Linear charger with thermal regulation circuit

Patent metadata

Field	Value
Publication number	US-12166372-B2
Application number	US-202117561685-A
Country	US
Kind code	B2
Filing date	Dec 23, 2021
Priority date	Dec 23, 2021
Publication date	Dec 10, 2024
Grant date	Dec 10, 2024

Abstract

A linear charger includes a constant current charging circuit and a thermal regulation circuit. The constant current charging circuit is arranged to generate a charging current, and includes a first transconductance amplifier, wherein the first transconductance amplifier has a positive terminal, a negative terminal, and an output terminal. The thermal regulation circuit is coupled to the output terminal and the negative terminal of the first transconductance amplifier, and is arranged to generate and modulate a thermal regulation current and an amplifier reference voltage with temperature, and transmit the thermal regulation current and the amplifier reference voltage to the output terminal and the negative terminal of the first transconductance amplifier, respectively.

First claim

What is claimed is:

1. A linear charger, comprising:
a constant current charging circuit, arranged to generate a charging current, wherein the constant current charging circuit comprises:
a first transconductance amplifier, having a positive terminal, a negative terminal, and an output terminal; and

a thermal regulation circuit, coupled to the output terminal and the negative terminal of the first transconductance amplifier, and arranged to generate and modulate a thermal regulation current and an amplifier reference voltage with temperature, and transmit the thermal regulation current and the amplifier reference voltage to the output terminal and the negative terminal of the first transconductance amplifier, respectively.

2. The linear charger of claim 1 , wherein the constant current charging circuit further comprises:
a first P-type transistor, having a source terminal coupled to a first reference voltage; and
a second P-type transistor, having a source terminal coupled to the first reference voltage, and a gate terminal coupled to a gate terminal of the first P-type transistor;
a third P-type transistor, having a source terminal coupled to a drain terminal of the first P-type transistor;
an operation amplifier, having a positive terminal coupled to the source terminal of the third P-type transistor, a negative terminal coupled to a drain terminal of the second P-type transistor, and an output terminal coupled to a gate terminal of the third P-type transistor; and
a setting resistor, having a first terminal coupled to the positive terminal of the first transconductance amplifier, and a second terminal coupled to a second reference voltage; wherein the positive terminal of the first transconductance amplifier is coupled to a drain terminal of the third P-type transistor, the negative terminal of the first transconductance amplifier is coupled to the second reference voltage, and the output terminal of the first transconductance amplifier is coupled to the gate terminal of the first P-type transistor.

3. The linear charger of claim 2 , wherein a shutdown temperature of the linear charger is unchanged for different values of the setting resistor.

4. The linear charger of claim 2 , wherein the charging current is output from the drain terminal of the second P-type transistor, and a shutdown temperature of the linear charger is unchanged for the charging current corresponding to different current values.

5. The linear charger of claim 4 , wherein modulation of the charging current with temperature is linear.

6. The linear charger of claim 1 , wherein the thermal regulation circuit comprises:
a second transconductance amplifier, arranged to generate and modulate the thermal regulation current with temperature according to a sensing voltage and a temperature reference voltage, and having a positive terminal coupled to the sensing voltage, a negative terminal coupled to the temperature reference voltage, and an output terminal coupled to the output terminal of the first transconductance amplifier; and
an amplifier reference voltage generation circuit, coupled to the negative terminal of the first transconductance amplifier, and arranged to generate and modulate the amplifier reference voltage with temperature according to the sensing voltage and the temperature reference voltage.

7. The linear charger of claim 6 , wherein the amplifier reference voltage generation circuit comprises:
a voltage source, having a first terminal coupled to a reference voltage;
a first resistor, having a first terminal coupled to a second terminal of the voltage source, and a second terminal coupled to the negative terminal of the first transconductance amplifier;
a second resistor, having a first terminal coupled to the second terminal of the first resistor, and a second terminal coupled to the reference voltage; and
a third transconductance amplifier, arranged to modulate the amplifier reference voltage with temperature according to the sensing voltage and the temperature reference voltage, and having a positive terminal coupled to the temperature reference voltage, a negative terminal coupled to the sensing voltage, and an output terminal coupled to the second terminal of the first resistor.

8. The linear charger of claim 1 , wherein an offset voltage is applied to the first transconductance amplifier by the thermal regulation current before modulation of the amplifier reference voltage with temperature becomes nonlinear, to make modulation of a setting voltage at the positive terminal of the first transconductance amplifier with temperature linear.

9. The linear charger of claim 8 , wherein a voltage value of the offset voltage is equal to a voltage value generated by subtracting the setting voltage from the amplifier reference voltage.

10. The linear charger of claim 8 , wherein a current value of the thermal regulation current is equal to a current value generated by multiplying a gain of the first transconductance amplifier and the offset voltage.

Assignees

• Elite Semiconductor Microelectronics Technology Inc

Inventors

• Yang Yao-Wei

Classifications

• H02J7/96 Primary

  in response to battery voltage · CPC title

• H02J7/94

  in response to battery current · CPC title

• H02J7/975 Primary

  in response to temperature · CPC title

• H02J7/04

  Regulation of charging current or voltage · CPC title

• H02J7/007182

  Electricity · mapped topic