BIASING CIRCUIT FOR MICROPHONE AND MICROPHONE INCLUDING THE SAME

• US 20160134967A1
• Filed: 07/30/2015
• Published: 05/12/2016
• Est. Priority Date: 11/11/2014
• Status: Abandoned Application

• Current Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Original Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Inventors: KWON, Soon Myung
• Application Number:
  US14/813,511
• Publication Number:
  US 20160134967A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04R 19/005 using semiconductor materials
• CPC Class Codes: H04R 19/04 Microphones H04R19/01 takes precedence
• CPC Class Codes: H04R 3/00 Circuits for transducers , loudspeakers or microphones

Abstract

A microphone in accordance with an exemplary embodiment of the present invention includes a biasing circuit to provide a variable bias voltage to a sensor. The biasing circuit includes: a regulator which receives a reference voltage and a control voltage to output a variable voltage; a digital to analog converter which receives a digital control signal to provide the control voltage to the regulator; and a charge pump which receives the variable voltage output from the regulator to output a variable voltage that is higher than the variable voltage.

Claims

1. A biasing circuit for providing a variable bias voltage to a sensor of a microphone, the biasing circuit comprising:

a regulator receiving a reference voltage and a control voltage and outputting a variable voltage corresponding to the received control voltage;

a digital to analog converter converting a received digital control signal to the control voltage transmitted to the regulator; and

a charge pump receiving the variable voltage output from the regulator and correspondingly outputting a variable voltage that is higher than the variable voltage.

2. The biasing circuit of claim 1, further comprising:

an oscillator generating a pulse signal; and

a level shifter receiving the pulse signal from the oscillator and the variable voltage from the regulator, and adjusting the pulse signal to a level of the variable voltage to provide the adjusted pulse signal to the charge pump.

3. The biasing circuit of claim 2, wherein the digital control signal comprises an 8-bit signal.

4. The biasing circuit of claim 2, wherein the regulator comprises a low-dropout (LDO) regulator.

5. The biasing circuit of claim 2, wherein the charge pump comprises a voltage tripler.

6. A microphone comprising:

a sensor; and

a biasing circuit to provide a variable bias voltage to the sensor,

wherein the biasing circuit comprises;

a low-dropout (LDO) regulator receiving a reference voltage and a control voltage and outputting a variable voltage corresponding to the received control voltage;

a digital to analog converter converts a received digital control signal to the control voltage transmitted to the LDO regulator;

an oscillator generating a pulse signal;

a level shifter receiving the pulse signal from the oscillator and the variable voltage from the regulator, and adjusting the pulse signal to a level of the variable voltage to output the adjusted pulse signal; and

a charge pump receiving the variable voltage output from the regulator and the adjusted pulse signal output from the level shifter and correspondingly outputting a variable voltage that is higher than the variable voltage.

7. The microphone of claim 6, wherein the sensor comprises a vibration membrane and a fixed electrode which have characteristics of a capacitor.

8. The microphone of claim 6, wherein the digital control signal comprises an 8-bit signal.

9. The microphone of claim 6, wherein the variable bias voltage is in a range of about 4.5 V to about 13.5 V.