Diodes Incorporated AP3301 Quasi-Resonant PWM Controller

At no load or light load, the AP3301 QR PWM Controller will enter the burst mode to minimize standby power consumption. The minimum switching frequency (about 20kHz) is set to avoid audible noise. At medium load, the AP3301 will enter valley lock QR mode with frequency foldback to improve system efficiency and EMI performance. The maximum switching frequency (about 120kHz) is set to clamp the QR frequency to improve efficiency. At low line input and heavy load, when switching frequency decreases below 62KHz with output load increasing, this device will enter CCM mode with a fixed switching frequency of 62kHz to optimize low line power conversion efficiency. Furthermore, the frequency dithering function is built in to reduce EMI emission.

Internal slope compensation allows more stable peak-current mode control over a wide range of input voltage and load conditions. Internal piecewise linear line compensation ensures a constant output power limit over the entire universal line voltage range.

The AP3301 QR POWM Controller offers comprehensive protection features, including brownout protection, cycle-by-cycle current limit (OCP), VCC Over Voltage Protection (VOVP), Secondary-Side Output OVP (SOVP), internal OTP, Over Load Protection (OLP), and Pin Fault Protection.