UC3578

The UC3578 is a PWM controller with an integrated high side floating gate river. It is used in buck step down converters and regulates a positive utput voltage. Intended to be used in a distributed power system, the IC llows operation from 14V to 72V input voltage which range includes the revalent telecomm bus voltages. The output duty cycle of the UC3578 an vary between 0% and 90% for operation over the wide input voltage nd load conditions.

The UC3578 simplifies the design of the single switch PWM buck converter y incorporating a floating high side driver for an external N-channel OSFET switch. It also features a 100kHz fixed frequency oscillator, an nternal 2V precision reference, an error amplifier configured for voltage ode operation, and a PWM comparator with latching logic. Complementing he traditional voltage mode control block, the UC3578 incorporates n overcurrent shutdown circuit with full cycle soft re-start to limit the nput current to a user defined maximum value during overload operation.  dditional functions include an under voltage lockout circuit to insure that ufficient input supply voltage is present before any switching activity can ccur.

The UC2578 and the UC3578 are both available in surface mount and hru-hole power packages.