Voltage supply circuit and microphone unit

• US 20060147062A1
• Filed: 01/05/2006
• Published: 07/06/2006
• Est. Priority Date: 01/06/2005
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: NEC Electronics Corporation (Renesas Electronics Corporation)
• Inventors: Ida, Masayuki, Kinoshita, Hiroshige, Niwa, Fumiyuki
• Granted Patent: US 7,864,970 B2
• Time in Patent Office: Days
• US Class Current: 381/113
• CPC Class Codes: H03F 1/0211 with control of the supply voltage or current
• CPC Class Codes: H03F 1/0261 with control of the polarisation voltage or current, e.g. gliding Class A
• CPC Class Codes: H03F 3/181 Low-frequency amplifiers, e.g. audio preamplifiers

Abstract

A voltage supply circuit includes a booster outputting a voltage boosted from a power supply voltage and an amplifier operating with a voltage output from the booster as a power supply and supplying a bias voltage to a sensor. An output voltage value of the booster that generates a power supply voltage of the amplifier is set according to a signal for specifying a sensitivity of the sensor.

Claims

1. A voltage supply circuit comprising:

a booster outputting a voltage boosted from a power supply voltage; and

an amplifier operating with a voltage output from the booster as a power supply and supplying a bias voltage to a sensor,

wherein an output voltage value of the booster is set according to a signal for specifying a sensitivity of the sensor.

2. The voltage supply circuit according to claim 1, wherein the booster comprises:

a power supply booster section boosting a power supply voltage, and

a voltage selector section selecting an output voltage value according to the signal for specifying a sensitivity of the sensor.

3. The voltage supply circuit according to claim 1, further comprising:

a feedback resistor for the amplifier.

4. The voltage supply circuit according to claim 2, further comprising:

a feedback resistor for the amplifier.

5. The voltage supply circuit according to claim 3, wherein a resistance value of the feedback resistor is determined according to the signal for specifying a sensitivity of the sensor.

6. The voltage supply circuit according to claim 4, wherein a resistance value of the feedback resistor is determined according to the signal for specifying a sensitivity of the sensor.

7. The voltage supply circuit according to claim 3, wherein the feedback resistor at least includes a first feedback resistor section and a second feedback resistor section and selects one from the first feedback resistor section and the second feedback resistor section as a feedback resistor for the amplifier according to the signal for specifying a sensitivity of the sensor.

8. The voltage supply circuit according to claim 4, wherein the feedback resistor at least includes a first feedback resistor section and a second feedback resistor section and selects one from the first feedback resistor section and the second feedback resistor section as a feedback resistor for the amplifier according to the signal for specifying a sensitivity of the sensor.

9. A microphone unit comprising:

a microphone receiving a bias voltage;

a booster outputting a voltage boosted from a power supply voltage; and

an amplifier operating with a voltage output from the booster as a power supply and supplying a bias voltage to the microphone,

wherein an output voltage value of the booster is set according to a signal for specifying a sensitivity of the microphone.

10. The microphone unit according to claim 9, wherein the booster comprises:

a power supply booster section boosting a power supply voltage, and

a voltage selector section selecting an output voltage value according to the signal for specifying a sensitivity of the microphone.

11. The microphone unit according to claim 9, further comprising:

a feedback resistor for the amplifier.

12. The microphone unit according to claim 10, further comprising:

a feedback resistor for the amplifier.

13. The microphone unit according to claim 11, wherein a resistance-value of the feedback resistor is determined according to the signal for specifying a sensitivity of the microphone.

14. The microphone unit according to claim 11, wherein the feedback resistor at least includes a first feedback resistor section and a second feedback resistor section and selects one from the first feedback resistor section and the second feedback resistor section as a feedback resistor for the amplifier according to the signal for specifying a sensitivity of the microphone.