AP3125 AC/DC PWM Controllers

Diodes Incorporated AP3125 AC/DC PWM Controllers are optimized for high performance and low standby power in cost-effective offline fly-back converters. Designed to improve operating efficiency and eliminate no-load losses, AP3125 devices feature three operating modes. In normal mode, the switching frequency is either 65kHz or 100kHz under full load. At lighter loads, the AP3125 controllers automatically enter green mode, where frequency fold-back is used to back-off the frequency and raise average efficiency. Finally, in conditions of no-load or a very light load, AP3125 devices enter a burst mode to minimize standby power. To help minimize audible noise in the system, the SOT26-packaged AP3125 controllers have a minimum switching frequency setting of 20kHz, while a built-in frequency dithering function in normal and green modes ensures a reduction in EMI emissions. In order to help increase system reliability, AP3125 controllers integrate a complete range of protection functions. Internal over-temperature protection and fast over-current protection are included, along with over-voltage and overload protection. The AP3125B and AP3125HB variants also integrate brownout and line over-voltage protection, easily configured using a few divider resistors.