Synchronous rectifier circuit, control circuit and control method thereof
AssigneeSilergy Semiconductor Technology (Hangzhou) LTD
InventorsChaojun Chen, Jian Deng, Jin Jin
Life of this patent
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Abstract
A method of controlling a synchronous rectifier circuit can include: adjusting a falling amplitude of a drive voltage of a synchronous rectifier switch in the synchronous rectifier circuit in a pull-down mode; adjusting a shielding time during which the synchronous rectifier switch is in a turn-off shielding mode and is not to be turned off; turning off the synchronous rectifier switch after a drain-source voltage of the synchronous rectifier switch reaches a turn-off threshold; and where the falling amplitude of the drive voltage in the pull-down mode and the shielding time for a current period are adjusted according to an operation state of the synchronous rectifier switch in a previous period.
Claims20
A method of controlling a synchronous rectifier circuit, the method comprising:
- a) adjusting a falling amplitude of a drive voltage of a synchronous rectifier switch in the synchronous rectifier circuit in a pull-down mode;
- b) adjusting a shielding time during which the synchronous rectifier switch is in a turn-off shielding mode and is not to be turned off;
- c) turning off the synchronous rectifier switch after a drain-source voltage of the synchronous rectifier switch reaches a turn-off threshold;
- and
- d) wherein the falling amplitude of the drive voltage in the pull-down mode and the shielding time for a current period are adjusted according to an operation state of the synchronous rectifier switch in a previous period.
A control circuit for a synchronous rectifier circuit, the control circuit comprising:
- a) a sampling circuit configured to obtain a drain-source voltage of a synchronous rectifier switch in the synchronous rectifier circuit;
- and
- b) a drive control circuit configured to adjust a drive voltage of the synchronous rectifier switch according to the drain-source voltage, and to adjust a shielding time during which the synchronous rectifier switch is controlled not to be turned off in a turn-off shielding mode.
Dependencies are inferred from the claim text.