The quasi-resonant controller typed AC/DC converter IC BM1Q021FJ provides an optimum system for all products that include an electrical outlet. Quasi-resonant operation enables soft switching and helps to keep EMI low. With MOSFET for switching and current detection resistors as external devices, a higher degree of design freedom is achieved. As BM1Q021FJ built in HV starter circuit, it contributes to low consumption power and high speed start. Because the built-in burst mode is reduced switching loss and IC consumption current is low, Stand-by power is very low. Because BM1Q021FJ built-in soft-start, burst mode, over current limiter which is cycle-by-cycle, over load protection, over voltage protection, CS open protection and so on, BM1Q021FJ are highly safety.You can choose from a variety of power and topologyevaluation boards.