Voltage adjusting circuit for amplifier circuit and method thereof

• US 9,306,501 B2
• Filed: 01/23/2014
• Issued: 04/05/2016
• Est. Priority Date: 01/25/2013
• Status: Expired due to Fees

• Current Assignee: Richtek Technology Corporation (MediaTek, Inc.)
• Original Assignee: Richtek Technology Corporation (MediaTek, Inc.)
• Inventors: Hsiao, Ming-Jun, Chang, Teng-Hung, Sun, Shao-Ming
• Primary Examiner(s): Nguyen, Khanh V
• Application Number:
  US14/162,406
• Publication Number:
  US 20140210432A1
• Time in Patent Office: 803 Days
• Field of Search: 330/279, 330/285, 330/297
• US Class Current: 1/1
• CPC Class Codes: H03F 1/0211 with control of the supply voltage or current
• CPC Class Codes: H03F 1/0233 by using a signal derived from the output signal, e.g. bootstrapping the voltage supply
• CPC Class Codes: H03F 1/0255 by using a signal derived from the output signal

Abstract

A voltage adjusting circuit includes a reference voltage generating circuit, a subtractor circuit, a threshold generating circuit and a comparator circuit. The voltage adjusting circuit may provide power supply signals to an amplifier circuit so that the amplifier circuit may provide an output signal to a load according to an input signal. The subtractor circuit generates a difference signal according to the output signal and the power supply signal. The comparator circuit compares the difference signal and a threshold signal generated by the threshold generating circuit for configuring the reference voltage generating circuit to adjust the signal value of the power supply signal.

Claims

1. A voltage adjusting circuit, configured to operably provide a first power signal and a second power signal to an amplifier circuit so that the amplifier circuit provides an output signal to a load according to an input signal, the first power signal and the second power signal, comprising:

a reference voltage generating circuit configured to operably configure the first power signal to be a first signal value and configure the second power signal to be a second signal value in a first time period;

a subtractor circuit coupled with the reference voltage generating circuit for generating a difference signal according to at least one of the first power signal and the second power signal and according to the output signal;

a threshold generating circuit configured to operably generate a first threshold signal; and

a comparator circuit coupled with the threshold generating circuit and the subtractor circuit for comparing the first threshold signal and the difference signal;

wherein when the difference signal is greater than the first threshold signal, the comparator circuit configures the reference voltage generating circuit to configure the first power signal to be a third signal value and configure the second power signal to be a fourth signal value in a second time period;

the third signal value is less than the first signal value; and

the fourth signal value is greater than or equal to the second signal value.

2. The voltage adjusting circuit of claim 1, further comprising:

a counter circuit coupled with the comparator circuit and the reference voltage generating circuit for calculating an accumulated number that the difference signal is less than the first threshold signal;

wherein when the accumulated number is greater than a predetermined accumulation number, the counter circuit configures the reference voltage generating circuit to configure the first power signal to be the third signal value and configure the second power signal in the second time period.

3. The voltage adjusting circuit of claim 1, wherein the threshold generating circuit further generates a second threshold signal and the comparator circuit compares the second threshold signal and the difference signal;

when the difference signal is less than the second threshold signal, the comparator circuit configures the reference voltage generating circuit to configure the first power signal to be a fifth signal value and configure the second power signal to be a sixth signal value in a third time period; and

the fifth signal value is greater than the first signal value and the sixth signal value is less than or equal to the second signal value.

4. The voltage adjusting circuit of claim 1, further comprising:

a load detection circuit coupled with the threshold generating circuit for detecting an impedance value of the load;

wherein when the impedance value of the load is less than a first predetermined impedance threshold, the load detection circuit configures the threshold generating circuit to provide the first threshold signal to the reference voltage generating circuit;

when the impedance of the load is greater than the first predetermined impedance threshold, the load detection circuit configures the threshold generating circuit to provide a third threshold signal to the reference voltage generating circuit; and

the third threshold signal is less than the first threshold signal.

5. The voltage adjusting circuit of claim 4, wherein the impedance of the load is less than a second predetermined impedance threshold, the load detection circuit configures the threshold generating circuit to provide a fifth threshold signal to the reference voltage generating circuit;

the first predetermined impedance threshold is greater than the second predetermined impedance threshold; and

the fifth threshold signal is greater than the first threshold signal.

6. The voltage adjusting circuit of claim 2, wherein

a load detection circuit coupled with the threshold generating circuit for detecting an impedance value of the load;

wherein when the impedance value of the load is less than a first predetermined impedance threshold, the load detection circuit configures the threshold generating circuit to provide the first threshold signal to the reference voltage generating circuit;

when the impedance of the load is greater than the first predetermined impedance threshold, the load detection circuit configures the threshold generating circuit to provide a third threshold signal to the reference voltage generating circuit; and

the third threshold signal is less than the first threshold signal.

7. The voltage adjusting circuit of claim 6, wherein the impedance of the load is less than a second predetermined impedance threshold, the load detection circuit configures the threshold generating circuit to provide a fifth threshold signal to the reference voltage generating circuit;

the first predetermined impedance threshold is greater than the second predetermined impedance threshold; and

the fifth threshold signal is greater than the first threshold signal.

8. The voltage adjusting circuit of claim 6, wherein when the impedance of the load is less than the first predetermined impedance threshold, the load detection circuit configures the threshold generating circuit to provide the second threshold signal to the reference voltage generating circuit;

when the impedance of the load is greater than the first predetermined impedance threshold, the load detection circuit configures the threshold generating circuit to provide a fourth threshold signal to the reference voltage generating circuit; and

the fourth threshold signal is less than the second threshold signal.

9. The voltage adjusting circuit of claim 6, wherein when the impedance of the load is less than a second predetermined impedance threshold, the load detection circuit configures the threshold generating circuit to provide a sixth threshold signal to the reference voltage generating circuit;

the first predetermined impedance threshold is greater than the second predetermined impedance threshold; and

the sixth threshold signal is greater than the second threshold signal.

10. A voltage adjusting method of an amplifier circuit for providing a first power signal and a second power signal to the amplifier circuit so that the amplifier circuit provides an output signal to a load according to an input signal, the first power signal and the second power signal, comprising:

in a first time period, configuring the first power signal to be a first signal value and configuring the second power signal to be a second signal value by utilizing a reference voltage generating circuit;

generating a difference signal by utilizing a subtractor circuit according to at least one of the first power signal and the second power signal and according to the output signal;

generating a first threshold signal by utilizing a threshold generating circuit;

comparing the first threshold signal and the difference signal by utilizing a comparator circuit; and

when the difference signal is greater than the first threshold signal, configuring the reference voltage generating circuit to configure the first power signal to be a third signal value and configure the second power signal to be a fourth signal value in a second time period;

wherein the third signal value is less than the first signal value and the fourth signal value is greater than or equal to the second signal value.

11. The voltage adjusting method of claim 10, further comprising:

calculating an accumulated number that the difference signal is less than the first threshold signal by utilizing a counter circuit;

when the accumulated number is greater than a predetermined accumulation number, configuring the reference voltage generating circuit to configure the first power signal to be the third signal value and configure the second power signal to be the fourth signal value in the second time period.

12. The voltage adjusting method of claim 10, further comprising:

generating a second threshold signal by utilizing the threshold generating circuit;

comparing the second threshold signal and the difference signal by utilizing the comparator circuit; and

when the difference signal is less than the second threshold signal, configuring the reference voltage generating circuit to configure the first power signal to be a fifth signal value and configure the second power signal to be a sixth signal value in a third time period;

wherein the fifth signal value is greater than the first signal value and the sixth signal value is less than or equal to the second signal value.

13. The voltage adjusting method of claim 10, further comprising:

detecting an impedance value of the load by utilizing a load detection circuit;

when the impedance value of the load is less than a first predetermined impedance threshold, configuring the threshold generating circuit to provide the first threshold signal to the reference voltage generating circuit; and

when the impedance of the load is greater than the first predetermined impedance threshold, configuring the threshold generating circuit to provide a third threshold signal to the reference voltage generating circuit;

wherein the third threshold signal is less than the first threshold signal.

14. The voltage adjusting method of claim 13, further comprising:

when the impedance of the load is less than a second predetermined impedance threshold, configuring the threshold generating circuit to provide a fifth threshold signal to the reference voltage generating circuit;

wherein the first predetermined impedance threshold is greater than the second predetermined impedance threshold, and the fifth threshold signal is greater than the first threshold signal.

15. The voltage adjusting method of claim 11, further comprising:

detecting an impedance value of the load by utilizing a load detection circuit;

when the impedance value of the load is less than a first predetermined impedance threshold, configuring the threshold generating circuit to provide the first threshold signal to the reference voltage generating circuit; and

when the impedance of the load is greater than the first predetermined impedance threshold, configuring the threshold generating circuit to provide a third threshold signal to the reference voltage generating circuit;

wherein the third threshold signal is less than the first threshold signal.

16. The voltage adjusting method of claim 15, further comprising:

when the impedance of the load is less than a second predetermined impedance threshold, configuring the threshold generating circuit to provide a fifth threshold signal to the reference voltage generating circuit;

wherein the first predetermined impedance threshold is greater than the second predetermined impedance threshold, and the fifth threshold signal is greater than the first threshold signal.

17. The voltage adjusting method of claim 15, further comprising:

when the impedance of the load is less than the first predetermined impedance threshold, configuring the threshold generating circuit to provide the second threshold signal to the reference voltage generating circuit; and

when the impedance of the load is greater than the first predetermined impedance threshold, configuring the threshold generating circuit to provide a fourth threshold signal to the reference voltage generating circuit;

wherein the fourth threshold signal is less than the second threshold signal.

18. The voltage adjusting method of claim 15, further comprising:

when the impedance of the load is less than a second predetermined impedance threshold, configuring the threshold generating circuit to provide a sixth threshold signal to the reference voltage generating circuit;

wherein the first predetermined impedance threshold is greater than the second predetermined impedance threshold and the sixth threshold signal is greater than the second threshold signal.

19. A voltage adjusting circuit, configured to operably provide a first power signal and a second power signal to an amplifier circuit so that the amplifier circuit provides an output signal to a load according to an input signal, the first power signal and the second power signal, comprising:

a reference voltage generating circuit configured to operably configure the first power signal to be a first signal value and configure the second power signal to be a second signal value in a first time period;

a subtractor circuit coupled with the reference voltage generating circuit for generating a difference signal according to at least one of the first power signal and the second power signal and according to the output signal;

a threshold generating circuit configured to operably generate a first threshold signal; and

a comparator circuit coupled with the threshold generating circuit and the subtractor circuit for comparing the first threshold signal and the difference signal;

wherein when the difference signal is greater than the first threshold signal, the comparator circuit configures the reference voltage generating circuit to configure the first power signal to be a third signal value and configure the second power signal to be a fourth signal value in a second time period;

the third signal value is less than or equal to the first signal value; and

the fourth signal value is greater than the second signal value.

20. The voltage adjusting circuit of claim 19, wherein the threshold generating circuit further generates a second threshold signal and the comparator circuit compares the second threshold signal and the difference signal;

when the difference signal is less than the second threshold signal, the comparator circuit configures the reference voltage generating circuit to configure the first power signal to be a fifth signal value and configure the second power signal to be a sixth signal value in a third time period; and

the fifth signal value is greater than or equal to the first signal value and the sixth signal value is less than or equal to the second signal value.