Linear power supply circuit

Patent metadata

Field	Value
Publication number	US-2021382510-A1
Application number	US-201917283389-A
Country	US
Kind code	A1
Filing date	Oct 21, 2019
Priority date	Oct 31, 2018
Publication date	Dec 9, 2021
Grant date	—

Abstract

A linear power supply circuit according to the present invention is provided with: an output transistor provided between an input end to which an input voltage is applied and an output end to which an output voltage is applied; a driver for driving the output transistor; and a feedback unit for feeding, back to the driver, information about an output electrical current that is output from the output end. The driver drives the output transistor on the basis of the difference between a voltage based on the output voltage and a reference voltage, as well as the information.

First claim

1 . A linear power supply circuit, comprising:
an output transistor provided between an input terminal, to which an input voltage is applied, and an output terminal, to which an output voltage is applied; a driver configured to drive the output transistor; and a feedback circuit configured to feed, back to the driver, information on an output current fed out via the output terminal, wherein the driver is configured to drive the output transistor based on
a difference between a voltage based on the output voltage and a reference voltage, and
the information.

2 . The linear power supply circuit according to claim 1 ,
wherein the driver includes a differential amplifier configured to output a voltage commensurate with the difference between the voltage based on the output voltage and the reference voltage, and the feedback circuit is configured to feed the information back to a first predetermined point across a first path between an output of the differential amplifier and the output terminal.

3 . The linear power supply circuit according to claim 2 ,
wherein the driver further includes:
a converter configured to convert a voltage based on the output of the differential amplifier into a current and output the current; and
a current amplifier configured to perform current amplification on an output of the converter, and
the feedback circuit is configured to feed the information back to the current amplifier.

4 . The linear power supply circuit according to claim 3 ,
wherein the feedback circuit is configured to acquire the information from a second predetermined point across a second path between an input of the current amplifier and the output terminal, and the second predetermined point is located closer, than the first predetermined point, to the output terminal.

5 . The linear power supply circuit according to claim 4 ,
wherein the current amplifier includes a plurality of current-sink current mirror circuits and a plurality of current-source current mirror circuits, an input of one of the current-sink current mirror circuits is the first predetermined point, the feedback circuit is configured to draw a current commensurate with the information from the first predetermined point, and a maximum value of a sum current of the current drawn from the first predetermined point by the feedback circuit and a current drawn from the first predetermined point by the current-sink current mirror circuit of which the input is the first predetermined point does not depend on the output of the converter.

6 . The linear power supply circuit according to claim 4 , further comprising a phase compensation circuit configured to perform phase compensation,
wherein the phase compensation circuit is located elsewhere than between the first and second predetermined points.

7 . The linear power supply circuit according to claim 2 ,
wherein the driver further includes a capacitor of which one terminal is fed with the output of the differential amplifier and of which another terminal is fed with a ground potential, and a supply voltage for the differential amplifier is the voltage based on the output voltage.

8 . The linear power supply circuit according to claim 3 ,
wherein the driver further includes a capacitor of which one terminal is fed with the output of the differential amplifier and of which another terminal is fed with a ground potential, a supply voltage for the differential amplifier is the voltage based on the output voltage, a supply voltage for the converter is the voltage based on the output voltage, and a supply voltage for the current amplifier is a constant voltage.

9 . The linear power supply circuit according to claim 3 ,
wherein the driver further includes a capacitor of which one terminal is fed with the output of the differential amplifier and of which another terminal is fed with the voltage based on the output voltage, and either
a supply voltage for the differential amplifier is a first constant voltage and a supply voltage for the current amplifier is a second constant voltage or
the supply voltage for the differential amplifier and the supply voltage for the current amplifier are the input voltage.

10 . The linear power supply circuit according to claim 8 , wherein
a withstand voltage of the differential amplifier is lower than a withstand voltage of the current amplifier.

11 . The linear power supply circuit according to claim 8 , wherein
a gain of the differential amplifier is lower than a gain of the current amplifier.

12 . The linear power supply circuit according to claim 1 , wherein
an output stage of the driver is of a push-pull type.

13 . The linear power supply circuit according to claim 1 , wherein
the feedback circuit is configured to negatively feed back to the driver the information in a form of a current.

14 . A vehicle comprising the linear power supply circuit according to claim 1 .

Assignees

• Rohm Co Ltd

Inventors

• Takobe Isao
• Yamaguchi Yuhei
• Watanabe Yukihiro
• Hashiguchi Shingo

Classifications

• G05F3/26

  Current mirrors · CPC title

• G05F1/56 Primary

  using semiconductor devices in series with the load as final control devices (G05F1/461 takes precedence) · CPC title

• B60R16/03

  for supply of electrical power to vehicle subsystems {or for (circuit arrangements for charging batteries H02J7/00)} · CPC title

• H03F3/45071

  with semiconductor devices only · CPC title

• G05F1/575 Primary

  characterised by the feedback circuit · CPC title