Patent ID: 8085559

Claim:
A resonant converter circuit configured to convert an input voltage to an output voltage, the resonant converter circuit comprising: an LC resonant circuit configured to receive the input voltage; a first drive transistor and a second drive transistor on a primary side of a transformer; an error amplifier configured to generate an error voltage indicative of a level of the output voltage; an integrator configured to generate an integration signal by integrating another signal indicative of current flowing through the first drive transistor when the first drive transistor is switched ON; a summer configured to generate a quasi-sawtooth signal by adding the integration signal to a sawtooth signal; and a control circuit configured to switch OFF the first drive transistor when the quasi-sawtooth signal increases to a level of the error voltage, wherein once the first drive transistor is switched OFF, the control circuit switches ON the second drive transistor such that the first and second drive transistors each has a duty cycle of 50%.