Semiconductor apparatus for power supply control and output voltage variable power supply apparatus

Patent metadata

Field	Value
Publication number	US-10831222-B2
Application number	US-201916352765-A
Country	US
Kind code	B2
Filing date	Mar 13, 2019
Priority date	Apr 3, 2018
Publication date	Nov 10, 2020
Grant date	Nov 10, 2020

Abstract

A semiconductor apparatus for power supply control includes the following. A voltage control transistor is connected between a voltage input terminal and an output terminal. A control circuit controls the voltage control transistor according to an output feedback voltage. A first external terminal is supplied with an output control signal to control output voltage is input. The control circuit further includes the following. A first error amplifier outputs a voltage according to an electric potential difference between a voltage divided by a first voltage dividing circuit which divides the output voltage of the output terminal and a predetermined reference voltage. An output changing circuit displaces the reference voltage input in the first error amplifier or the voltage divided by the first voltage dividing circuit according to a voltage input in the first external terminal to change the output voltage to a voltage according to the output control signal.

First claim

What is claimed is:

1. A semiconductor apparatus for power supply control comprising:
a voltage control transistor connected between a voltage input terminal in which DC voltage is input and an output terminal;
a control circuit which controls the voltage control transistor according to an output feedback voltage; and
a first external terminal in which an output control signal supplied from outside to control output voltage is input,
wherein, the control circuit further includes:
a first error amplifier which outputs a voltage according to an electric potential difference between a voltage divided by a first voltage dividing circuit which divides the output voltage of the output terminal and a predetermined reference voltage; and
an output changing circuit which displaces the reference voltage input in the first error amplifier or the voltage divided by the first voltage dividing circuit according to a voltage input in the first external terminal to change the output voltage to a voltage according to the output control signal.

2. The semiconductor apparatus for power supply control according to claim 1 , wherein, the output voltage changing circuit includes,
a second voltage dividing circuit which divides the voltage input in the first external terminal,
a first transistor and a first resistor element connected in series between a node from which the voltage divided by the first voltage dividing circuit is taken out and a constant potential point, and
a second error amplifier which outputs voltage according to an electric potential difference between the voltage divided by the second voltage dividing circuit and the voltage converted by current-voltage conversion by the first resistor element,
wherein, the output of the second error amplifier is applied to a control terminal of the first transistor.

3. The semiconductor apparatus for power supply control according to claim 1 , wherein, the output voltage changing circuit includes,
a third voltage dividing circuit which divides the reference voltage,
a second transistor and a second resistor element connected in series between a node from which voltage divided by the third voltage dividing circuit is taken out and a constant potential point, and
a third error amplifier which outputs voltage according to an electric potential difference between a voltage input in the first external terminal and the voltage converted by current-voltage conversion by the second resistor element,
wherein the output of the third error amplifier is applied to the control terminal of the second transistor.

4. The semiconductor apparatus for power supply control according to claim 1 , wherein the output voltage changing circuit includes,
a fourth error amplifier in which voltage input in the first external terminal is input,
a third transistor in which output of the second error amplifier is applied to the control terminal,
a current mirror circuit which is connected to the voltage input terminal and which transfers an electric current flowing in the third transistor, and
a third resistor element connected in series with the third transistor,
wherein, the fourth error amplifier outputs voltage according to an electric potential difference between the voltage input in the first external terminal and the voltage converted by current-voltage conversion by the third resistor element to the control terminal of the third transistor, flows an electric current according to the electric potential difference in the third transistor, and pulls out from or flows in the node from which the voltage divided by the first voltage dividing circuit is taken out the electric current transferred in the current mirror circuit.

5. The semiconductor apparatus for power supply control according to claim 1 , further comprising,
a reference voltage source which generates the reference voltage;
a bias circuit which generates an operation electric current supplied to the reference voltage source and the first error amplifier; and
a second external terminal in which a control signal supplied from outside is input to stop an operation of the power supply apparatus,
wherein the bias circuit stops the supply of the operation electric current to the reference voltage source and the first error amplifier according to the control signal input in the second external terminal.

6. An output voltage variable power supply apparatus comprising:
the semiconductor apparatus for power supply control according to claim 1 ; and
a control apparatus which outputs a signal input to the first external terminal or the first external terminal and the second external terminal,
wherein, the output voltage changes according to the signal input from the control apparatus to the first external terminal.

7. The output voltage variable power supply apparatus according to claim 6 , wherein a load connected to the output terminal of the semiconductor apparatus for power supply control is a DC motor.

Assignees

• Maki Shinichiro
• Takano Yoichi
• Yokoyama Katsuhiro
• Mitsumi Electric Co Ltd

Inventors

• Maki Shinichiro
• Takano Yoichi
• Yokoyama Katsuhiro

Classifications

• G05F1/59 Primary

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

• G05F1/575

  characterised by the feedback circuit · CPC title

• G05F1/462 Primary

  as a function of the requirements of the load, e.g. delay, temperature, specific voltage/current characteristic · CPC title

• G05F3/26

  Current mirrors · CPC title

• H02P7/285

  controlling armature supply only · CPC title