Not Recommended for New Designs
application INFO available
Buck Pulse Width Modulator Stepdown Voltage Regulator
UC25...
Not Recommended for New Designs
application INFO available
Buck Pulse Width Modulator Stepdown
Voltage Regulator
UC2578 UC3578
FEATURES Provides Simple Single Inductor Buck
PWM Step-Down
Voltage Regulation
Drives External High Side NMOS Switch
14V to 72V Input
Voltage Operating Range
Contains 100kHz Internal Oscillator, 2V Reference and UVLO
Soft Start on Power Up
Overcurrent Shutdown Followed by Soft Start
DESCRIPTION
The UC3578 is a PWM controller with an integrated high side floating gate driver. It is used in buck step down converters and regulates a positive output
voltage. Intended to be used in a distributed power system, the IC allows operation from 14V to 72V input
voltage which range includes the prevalent telecomm bus
voltages. The output duty cycle of the UC3578 can vary between 0% and 90% for operation over the wide input
voltage and load conditions.
The UC3578 simplifies the design of the single switch PWM buck converter by incorporating a floating high side driver for an external N-channel
MOSFET switch. It also features a 100kHz fixed frequency oscillator, an internal 2V precision reference, an error amplifier configured for
voltage mode operation, and a PWM comparator with latching logic. Complementing the traditional
voltage mode control block, the UC3578 incorporates an overcurrent shutdown circuit with full cycle soft re-start to limit the input current to a user defined maximum value during overload operation. Additional functions include...