Research Of Standby Control In LLC Resonant Converter

In recent years, with the popularization of household electronics and the development of office automation, more electronics have standby operation function which forms huge waste of energy resource and pressure on environment conservation. So reducing power consumption in standby operation becomes one of the key research points in home and abroad.In standby operation, the conduction loss can be ignored for the output current is almost zero. Switching loss and control circuit consumption make up the main standby operation loss. Switching loss tightly depends on switching frequency which should be decreased to reduce the loss. And the control circuit consumption is related to the controller and the feedback circuit. Nowadays, the power supply in household and office electronics usually adopts PWM controlled converter. And the standby mode control mainly focuses on PWM controlled converters while less on resonant mode controlled converters. Some new studies attempt to adopt the resonant power supply in consumer and office electronics. So research on standby mode control in the field is getting more and more significant.This paper investigated on the standby mode control of LLC resonant converter and proposed a new design of control circuit with standby mode operation. In the new design, current in the switch is sensed to judge the operation mode while the feedback voltage is sensed to control the output voltage in the standby mode. Simulation and experiment results indicated that the design can effectively realize the standby function.