The invention relates to a feedback-based self-adaptive
grid voltage regulation synchronous rectification method and a
chip, which are executed in a synchronous rectification
chip of a power supply circuit. A
voltage signal VKA between the drain
electrode and the source
electrode of the synchronous rectification MOS tube is detected, a feedback
signal V 'KA is formed through adaptive filtering, and the driving module dynamically adjusts the
grid voltage Vgs according to the V' KA. When the V 'KA is lower than a conduction
detection threshold VON, the MOS tube is completely conducted; when the V 'KA rises to be close to a pre-turn-off trigger threshold value VREADY-OFF, the Vgs is dynamically reduced to increase the
on resistance, so that the MOS tube is kept in an incomplete conduction state; in the state, the V 'KA is continuously monitored, when the V' KA is lower than the VON again, complete conduction is recovered, only when the V 'KA continuously rises and reaches a turn-off threshold VOFF, the MOS tube is completely turned off, and if the above conditions are not met, the MOS tube is maintained in an incomplete conduction state. According to the adaptive closed-loop adjustment method, the
conduction loss and the grid driving loss can be effectively reduced, and the power supply conversion efficiency and the
system reliability are improved.