Gain adjustment device and method thereof

• US 8,063,704 B2
• Filed: 08/25/2009
• Issued: 11/22/2011
• Est. Priority Date: 08/25/2008
• Status: Active Grant

• Current Assignee: Realtek Semiconductor Corp.
• Original Assignee: Realtek Semiconductor Corp.
• Inventors: Yang, Chung-Ting, Wu, Po-Chiang
• Primary Examiner(s): Mottola; Steven J
• Application Number:
  US12/547,148
• Publication Number:
  US 20100045374A1
• Time in Patent Office: 819 Days
• Field of Search: 330/129, 330/279, 381/120
• US Class Current: 330/279
• CPC Class Codes: H03G 1/0088 using discontinuously variable devices, e.g. switch-operated
• CPC Class Codes: H03G 3/3026 the gain being discontinuously variable, e.g. controlled by switching

Abstract

A gain adjustment device and a method thereof are provided. The device includes a first processing module, a gain adjustment circuit, a second processing module, and a gain control module. The first processing module receives an input signal and generates a first signal. An operating voltage of the first processing module is a first voltage. The gain adjustment circuit receives the first signal and adjusts a gain of the first signal according to a gain control signal to output a third signal. The second processing module receives the third signal and generates a second signal. An operating voltage of the second processing module is a second voltage. The gain control module generates the gain control signal according to the first voltage and the second voltage.

Claims

1. A gain adjustment device, comprising:

a first processing module, for receiving an input signal to generate a first signal, wherein an operating voltage of the first processing module is a first voltage;

a gain adjustment circuit, for receiving the first signal, and adjusting a gain of the first signal according to a gain control signal to output a third signal;

a second processing module, for receiving the third signal to generate a second signal, wherein an operating voltage of the second processing module is a second voltage; and

a gain control module, for generating the gain control signal according to the first voltage and the second voltage.

2. The gain adjustment device according to claim 1, wherein the gain control module further comprises:

a voltage detection module generating a detection signal according to values of the first voltage and the second voltage; and

a control module, coupled to the voltage detection module, receiving the detection signal, and generating the gain control signal according to the detection signal.

3. The gain adjustment device according to claim 1, wherein the gain comprising a direct current voltage gain and an alternating current (AC) voltage gain.

4. The gain adjustment device according to claim 3, further comprising:

a zero crossing detector (ZCD) detecting a zero-crossing point of the first signal, and adjusting the alternating current (AC) voltage gain.

5. The gain adjustment device according to claim 1, wherein the first processing module is an audio codec, and the first signal is an audio signal generated by the audio codec.

6. The gain adjustment device according to claim 1, wherein the second processing module is an audio amplifier, and the second signal is an amplified audio signal generated by the audio amplifier.

7. A gain adjustment method, comprising:

receiving a first signal from a first processing module, wherein an operating voltage of the first processing module is a first voltage;

adjusting a gain of the first signal according to a gain control signal to output a third signal;

processing the third signal by a second processing module to generate a second signal, wherein an operating voltage of the second processing module is a second voltage; and

generating the gain control signal according to the first voltage and the second voltage.

8. The method according to claim 7, wherein the step of generating the gain control signal further comprises:

generating a detection signal according to values of the first voltage and the second voltage; and

generating the gain control signal according to the detection signal.

9. The method according to claim 7, further comprising:

detecting a zero-crossing point of the first signal, and adjusting an alternating current (AC) voltage gain of the gain.

10. An output device, comprising:

a first signal processing module generating a first signal;

a second signal processing module processing a third signal to generate a second signal;

an amplifier module, having an adjustable voltage gain, coupled between the first signal processing module and the second signal processing module, and converting the first signal into the third signal;

a gain adjustment module, receiving a first voltage and a second voltage, and generating a gain control signal according to the first voltage and the second voltage to adjust the adjustable voltage gain; and

a zero crossing detector (ZCD), for detecting a zero-crossing point of the first signal, and adjusting an alternating current (AC) voltage gain of the adjustable voltage gain.

11. The output device according to claim 10, wherein the gain adjustment module further comprises:

a voltage adjustment circuit, receiving the first voltage and the second voltage, and generating a first divided voltage corresponding to the first voltage and a second divided voltage corresponding to the second voltage according to an adjustment signal;

a voltage detection module, coupled to the voltage adjustment circuit, receiving the first divided voltage and the second divided voltage, and generating a detection signal according to values of the first divided voltage and the second divided voltage; and

a control module, coupled to the voltage detection module, receiving the detection signal, and generating the gain control signal according to the detection signal.

12. The output device according to claim 11, wherein the voltage detection module further comprises:

a comparator, receiving the first divided voltage and the second divided voltage, and generating a difference between the first divided voltage and the second divided voltage; and

a determining unit, coupled to the comparator, receiving the difference, and determining a value of the difference, so as to generate the detection signal according to the difference and a preset value,

wherein when the difference is larger than the preset value, the detection signal is used for notifying the control module to generate the adjustment signal, and when the difference is smaller than the preset value, the detection signal is used for notifying the control module to generate the gain control signal.

13. The output device according to claim 10, wherein the gain comprising a direct current voltage gain and an alternating current voltage gain.

14. The output device according to claim 10, wherein the first signal processing module is an audio codec, the first signal is an audio signal generated by the audio codec, and the first voltage is a voltage provided to the audio codec.

15. The output device according to claim 10, wherein the second signal processing module is an audio amplifier, the second signal is an amplified audio signal generated by the audio amplifier, and the second voltage is a voltage provided to the audio amplifier.

16. An output device, comprising:

a first signal processing module generating a first signal;

a second signal processing module processing a third signal to generate a second signal;

an amplifier module, having an adjustable voltage gain, coupled between the first signal processing module and the second signal processing module, and converting the first signal into the third signal;

a gain adjustment module, receiving a first voltage and a second voltage, and generating a gain control signal according to the first voltage and the second voltage to adjust the adjustable voltage gain; and

a voltage adjustment circuit, receiving the first voltage and the second voltage, and generating a first divided voltage corresponding to the first voltage and a second divided voltage corresponding to the second voltage according to an adjustment signal.

17. The output device according to claim 16, further comprising a voltage detection module, coupled to the voltage adjustment circuit, receiving the first divided voltage and the second divided voltage, and generating a detection signal according to values of the first divided voltage and the second divided voltage.

18. The output device according to claim 17, further comprising a control module, coupled to the voltage detection module, receiving the detection signal, and generating the gain control signal according to the detection signal.