Family of current/power-efficient high voltage linear regulator circuit architectures

• US 7,977,931 B2
• Filed: 03/18/2008
• Issued: 07/12/2011
• Est. Priority Date: 03/18/2008
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Wadhwa, Sameer
• Primary Examiner(s): Laxton; Gary L
• Application Number:
  US12/050,874
• Publication Number:
  US 20090237040A1
• Time in Patent Office: 1,211 Days
• Field of Search: 323/304, 323/311, 323/312, 323/313, 323/314, 323/315, 323/316
• US Class Current: 323/314
• CPC Class Codes: G05F 1/565 sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor G05F1/563 takes precedence
• CPC Class Codes: G09G 3/3466 based on interferometric effect

Abstract

Power efficient power supply regulator circuits are disclosed. The circuits are configured to modify their overhead current according to current load. This is particularly advantageous for use in display devices with widely varying current loads. Such displays include bi-stable displays, such as interferometric modulation displays, LCD displays, and DMD displays.

Claims

1. A voltage regulator circuit, comprising:

an input stage configured to receive an input bias current and generate a first output voltage;

an output stage configured to receive the first output voltage and an output bias current, and to supply an output current at a regulated output voltage based on the first output voltage and the output bias current; and

a generator configured to generate at least one of the input bias current and the output bias current,

wherein the generator is configured to at least one of;

receive the first output voltage to generate the input bias current, and

independent of the input stage, generate the output bias current based on the regulated output voltage.

2. The circuit of claim 1, wherein at least one of the input bias current and the output bias current is dependent at least in part on the output current.

3. The circuit of claim 1, further comprising a substantially fixed current source and a variable current source, wherein the circuit is configured to connect at least one of the fixed current source and the variable current source to a node based at least in part on the output current.

4. The circuit of claim 3, wherein the variable current source varies dependent at least in part on the difference between a voltage based on the regulated output voltage and a reference voltage.

5. The circuit of claim 1, further comprising a differential pair circuit configured to receive a tail current and a differential input voltage, wherein the tail current is dependent at least in part on the differential input voltage.

6. The circuit of claim 5, wherein the differential pair circuit produces a differential output current, and comprises first and second variable tail current generators, wherein the first and second tail current generators are configured to generate tail current based on opposite polarities of the differential output current.

7. The circuit of claim 1, wherein the input stage is configured to receive an input supply voltage and the output stage circuit is configured to receive an output supply voltage and the input supply voltage is different from the output supply voltage.

8. A method of controlling an output bias current in an output stage circuit of a voltage regulator circuit, the voltage regulator circuit configured to provide current substantially at a regulated output voltage, wherein the voltage regulator circuit comprises an input stage receiving an input bias current and generating a first output voltage, and an output stage receiving the first output voltage and the output bias current and generating the regulated output voltage based on the first output voltage, the method comprising:

sensing a difference between a voltage based on the output voltage and a reference voltage; and

independent of the first stage, generating the output bias current based on the difference.

9. The method of claim 8, further comprising increasing the bias current if the difference increases.

10. The method of claim 8, further comprising maintaining a fixed bias current if the difference decreases below a threshold.

11. The method of claim 8, further comprising producing a tail current amount for a differential pair of transistors in an amplifier circuit depending on the difference between the output voltage and the reference voltage.

12. A voltage regulator circuit, comprising:

an input stage circuit configured to receive an input bias current and to generate a first output voltage; and

an output stage circuit configured to receive the first output voltage and an output bias current, and to supply an output current at a regulated output voltage based on the first output voltage and the output bias current; and

a generator configured to generate at least one of the input bias current and the output bias current,

wherein the generator is configured to at least one of;

receive the first voltage output to generate the input bias current, and

independent of the input stage circuit, generate the output bias current based on a difference between a voltage based on the regulated output voltage and a reference voltage.

13. The circuit of claim 12, further comprising a differential pair circuit configured to receive a tail current and a differential input voltage, wherein the tail current is based at least in part on the difference.

14. The circuit of claim 13, wherein the differential pair circuit produces a differential output current, and comprises first and second variable tail current generators, wherein the first and second tail current generators are configured to generate tail current based on opposite polarities of the differential output current.

15. A display comprising:

a plurality of bi-stable display elements; and

a voltage regulator circuit, the voltage regulator circuit comprising;

an input stage circuit configured to receive an input bias current and generate a first output voltage;

an output stage circuit configured to receive the first output voltage and an output bias current, and to supply an output current at a regulated output voltage based on the first output voltage and the output bias current; and

a generator configured to generate at least one of the input bias current and the output bias current,

wherein the generator is configured to at least one of;

receive the first output voltage to generate the input bias current, and

independent of the input stage, generate the output bias current based on the regulated output voltage.

16. The display of claim 15, further comprising a substantially fixed current source and a variable current source, wherein the voltage regulator circuit is configured to connect at least one of the fixed current source and the variable current source to a node based at least in part on the output current.

17. The display of claim 16, wherein the variable current source varies based at least in part on the difference between a voltage based on the regulated output voltage and a reference voltage.

18. The display of claim 15, further comprising a differential pair circuit configured to receive a tail current and a differential input voltage, wherein the tail current is based at least in part on the differential input voltage.

19. The display of claim 15, wherein the input stage has an input supply voltage and the output stage has an output supply voltage and the input supply voltage is different from the output supply voltage.

20. A voltage regulator circuit, comprising:

first means for sensing a difference between a voltage based on the output voltage and a reference voltage;

means for generating an output current based on the difference sensed by the first sensing means; and

means for generating a bias current, comprising second means for sensing the difference between the voltage based on the output voltage and the reference voltage, wherein the bias current is generated based on the difference sensed by the second sensing means and is generated independent of the difference sensed by the first sensing means.

21. The circuit of claim 20, wherein the second sensing means comprises a voltage comparator.

22. The circuit of claim 20, wherein the generating means forms in part, an output stage.

23. The circuit of claim 20, wherein the bias current generating means comprises a bias current generator.

24. The circuit of claim 23, wherein the bias current generator comprises a substantially fixed current source and a variable current source, wherein the circuit is configured to connect at least one of the fixed current source and the variable current source to a node based at least in part on the output current.

25. The circuit of claim 23, wherein the bias current generator comprises a differential pair having a tail current and a differential input voltage, wherein the tail current is dependent at least in part on the differential input voltage.