Charge field-effect transistor linear charging regulator

Patent metadata

Field	Value
Publication number	US-2025253699-A1
Application number	US-202418936365-A
Country	US
Kind code	A1
Filing date	Nov 4, 2024
Priority date	Feb 6, 2024
Publication date	Aug 7, 2025
Grant date	—

Abstract

A charge field-effect linear charger for charging a battery may include a charge pump configured to drive a field-effect transistor external to the charge field-effect linear charger and a variable output impedance for the charge pump, the variable output impedance depending on a mode of operation of the charge field-effect linear charger and an impedance of the field-effect transistor.

First claim

What is claimed is:

1 . A charge field-effect linear charger for charging a battery, comprising:
a charge pump configured to drive a field-effect transistor external to the charge field-effect linear charger; and a variable output impedance for the charge pump, the variable output impedance depending on a mode of operation of the charge field-effect linear charger and an impedance of the field-effect transistor.

2 . The charge-field effect linear charger of claim 1 , further comprising sensing circuitry for sensing a voltage across a sense resistor external to the charge field-effect linear charger and indicative of a current through the battery, the sensing circuitry comprising:
a variable gain amplifier having its inputs configured to couple to respective terminals of the sense resistor; and an integrator configured to integrate an output of the variable gain amplifier.

3 . The charge-field effect linear charger of claim 2 , further comprising a feedforward compensation capacitor coupled at the output of the integrator and configured to provide feedforward compensation of a gate capacitance of the field-effect transistor.

4 . The charge-field effect linear charger of claim 2 , further comprising a pull-down stage coupled to the field-effect transistor and the output of the integrator and configured to regulate a voltage on a gate terminal of the field-effect transistor.

5 . The charge-field effect linear charger of claim 4 , wherein the pull-down stage includes a variable source impedance for varying a pull-down strength of the pull-down stage.

6 . The charge-field effect linear charger of claim 5 , wherein the variable source impedance is actively adapted based on capacitive sensing of a gate capacitance of the field-effect transistor.

7 . A method for charging a battery with a charge field-effect linear charger, the method comprising:
driving a field-effect transistor external to the charge field-effect linear charger with a charge pump of the charge field-effect linear charger; and varying a variable output impedance for the charge pump depending on a mode of operation of the charge field-effect linear charger and an impedance of the field-effect transistor.

8 . The method of claim 7 , further comprising sensing a voltage across a sense resistor external to the charge field-effect linear charger and indicative of a current through the battery using sensing circuitry, the sensing circuitry comprising:
a variable gain amplifier having its inputs configured to couple to respective terminals of the sense resistor; and an integrator configured to integrate an output of the variable gain amplifier.

9 . The method of claim 8 , further comprising providing feedforward compensation of a gate capacitance of the field-effect transistor with a feedforward compensation capacitor coupled at the output of the integrator.

10 . The method of claim 8 , further comprising regulating a voltage on a gate terminal of the field-effect transistor with a pull-down stage coupled to the field-effect transistor and the output of the integrator.

11 . The method of claim 10 , further comprising varying a pull-down strength of the pull-down stage with a variable source impedance of the pull-down stage.

12 . The method of claim 11 , further comprising actively adapting the variable source impedance based on capacitive sensing of a gate capacitance of the field-effect transistor.

Assignees

• Cirrus Logic Int Semiconductor Ltd

Inventors

• Deems Brendan T
• Bhattacharya Anindya
• Cai Qi
• Turkson Richard
• King Eric J
• Hadden William O

Classifications

• H02J7/96 Primary

  in response to battery voltage · CPC title

• H02J2207/20

  Charging or discharging characterised by the power electronics converter · CPC title

• H02J7/007182 Primary

  Electricity · mapped topic