Patent ID: 8441813

Claim:
A maximize efficiency method for resonant converter with self-adjusting switching points, wherein said resonant converter comprises a transformer having a primary winding and a second winding and an N-channel metal oxide semiconductor field effect transistor (NMOSFET), and wherein said primary winding is connected a high voltage terminal and a drain of said NMOSFET, and a source of said NMOSFET is connected with a reflected voltage terminal; said method comprising steps of: Step (A): turning on said NMOSFET whereby first energy from said high voltage terminal is stored in said primary winding; Step (B): turning off said NMOSFET whereby said first energy is discharged from said second winding and a first resonant signal is generated at said drain, wherein a voltage of said first resonant signal is gradually close to a high voltage of said high voltage terminal plus a reflected voltage of said reflected voltage terminal, wherein said high voltage plus said reflected voltage equals a crossing voltage; Step (C): recording a first period between a start time point and a cross time point of said first resonant signal when said voltage of said first resonant signal first reaches to said crossing voltage corresponding to said cross time point; and Step (D): turning on said NMOSFET after a prediction time equal to said first period.