The SE3901 is a green-mode Pulse Width Modulation (PWM) controller. It is specifically designed for low power applications such as 5W-20W Adaptors and Off-line battery Chargers. In these typical applications, the low standby power, space saving, and low cost are all required. SE3901 is a perfect solutions to meet these challenges. The typical standby power is only 0.13Watt.

In normal operation, the SE3901 switches on and off at a fixed switching frequency of 60 kHz. With a current limit capability of about 420mA, the SE3901 can directly drive the emitter of a high voltage NPN transistor. When the output power falls below a given level, the IC enters skip cycle mode to reduce power consumption.

The SE3901 also features Under-Voltage Lockout , Over-Temperature Protection, Over-Current and Short Circuit  Protections.

The SE3901 is available in TO-94 Packages.

more:
http://www.seawardinc.com.cn/Products.asp?class_big=AC/DC%20PWM%20Controller&language=zh-cn