Patent ID: 11929684
Assignee: SHANGHAI BRIGHT POWER SEMICONDUCTOR CO., LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 0:
1. A control circuit for an isolated power supply, the control circuit comprising:
a secondary-side control signal generator configured to receive a signal characterizing a voltage of a secondary-side winding in the isolated power supply and generate a secondary-side transistor switch control signal containing information about a turn-off instant of a secondary-side synchronous rectification transistor, the information about the turn-off instant of the secondary-side synchronous rectification transistor configured to turn off the secondary-side synchronous rectification transistor; and
a primary-side control signal generator configured to receive the secondary-side transistor switch control signal and a feedback signal of an output voltage of the isolated power supply and responsively generate a primary-side transistor switch control signal indicating a turn-on instant for a primary-side transistor switch,
wherein the primary-side control signal generator is configured to:
determine a second turn-on instant referring to the turn-off instant of the secondary-side synchronous rectification transistor according to the secondary-side transistor switch control signal;
determine a first turn-on instant referring to a supposed turn-on instant for the primary-side transistor switch according to the feedback signal of the output voltage of the isolated power supply; and
determine the turn-on instant for the primary-side transistor switch from the second turn-on instant or the first turn-on instant whichever is later, and responsively generates the primary-side transistor switch control signal.