BIAS ARRANGEMENT AND APPARATUS

• US 20100073079A1
• Filed: 11/07/2008
• Published: 03/25/2010
• Est. Priority Date: 09/24/2008
• Status: Abandoned Application

• Current Assignee: Sony Ericsson Mobile Communications AB (Sony Group Corp.)
• Original Assignee: Sony Ericsson Mobile Communications AB (Sony Group Corp.)
• Inventors: BIRCH, Magnus, ULLEN, Kaj, KORNER, Peter
• Application Number:
  US12/267,115
• Publication Number:
  US 20100073079A1
• Time in Patent Office: Days
• US Class Current: 327/540
• CPC Class Codes: H04B 15/00 Suppression or limitation of noise or interference by means associated with receiver H04B1/10
• CPC Class Codes: H04B 15/005 Reducing noise, e.g. humm, from the supply
• CPC Class Codes: H04B 15/02 Reducing interference from electric apparatus by means located at or near the interfering apparatus
• CPC Class Codes: H04B 2215/061 Reduction of burst noise, e.g. in TDMA systems
• CPC Class Codes: H04M 1/6058 involving the use of a headset accessory device connected to the portable telephone
• CPC Class Codes: H04R 2201/107 Monophonic and stereophonic headphones with microphone for two-way hands free communication
• CPC Class Codes: H04R 2499/11 Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's
• CPC Class Codes: H04R 3/00 Circuits for transducers , loudspeakers or microphones
• CPC Class Codes: H04R 3/007 Protection circuits for transducers

Abstract

A biasing arrangement for an electronic apparatus having an input device is disclosed. The biasing arrangement comprises a bias voltage generator arranged to provide a bias voltage; a bias resistor connected between the bias voltage generator and the input device; and a reference voltage point of the input device, wherein a voltage of the reference voltage point of the input device is provided to the bias voltage generator for controlling the bias voltage in relation to the voltage of the reference voltage point of the input device. An electronic apparatus is also disclosed.

Claims

1. A biasing arrangement for an electronic apparatus having an input device, the biasing arrangement comprising

a bias voltage generator arranged to provide a bias voltage;

a bias resistor connected between the bias voltage generator and the input device; and

a reference voltage point of the input device,

wherein a voltage of the reference voltage point of the input device is provided to the bias voltage generator for controlling the bias voltage in relation to the voltage of the reference voltage point of the input device.

2. The arrangement according to claim 1, wherein the reference voltage is a ground voltage.

3. The arrangement according to claim 1, wherein the bias voltage generator comprises

an amplifier having its output connected to the bias resistor, its positive input connected to the reference voltage point of the input device;

a feedback resistor connected between the output of the amplifier and a negative input of the amplifier; and

a current generator connected to the negative input of the amplifier and arranged to drive a current to a negative supply voltage.

4. The arrangement according to claim 3, comprising a signal output, wherein the biasing resistor and the input device are connected in series between the bias voltage generator output and a reference voltage, and the signal output is connected such that the alternating voltage over the biasing resistor is provided as an output signal.

5. The arrangement according to claim 1, wherein the input device comprises

a field effect transistor having its drain and source connected to terminals of the analog input arrangement;

and

a capacitive sensor connected between gate and source of the field effect transistor.

6. The arrangement according to claim 5, wherein the capacitive sensor is any of a condenser microphone, a microelectromechanical system sensor, and a liquid capacitive inclinometer.

7. The arrangement according to claim 4, further comprising a transistor connected between the biasing resistor and the input device with the collector of the transistor connected to the biasing resistor, the emitter of the transistor connected to the input device, and the base connected to a voltage for providing a bias point such that a signal swing of the output signal at the connection to the biasing resistor is provided.

8. The arrangement according to claim 4, wherein the signal output comprises connections to respective terminals of the biasing resistor, and at least one of the connections comprises a capacitor for alternating current coupling of the output signal.

9. An electronic apparatus having an input device, and a biasing arrangement, wherein the biasing arrangement comprises

a bias voltage generator arranged to provide a bias voltage;

a bias resistor connected between the bias voltage generator and the input device; and

a reference voltage point of the input device,

wherein a voltage of the reference voltage point of the input device is provided to the bias voltage generator for controlling the bias voltage in relation to the voltage of the reference voltage point of the input device.

10. The apparatus according to claim 9, wherein the reference voltage is a ground voltage.

11. The apparatus according to claim 9, wherein the bias voltage generator comprises

an amplifier having its output connected to the bias resistor, its positive input connected to the reference voltage point of the input device;

a feedback resistor connected between the output of the amplifier and a negative input of the amplifier; and

a current generator connected to the negative input of the amplifier and arranged to drive a current to a negative supply voltage.

12. The apparatus according to claim 11, comprising a signal output, wherein the biasing resistor and the input device are connected in series between the bias voltage generator output and a reference voltage, and the signal output is connected such that the alternating voltage over the biasing resistor is provided as an output signal.

13. The apparatus according to claim 9, wherein the input device comprises

a field effect transistor having its drain and source connected to terminals of the analog input arrangement;

and

a capacitive sensor connected between gate and source of the field effect transistor.

14. The apparatus according to claim 13, wherein the capacitive sensor is any of a condenser microphone, a microelectromechanical system sensor, and a liquid capacitive inclinometer.

15. The apparatus according to claim 12, further comprising a transistor connected between the biasing resistor and the input device with the collector of the transistor connected to the biasing resistor, the emitter of the transistor connected to the input device, and the base connected to a voltage for providing a bias point such that a signal swing of the output signal at the connection to the biasing resistor is provided.

16. The apparatus according to claim 12, wherein the signal output comprises connections to respective terminals of the biasing resistor, and at least one of the connections comprises a capacitor for alternating current coupling of the output signal.

17. The apparatus according to claim 9, wherein the input device of the apparatus comprises a microphone.

18. The apparatus according to claim 9, comprising a wired connection to the input device which comprises an antenna, wherein the antenna is connected to a radio receiver of the apparatus and separated from an audio input circuitry of the apparatus by a choke coil.

19. The apparatus according to claim 9, further comprising an output device, wherein the reference voltage point is used as reference voltage also for an output device.

20. The apparatus according to claim 19, wherein the output device of the apparatus comprises at least one speaker.

21. The apparatus according to claim 18, wherein the wired connection to the input device comprises a connector for detaching the input device from the apparatus.