UCC2580-1

Single Ended Active Clamp/Reset PWM UCC1580-1,-2,-3,-4 UCC2580-1,-2,-3,-4 UCC3580-1,-2,-3,-4 FEATURES Provides Auxiliary Switch Activation Complementary to Main Power Switch Drive Programmable deadtime (Turn-on Delay) Between Activation of Each Switch Voltage Mode Control with Feedforward Operation Programmable Limits for Both Transformer Volt- Second Product and PWM Duty Cycle High Current Gate Driver for Both Main and Auxiliary Outputs Multiple Protection Features with Latched Shutdown and Soft Restart Low Supply Current (100 mA Startup, 1.5 mA Operation) DESCRIPTION The UCC3580 family of PWM controllers is designed to implement a variety of active clamp/reset and synchronous rectifier switching converter topologies. While containing all the necessary functions for fixed frequency, high performance pulse width modulation, the additional feature of this design is the inclusion of an auxiliary switch driver which complements the main power switch, and with a programmable deadtime or delay between each transition. The active clamp/reset technique allows operation of single ended converters beyond 50% duty cycle while reducing voltage stresses on the switches, and allows a greater flux swing for the power transformer. This approach also allows a reduction in switching losses by recovering energy stored in parasitic elements such as leakage inductance and switch capacitance. The oscillator is programmed with two resistors and a capacitor to set switching frequency and maximum...