Description

The AP3125X is a current mode PWM controller which is optimized for high performance, low standby power and cost effective offline fly-back converters. It is available in SOT26 package.

The PWM switching frequency at normal operation is internally fixed (about 65kHz/100kHz). In middle load, IC will enter green mode to improve system efficiency with the help of frequency fold-back. A minimum switching frequency (about 20kHz) is set to avoid the audible noise. In no load or light load, the IC will enter the burst mode to minimize standby power. Furthermore, the frequency dithering function is built-in to reduce EMI emission.

Internal slope compensation allows more stable Peak-Current Mode control over wide range of input voltage and load conditions. Internal line compensation ensures constant output power limit over entire universal line voltage range.

Comprehensive protection features are included, such as cycle-by-cycle current limit (OCP), VCC Over Voltage Protection (VOVP), internal OTP, Over Load Protection (OLP) and pins’ fault protection.

The versatile latch/auto functions can be implemented using a minimal number of external components by CTRL pin.

Application(s)

Switching AC-DC Adapter/Charger

ATX/BTX Auxiliary Power

Set-top Box (STB) Power Supply

Open Frame Switching Power Supplys