POWER REGULATOR

• US 20100066326A1
• Filed: 09/08/2009
• Published: 03/18/2010
• Est. Priority Date: 09/16/2008
• Status: Abandoned Application

• Current Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Original Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Inventors: HUANG, Hao-Chen
• Application Number:
  US12/555,108
• Publication Number:
  US 20100066326A1
• Time in Patent Office: Days
• US Class Current: 323/282
• CPC Class Codes: G05F 1/56 using semiconductor devices in series with the load as final control devices G05F1/461 takes precedence

Abstract

A power regulator for converting an input voltage to an output voltage includes a pass device and an error amplifier. The pass device receives the input voltage and provides the output voltage at an output terminal of the power regulator. The error amplifier coupled to the pass device includes a transistor. The transistor receives a reference signal and a feedback signal indicative of the output voltage, compares the feedback signal to the reference signal, and generates a control signal according to a result of the comparison to drive the pass device.

Claims

1. A power regulator for converting an input voltage to an output voltage, said power regulator comprising:

a pass device operable for receiving said input voltage and providing said output voltage at an output terminal of said power regulator; and

an error amplifier coupled to said pass device, said error amplifier comprising;

a first transistor operable for receiving a reference signal and a feedback signal indicative of said output voltage, for comparing said feedback signal to said reference signal, and for generating a first control signal according to a result of said comparison to drive said pass device.

2. The power regulator of claim 1, wherein said error amplifier further comprises a driver coupled to said first transistor and said pass device, and operable for generating a second control signal to control a conductance of said pass device in response to said first control signal.

3. The power regulator of claim 2, wherein said pass device comprises a second transistor, and wherein said driver generates said second control signal to control a gate-source voltage of said second transistor.

4. The power regulator of claim 2, wherein said driver comprises:

a second transistor coupled to said first transistor and operable for receiving said first control signal; and

a resistor coupled to said second transistor and said pass device and for providing said second control signal to control said conductance of said pass device.

5. The power regulator of claim 1, wherein said error amplifier further comprises a second transistor coupled to said first transistor and operable for maintaining said output voltage at a predetermined level if the temperature of said power regulator varies.

6. The power regulator of claim 5, wherein a collector-to-emitter voltage of said second transistor varies according to the temperature of said power regulator to compensate a variation of a base-to-emitter voltage of said first transistor.

7. The power regulator of claim 1, wherein said reference signal and said feedback signal are provided to a base and an emitter of said first transistor respectively, and wherein said first control signal is generated at a collector of said first transistor.

8. The power regulator of claim 1, wherein a collector current of said first transistor varies according to a difference between said feedback signal and said reference signal, and wherein said collector current is configured to control a conductance of said pass device.

9. An electronic system comprising:

a load;

a processor coupled to said load and operable for controlling said load; and

a power regulator coupled to said load and operable for powering said load by an output voltage, said power regulator comprising;

a pass device operable for receiving an input voltage and providing said output voltage; and

a first transistor operable for receiving a reference signal and a feedback signal indicative of said output voltage, for comparing said feedback signal to said reference signal, and for generating a first control signal according to a result of said comparison to drive said pass device.

10. The electronic system of claim 9, wherein said power regulator further comprises a driver coupled to said first transistor and said pass device and operable for generating a second control signal to control a conductance of said pass device in response to said first control signal.

11. The electronic system of claim 10, wherein said pass device comprises a second transistor, and wherein said driver generates said second control signal to control a gate-source voltage of said second transistor.

12. The electronic system of claim 9, wherein said power regulator further comprises:

a second transistor coupled to said first transistor and operable for maintaining said output voltage at a predetermined level if the temperature of said power regulator varies.

13. The electronic system of claim 12, wherein a collector-to-emitter voltage of said second transistor varies according to the temperature of said power regulator to compensate a variation of a base-to-emitter voltage of said first transistor.

14. The electronic system of claim 9, wherein said reference signal and said feedback signal are provided to a base and an emitter of said first transistor respectively, and wherein said first control signal is generated at a collector of said first transistor.

15. The electronic system of claim 9, wherein a collector current of said first transistor varies according to a difference between said feedback signal and said reference signal, and wherein said collector current is configured to control a conductance of said pass device.

16. A method for converting an input voltage to an output voltage, said method comprising:

receiving a first signal indicative of a reference signal by a transistor;

receiving a second signal indicative of said output voltage by said transistor;

sensing a difference between said first signal and said second signal by said transistor;

generating a first control signal based on said difference by said transistor; and

adjusting said output voltage according to said first control signal.

17. The method of claim 16, further comprising:

providing said first signal and said second signal to a base and an emitter of said transistor respectively; and

generating said first control signal at a collector of said transistor.

18. The method of claim 16, further comprising:

varying a collector current of said transistor according to a difference between said feedback signal and said reference signal, and

controlling a conductance of a pass device according to said collector current.

19. The method of claim 16, further comprising:

receiving said input voltage by a pass device;

generating a second control signal to control a conductance of said pass device in response to said first control signal; and

providing said output voltage by said pass device.

20. The method of claim 16, further comprising:

maintaining said output voltage at a predetermined level if the temperature of a regulator that converts said input voltage to said output voltage varies.