# US 7,612,548 B2 · Low drop-out voltage regulator with high-performance linear and load regulation

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- Number: US 7,612,548 B2
- Document ID: US7612548B2
- Status: Granted
- Kind: B2
- Application number: 12/041,809
- Filed: 2008-03-04
- Published: 2009-01-08
- Granted: 2009-11-03
- Earliest claimed: 2007-07-03
- Assignees: Holtek Semiconductor Inc.
- Inventors: Ming-Hong Jian
- Web page: https://patentgrep.com/patent/US7612548B2

## CPC

- G05F 1/575: characterised by the feedback circuit
- G05F: SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES

## Abstract

A low drop-out voltage regulator with high-performance linear and load regulation, comprising: a reference voltage circuit, capable of providing a reference voltage; a differential amplifier; a power device, capable of driving a load resistor; a feedback circuit, disposed between the differential amplifier and the power device so that the differential amplifier outputs a correction voltage after the reference voltage and a feedback voltage across the feedback circuit; and a voltage buffer for frequency compensation, disposed between the differential amplifier and the power device, the voltage buffer comprising a complementary type buffer.

## Claims

### Claim 1

A low drop-out voltage regulator with high-performance linear and load regulation, comprising:
a reference voltage circuit, capable of providing a reference voltage;
a differential amplifier;
a power device, capable of driving a load resistor;
a feedback circuit, disposed between the differential amplifier and the power device so that the differential amplifier outputs a correction voltage after the reference voltage and a feedback voltage across the feedback circuit; and
a voltage buffer for frequency compensation, disposed between the differential amplifier and the power device, the voltage buffer comprising a complementary type buffer, wherein the complementary type buffer comprises a p-type buffer and an n-type buffer and each the p-type buffer and the n-type buffer is driven by a bias current provided by at least two current mirrors respectively.

### Claim 2 (depends on 1)

The low drop-out voltage regulator with high-performance linear and load regulation as recited in claim 1, wherein the differential amplifier is an error amplifier.

### Claim 3 (depends on 1)

The low drop-out voltage regulator with high-performance linear and load regulation as recited in claim 1, wherein one of each of at least two current mirrors is capable of mirroring 1/n the current from the power device to another power device.

### Claim 4

A low drop-out voltage regulator with high-performance linear and load regulation, comprising:
a reference voltage circuit, capable of providing a reference voltage;
a differential amplifier;
a power device, capable of driving a load resistor;
a feedback circuit, disposed between the differential amplifier and the power device so that the differential amplifier outputs a correction voltage after the reference voltage and a feedback voltage across the feedback circuit; and
a voltage buffer for frequency compensation, disposed between the differential amplifier and the power device, the voltage buffer comprising a complementary type buffer, wherein the complementary type buffer comprises a p-type buffer and an n-type buffer and each the p-type buffer and the n-type buffer is driven by a bias current provided by a current source respectively.

### Claim 5 (depends on 4)

The low drop-out voltage regulator with high-performance linear and load regulation as recited in claim 4, wherein the differential amplifier is an error amplifier.