Primary-Side-Regulation PWM Controller

This highly integrated PWM controller provides several features to enhance the performance of flyback converters. The constant-current-control, proprietary topology enables simplified designs without secondary feedback circuitry for battery-charger applications. A proprietary Burst-Mode function with low operation current minimizes standby power consumption. The FAN302UL controller also provides several protections. Cycle-by-cycle current limiting ensures the fixed peak current limit level, even if a short circuit occurs. The gate output is clamped at 15V to protect the power MOS from high gate-source voltage conditions. If either VS OVP or internal OTP is triggered, the circuit enters Latch Mode until AC power is removed. Using FAN302UL, a charger can be implemented with few external components and minimized cost, compared to a conventional design or a linear transformer.