Ltd. - Inventors: Young Chul Park - Web page: https://patentgrep.com/patent/US10764680B2 ## CPC - H04R 3/007: {Protection circuits for transducers} - H03F 1/26: Modifications of amplifiers to reduce influence of noise generated by amplifying elements - H03F 1/30: Modifications of amplifiers to reduce influence of variations of temperature or supply voltage {or other physical parameters (in differential amplifiers H03F3/45479)} - H03F 3/187: in integrated circuits - H03F 3/211: {using a combination of several amplifiers (H03F3/60 takes precedence)} - H04R 3/00: Circuits for transducers (arrangements for producing a reverberation or echo sound G10K15/08; amplifiers H03F) - H04R 3/06: of electrostatic transducers - H04R 19/04: Microphones (H04R19/01 takes precedence) - H03F 2200/03: the amplifier being designed for audio applications - H04R 2201/003: Mems transducers or their use - H04R 2410/03: Reduction of intrinsic noise in microphones - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) - H03F: AMPLIFIERS ## Abstract Provided is a microphone system insensitive to external noise, and the microphone system includes a microphone sensor that generates sensing data by sensing a change in sound pressure through a sensor bias voltage, a lead-out circuit that provides the sensor bias voltage for operating the microphone sensor, removes noise of the sensing data, and outputs the sensing data, a first pad that connects the microphone sensor and the lead-out circuit to each other and allows the sensor bias voltage to pass therethrough, and a second pad that connects the microphone sensor and the lead-out circuit to each other and allows the sensing data to pass therethrough. ## Claims ### Claim 1 A microphone system comprising: a microphone sensor configured to generate sensing data by sensing a change in sound pressure through a sensor bias voltage; a read-out circuit configured to provide the sensor bias voltage for operating the microphone sensor, and receive and output the sensing data; a first pad configured to connect the microphone sensor and the read-out circuit to each other and allow the sensor bias voltage to pass therethrough; and a second pad configured to connect the microphone sensor and the read-out circuit to each other and allow the sensing data to pass therethrough, wherein the read-out circuit comprises: a first filter unit configured to filter the sensor bias voltage and filter first noise introduced from the first pad; a second filter unit configured to filter second noise introduced from the second pad; and a voltage buffer configured to amplify the sensing data and discharge the first noise or the second noise; wherein the read-out circuit further comprises: a first bias generator configured to generate the sensor bias voltage by amplifying a reference voltage; and a second bias generator configured to provide the voltage buffer with a buffer bias voltage by using a reference current, and wherein the first filter unit comprises: a first filter including a resistor or a capacitor in which one end is connected to an output terminal of the voltage buffer and the second filter unit and the other end is connected to the first pad; and a low pass filter configured to be connected between the other end of the first filter and the first bias generator. ### Claim 2 (depends on 1) The microphone system according to claim 1, wherein the first filter unit is connected to the first pad and the first bias generator. ### Claim 3 (depends on 1) The microphone system according to claim 1, wherein the first filter filters the first noise, and the low pass filter filters the sensor bias voltage. ### Claim 4 (depends on 1) The microphone system according to claim 1, wherein the second filter unit includes a second filter including a capacitor in which one end is connected to an output terminal of the voltage buffer and the first filter unit and the other end is connected to the second pad and an input terminal of the voltage buffer. ### Claim 5 (depends on 1) The microphone system according to claim 1, wherein an input terminal of the voltage buffer is connected to the second pad and the second filter unit, and an output terminal of the voltage buffer is connected to the first filter unit, the second filter unit, and an output terminal of the read-out circuit. ### Claim 6 (depends on 1) The microphone system according to claim 1, wherein the voltage buffer comprises: a current source configured to provide a current of a predetermined magnitude in correspondence to an operating voltage; and a transistor configured to discharge the first noise or the second noise. ### Claim 7 (depends on 6) The microphone system according to claim 6, wherein the transistor includes a PMOS transistor. ### Claim 8 (depends on 6) The microphone system according to claim 6, wherein the transistor includes a gate connected to the second filter unit and the second pad, a drain connected to a ground terminal to which the first noise or the second noise is discharged, and a source connected to the current source. ### Claim 9 (depends on 1) The microphone system according to claim 1, wherein the voltage buffer includes a source follower having a voltage gain of 1 or less. ### Claim 10 (depends on 1) The microphone system according to claim 1, further comprising: a third filter unit configured to filter again the first noise filtered through the first filter unit or the second noise filtered through the second filter unit. ### Claim 11 (depends on 10) The microphone system according to claim 10, wherein the third filter unit comprises: a third filter in which one end is grounded and the other end is connected to the first filter unit and the second filter unit; a first resistor connected between the other end of the third filter and the voltage buffer; and a second resistor connected to the other end of the third filter and an output terminal of the read-out circuit. ### Claim 12 A microphone system comprising: a microphone sensor configured to generate sensing data by sensing a change in sound pressure through a sensor bias voltage; a read-out circuit configured to provide the sensor bias voltage for operating the microphone sensor, and receive and output the sensing data; a first pad configured to connect the microphone sensor and the read-out circuit to each other and allow the sensor bias voltage to pass therethrough; and a second pad configured to connect the microphone sensor and the read-out circuit to each other and allow the sensing data to pass therethrough, wherein the read-out circuit comprises: a separation buffer configured to separate a voltage environment of the first pad and the second pad; a first filter unit configured to filter the sensor bias voltage and filter first noise introduced from the first pad; a second filter unit configured to filter second noise introduced from the second pad; and a voltage buffer configured to amplify the sensing data; wherein the separation buffer discharges the filtered first noise, and the voltage buffer discharges the filtered second noise. ### Claim 13 (depends on 12) The microphone system according to claim 12, wherein an input terminal of the separation buffer is connected to an output terminal of the voltage buffer and the second filter unit, and an output terminal of the separation buffer is connected to the first filter unit. ### Claim 14 (depends on 12) The microphone system according to claim 12, wherein the first filter unit is connected to the first pad and an input terminal of the separation buffer. ### Claim 15 (depends on 12) The microphone system according to claim 12, wherein the second filter unit has one end connected to the separation buffer and an output terminal of the voltage buffer and the other end connected to the second pad and an input terminal of the voltage buffer.