The overlap of the voltage and current of power MOSFET will leads large power loss when power MOSFET in a ballast turns on. To solve this problem, a self-adaptive ZVS protection circuit is proposed, which consists of a dead time control circuit and a ZVS control circuit. Compared with traditional circuit with fixed dead time, it can regulate the dead-time automatically to realize ZVS with a negative feedback loop and result reduction advantages come from, such as the induction of power loss and EMI, meanwhile the efficiency is improved. Hspice simulation shows that the ZVS protection circuit in the ballast with an input voltage of 14V and an operation frequency of 50 kHz can realize the self-adaptive dead time.
