The CS51221 fixed frequency feed forward voltage mode PWM controller contains all of the features necessary for basic voltage mode operation. This PWM controller has been opti- mized for high frequency prima- ry side control operation. In addition, this device includes such features as: Soft Start, accu- rate duty cycle limit control, less than 50µA startup current, over and under voltage protection, and bidirectional synchroniza- tion. The CS51221 is available in 16 lead PDIP and SO narrow surface mount pa