Current-limiting protection circuit and electronic device

Patent metadata

Field	Value
Publication number	US-10411464-B2
Application number	US-201515545847-A
Country	US
Kind code	B2
Filing date	Jan 22, 2015
Priority date	Jan 22, 2015
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

Abstract

A current-limiting protection circuit and an electronic device are provided. The current-limiting protection circuit includes a power supply chip and a current-limiting circuit that is electrically connected to the power supply chip. The current-limiting circuit is configured to detect a charging current, and output a feedback voltage to the power supply chip. The power supply chip is configured to when the feedback voltage is greater than a second reference voltage, reduce an output voltage until the charging current reaches a preset value, where the second reference voltage is a preset internal voltage of the power supply chip.

First claim

What is claimed is:

1. A current-limiting protection circuit, comprising:
a current-limiting circuit; and
a power supply chip coupled to the current-limiting circuit, wherein the power supply chip comprises an output pin and a feedback pin,
wherein the current-limiting circuit comprises:
a current sampling resistor;
at least one voltage conversion resistor;
a first operational amplifier;
a triode;
a first voltage divider resistor;
a second voltage divider resistor; and
a diode,
wherein the output pin is connected to one end of the current sampling resistor,
wherein a negative input end of the first operational amplifier is connected to one end of a first voltage conversion resistor,
wherein the other end of the first voltage conversion resistor is connected to the one end of the current sampling resistor,
wherein a positive input end of the first operational amplifier is connected to one end of a second voltage conversion resistor,
wherein the other end of the second voltage conversion resistor is connected to the other end of the current sampling resistor,
wherein an output end of the first operational amplifier is connected to a base of the triode,
wherein an emitter of the triode is connected to the negative input end of the first operational amplifier,
wherein a collector of the triode is connected to one end of a third voltage conversion resistor,
wherein the other end of the third voltage conversion resistor is grounded, wherein the first voltage divider resistor is connected to the second voltage divider resistor in series,
wherein one end of the first voltage divider resistor is connected to the other end of the current sampling resistor,
wherein one end of the second voltage divider resistor is grounded,
wherein a positive electrode of the diode is connected to the one end of the third voltage conversion resistor,
wherein a negative electrode of the diode is separately connected to the other end of the second voltage divider resistor and the feedback pin,

wherein the power supply chip is configured to:
convert an input first voltage into a second voltage; and
output the second voltage to the current-limiting circuit using the output pin,

wherein the current-limiting circuit is configured to:
detect a first current that passes through the current sampling resistor;
convert the first current into a third voltage using the at least one voltage conversion resistors, the first operational amplifier, and the triode;
output a first reference voltage using the first voltage divider resistor and the second voltage divider resistor; and
output a feedback voltage to the feedback pin according to the third voltage and the first reference voltage,

wherein the power supply chip is further configured to reduce the second voltage until the first current reaches a preset value when the feedback voltage is greater than a second reference voltage, and
wherein the second reference voltage is a preset internal voltage of the power supply chip.

2. The current-limiting protection circuit according to claim 1 , wherein the current-limiting circuit further comprises a second operational amplifier, and wherein a positive electrode of the diode is connected to the one end of the third voltage conversion resistor, and a negative electrode of the diode is separately connected to the other end of the second voltage divider resistor and the feedback pin corresponds to:
a positive input end of the second operational amplifier connected to the other end of the second voltage divider resistor;
a negative input end of the second operational amplifier connected to the one end of the third voltage conversion resistor; and
an output end of the second operational amplifier connected to the positive electrode of the diode;
wherein the negative electrode of the diode is separately connected to the negative input end of the second operational amplifier and the feedback pin.

3. The current-limiting protection circuit according to claim 1 , wherein outputting the feedback voltage to the feedback pin comprises that:
the feedback voltage is a difference between the third voltage and a positive break-over voltage of the diode when the third voltage is greater than a sum of the first reference voltage and the positive break-over voltage of the diode; and
the feedback voltage is the first reference voltage when the third voltage is less than or equal to the sum of the first reference voltage and the positive break-over voltage of the diode.

4. The current-limiting protection circuit according to claim 2 , wherein outputting the feedback voltage to the feedback pin comprises that:
the feedback voltage is the third voltage when the third voltage is greater than the first reference voltage; and
the feedback voltage is the first reference voltage when the third voltage is less than or equal to the first reference voltage.

5. An electronic device, comprising:
a current-limiting protection circuit; and
a power supply interface coupled to the current-limiting protection circuit,
wherein the power supply interface is configured to connect to a load such that the electronic device supplies power to the load,
wherein the current-limiting protection circuit comprises:
a power supply chip; and
a current-limiting circuit coupled to the power supply chip,
wherein the power supply chip comprises:
an output pin; and
a feedback pin,

wherein the current-limiting circuit comprises:
a current sampling resistor;
at least one voltage conversion resistor;
a first operational amplifier;
a triode;
a first voltage divider resistor;
a second voltage divider resistor; and
a diode,
wherein the output pin is connected to one end of the current sampling resistor,
wherein a negative input end of the first operational amplifier is connected to one end of a first voltage conversion resistor,
wherein the other end of the first voltage conversion resistor is connected to the one end of the current sampling resistor,
wherein a positive input end of the first operational amplifier is connected to one end of a second voltage conversion resistor,
wherein the other end of the second voltage conversion resistor is connected to the other end of the current sampling resistor,
wherein an output end of the first operational amplifier is connected to a base of the triode,
wherein an emitter of the triode is connected to the negative input end of the first operational amplifier,
wherein a collector of the triode is connected to one end of a third voltage conversion resistor,
wherein the other end of the third voltage conversion resistor is grounded,
wherein the first voltage divider resistor is connected to the second voltage divider resistor in series,
wherein one end of the first voltage divider resistor is connected to the other end of the current sampling resistor,
wherein one end of the second voltage divider resistor is grounded,
wherein a positive electrode of the diode is connected to the one end of the third voltage conversion resistor,
wherein a negative electrode of the diode is separately connected to the other end of the second voltage divider resistor and the feedback pin,

wherein the power supply chip is configured to:
convert an input first voltage into a second voltage; and
output the second voltage to the current-limiting circuit using the output pin,

wherein the current-limiting circuit is configured to:
detect a first current that passes through the current sampling resistor;
convert the first current into a third voltage using the at least one voltage conversion resistors, the first operational amplifier, and the triode;
output a first reference voltage using the first voltage divider resistor and the second voltage divider resistor; and
output a feedback

Assignees

• Huawei Tech Co Ltd

Inventors

• Liu Shengcai

Classifications

• G05F1/5735

  with foldback current limiting · CPC title

• H02H9/02 Primary

  responsive to excess current {(current limitation for voltage regulators G05F1/573; disconnection after limiting H02H3/025)} · CPC title