Linear power supply circuit

Patent metadata

Field	Value
Publication number	US-2016299518-A1
Application number	US-201615092061-A
Country	US
Kind code	A1
Filing date	Apr 6, 2016
Priority date	Apr 10, 2015
Publication date	Oct 13, 2016
Grant date	—

Abstract

A linear power supply circuit includes a first output transistor of a P-channel type or pnp type which is connected between an input terminal to which an input voltage is input and an output terminal from which an output voltage is output; a first differential amplifier configured to amplify a difference between the output voltage or a feedback voltage according to the output voltage and a predetermined first reference voltage and output a first amplification voltage; a second differential amplifier configured to amplify a difference between the input voltage or a first monitor voltage according to the input voltage and the output voltage or a second monitor voltage according to the output voltage and output a second amplification voltage; and a first driver configured to generate a control voltage of the first output transistor according to the first amplification voltage and the second amplification voltage.

First claim

What is claimed is:

1 . A linear power supply circuit comprising:
a first output transistor of a P-channel type or pnp type which is connected between an input terminal to which an input voltage is input and an output terminal from which an output voltage is output; a first differential amplifier configured to amplify a difference between the output voltage or a feedback voltage according to the output voltage and a predetermined first reference voltage and output a first amplification voltage; a second differential amplifier configured to amplify a difference between the input voltage or a first monitor voltage according to the input voltage and the output voltage or a second monitor voltage according to the output voltage and output a second amplification voltage; and a first driver configured to generate a control voltage of the first output transistor according to the first amplification voltage and the second amplification voltage.

2 . The linear power supply circuit of claim 1 , further comprising:
a first voltage divider configured to divide the input voltage according to a first voltage division ratio and generate the first monitor voltage; and a second voltage divider configured to divide the output voltage according to a second voltage division ratio and generate the second monitor voltage.

3 . The linear power supply circuit of claim 2 , wherein the first voltage division ratio is designed to be equal to or lower than the second voltage division ratio.

4 . The linear power supply circuit of claim 1 , wherein the first driver includes:
a first transistor of a pnp type or P-channel type, which is connected between the input terminal and a control terminal of the first output transistor, the first transistor having a conductance being changed by the first amplification voltage; a second transistor of a pnp type or P-channel type, which is connected between the input terminal and the control terminal of the first output transistor, the second transistor having a conductance being changed by the second amplification voltage; a current source connected between the control terminal of the first output transistor and a ground terminal; and a first resistor connected between the input terminal and the control terminal of the first output transistor.

5 . The linear power supply circuit of claim 1 , further comprising:
a second output transistor of an N-channel type or npn type which is connected between the input terminal and the output terminal; a third differential amplifier configured to amplify a difference between the output voltage or the feedback voltage and a predetermined second reference voltage higher than the first reference voltage and output a third amplification voltage; and a second driver configured to generate a control voltage of the second output transistor according to the third amplification voltage.

6 . The linear power supply circuit of claim 5 , wherein the second driver includes:
a third transistor of an N-channel type or npn type, which is connected between a control terminal of the second output transistor and a ground terminal, the third transistor having a conductance being changed by the third amplification voltage; and a second resistor connected between the input terminal and the control terminal of the second output transistor.

7 . A linear power supply circuit comprising:
a first output transistor of a P-channel type or pnp type which is connected between an input terminal to which an input voltage is input and an output terminal from which an output voltage is output; a second output transistor of an N-channel type or npn type which is connected between the input terminal and the output terminal; a first differential amplifier configured to amplify a difference between the output voltage or a feedback voltage according to the output voltage and a predetermined first reference voltage and output a first amplification voltage; a second differential amplifier configured to amplify a difference between the output voltage or the feedback voltage and a predetermined second reference voltage higher than the first reference voltage and output a second amplification voltage; a first driver configured to generate a control voltage of the first output transistor according to the first amplification voltage; and a second driver configured to generate a control voltage of the second output transistor according to the second amplification voltage.

8 . The linear power supply circuit of claim 7 , wherein the first driver includes:
a first transistor of a pnp type or P-channel type, which is connected between the input terminal and a control terminal of the first output transistor, the first transistor having a conductance being changed by the first amplification voltage; a current source connected between the control terminal of the first output transistor and a ground terminal; and a first resistor connected between the input terminal and the control terminal of the first output transistor.

9 . The linear power supply circuit of claim 7 , wherein the second driver includes:
a second transistor of an N-channel type or npn type, which is connected between a control terminal of the second output transistor and a ground terminal, the second transistor having a conductance being changed by the second amplification voltage; and a second resistor connected between the input terminal and the control terminal of the second output transistor.

10 . The linear power supply circuit of claim 7 , further comprising:
a reference voltage generator configured to divide a predetermined reference voltage and generate each of the first reference voltage and the second reference voltage.

Assignees

• Rohm Co Ltd

Inventors

• Iwata Kotaro
• Inoue Hiroki
• Jin Zhencheng

Classifications

• G05F1/468 Primary

  characterised by reference voltage circuitry, e.g. soft start, remote shutdown · CPC title

• G05F1/59

  including plural semiconductor devices as final control devices for a single load · CPC title