Charger circuit with thermal regulation circuit

Patent metadata

Field	Value
Publication number	US-12549029-B2
Application number	US-202218073593-A
Country	US
Kind code	B2
Filing date	Dec 2, 2022
Priority date	Dec 2, 2022
Publication date	Feb 10, 2026
Grant date	Feb 10, 2026

Abstract

A charger circuit comprises a constant current charging circuit and a thermal regulation circuit. The constant current charging circuit is configured for generating a charging current, including a charger input terminal for receiving an input voltage, a charge current setting terminal, a charger output terminal for outputting the charging current, a current mirror including a reference current path between the charger input terminal and charge current setting terminal and an output current path between the charger input terminal and charger output terminal, and a feedback amplifier having a positive terminal, a negative terminal for receiving a feedback reference voltage, and a feedback output terminal coupled to the current mirror. The thermal regulation circuit is configured for generating and modulating a thermal regulation voltage with temperature, and outputting the thermal regulation voltage across the positive terminal of the feedback amplifier and the charging current setting terminal.

First claim

What is claimed is:

1 . A charger circuit, comprising:
a constant current charging circuit for generating a charging current, including a charger input terminal for receiving an input voltage, a charge current setting terminal, a charger output terminal for outputting the charging current, a current mirror including a reference current path between the charger input terminal and the charge current setting terminal and including an output current path between the charger input terminal and the charger output terminal, and a feedback amplifier having a positive terminal, a negative terminal for receiving a feedback reference voltage, and a feedback output terminal coupled to the current mirror; and a thermal regulation circuit coupled to the positive terminal of the feedback amplifier and the charging current setting terminal, for generating and modulating a thermal regulation voltage with temperature, and outputting the thermal regulation voltage across the positive terminal of the feedback amplifier and the charging current setting terminal.

2 . The charger circuit according to claim 1 , wherein the constant current charging circuit further comprises:
a first transistor disposed in the reference current path; a second transistor disposed in the output current path, wherein a control terminal of the first transistor and a control terminal of the second transistor are coupled to the feedback output terminal; a third transistor disposed in the reference current path and coupled between the first transistor and the charge current setting terminal; and an operational amplifier having a negative terminal coupled to the reference current path, a positive terminal coupled to the output current path, and an output terminal coupled to a control terminal of the third transistor.

3 . The charger circuit according to claim 1 , wherein the constant current charging circuit further comprises:
a first P-type transistor in the reference current path, wherein a source terminal of the first P-type transistor is coupled to the input voltage; a second P-type transistor in the output current path, wherein a source terminal of the second P-type transistor is coupled to the input voltage, a drain terminal of the second P-type transistor is coupled to the charger output terminal, and a gate terminal of the second P-type transistor is coupled to a gate terminal of the first P-type transistor; a third P-type transistor in the reference current path, wherein a source terminal of the third P-type transistor is coupled to a drain terminal of the first P-type transistor, a drain terminal of the third P-type transistor is coupled to the charge current setting terminal; and an operational amplifier having a negative terminal coupled to the source terminal of the third P-type transistor, a positive terminal coupled to the drain terminal of the second P-type transistor, and an output terminal coupled to a gate terminal of the third P-type transistor.

4 . The charger circuit according to claim 1 , wherein the thermal regulation circuit comprises:
a voltage-to-current converter configured to generate and modulate a thermal regulation current with temperature according to a temperature sensing voltage and a temperature reference voltage, and having a positive terminal coupled to the temperature sensing voltage, a negative terminal coupled to the temperature reference voltage, and an output terminal to output the thermal regulation current; and a thermal regulation voltage generation circuit configured to generate the thermal regulation voltage with temperature according to the thermal regulation current, and having a regulation input terminal coupled to the voltage-to-current converter, a first output terminal coupled to the positive terminal of the feedback amplifier, and a second output terminal coupled to the charging current setting terminal.

5 . The charger circuit according to claim 4 , wherein the voltage-to-current converter comprises a transconductance amplifier for receiving the temperature sensing voltage and the temperature reference voltage and outputting the thermal regulation current based on a difference between the temperature sensing voltage and the temperature reference voltage.

6 . The charger circuit according to claim 4 , wherein the thermal regulation voltage generation circuit comprises:
a first current source circuit for providing current according to the thermal regulation current receiving from the regulation input terminal; a second current source circuit for providing current according to the thermal regulation current receiving from the regulation input terminal; and an output resistor coupled between the first current source circuit and the second current source circuit, wherein the output resistor has two terminals coupled to the first output terminal and the second output terminal respectively, wherein a voltage across the output resistor is generated as the thermal regulation voltage when the current flows from the output resistor.

7 . The charger circuit according to claim 1 , wherein the thermal regulation circuit generates the thermal regulation voltage according to a difference between a temperature sensing voltage and a temperature reference voltage.

8 . The charger circuit according to claim 7 , wherein a voltage at the charge current setting terminal is obtained according to the feedback reference voltage minus the thermal regulation voltage when the temperature sensing voltage is greater than the temperature reference voltage and a temperature indicated by the temperature sensing voltage is less than a shutdown temperature for the charger circuit.

9 . The charger circuit according to claim 7 , wherein when the temperature indicated by the temperature sensing voltage is equal to or greater than a shutdown temperature for the charger circuit, the thermal regulation voltage generated by the thermal regulation circuit is greater than the feedback reference voltage so that the voltage at the charge current setting terminal is zero.

10 . The charger circuit according to claim 7 , wherein when the thermal regulation voltage generated by the thermal regulation circuit is greater than the feedback reference voltage, the feedback amplifier turns off the current mirror and the voltage at the charge current setting terminal is zero so that the current mirror generates no charging current.

11 . The charger circuit according to claim 7 , wherein the charger circuit has a shutdown temperature regardless of a value of a setting resistor coupled to the charge current setting terminal.

Assignees

• Elite Semiconductor Microelectronics Technology Inc

Inventors

• Yang Yao-Wei

Classifications

• H02J7/80 Primary

  including monitoring or indicating arrangements · CPC title

• H02J7/65

  against overtemperature · CPC title

• H02J7/975 Primary

  in response to temperature · CPC title

• H02J7/0047

  Electricity · mapped topic

• H02J7/00309

  Electricity · mapped topic