The UCC35701/UCC35702 family of pulse width modulators is intended for isolated switching power supplies using primary side control. They can be used for both off-line applications and DC/DC converter designs such as in a distributed power system architecture or as a telecom power source.

The devices feature low startup current, allowing for efficient off-line starting, yet have sufficient output drive to switch power MOSFETs in excess of 500kHz.

Voltage feed forward compensation is operational over a 5:1 input range and provides fast and accurate response to input voltage changes over a 4:1 range. An accurate volt-second clamp and maximum duty cycle limit are also featured.

Fault protection is provided by pulse by pulse current limiting as well as the ability to latch off after a programmable number of repetitive faults has occurred.