FEATURES

· Single Oscillator Synchronizes Two PWMs

· 150-μA Startup Supply Current

· 2-mA Operating Supply Current

· Operation to 1 MHz

· Internal Soft-Start

· Full-Cycle Fault Restart

· Internal Leading-Edge Blanking of the Current

Sense Signal

· 1-A Totem Pole Outputs

· 75-ns Typical Response from Current Sense

to Output

· 1.5% Tolerance Voltage Reference

DESCRIPTION

The UCC3810 is a high-speed BiCMOS controller

integrating two synchronized pulse width modulators

for use in off-line and dc-to-dc power supplies. The

UCC3810 family provides perfect synchronization

between two PWMs by usin g the same oscillator.

The oscillator’s sawtooth waveform can be used for

slope compensation if required.

Using a toggle flip-flop to alternate between

modulators, the UCC3810 ensures that one PWM

does not slave, interfere, or otherwise affect the other PWM. This toggle flip- flop also ensures that

each PWM is limited to 50% maximum duty cycle,

insuring adequate off-time to reset magnetic

elements. This device contains many of the same

elements of the UC3842 current mode controller

family, combined with the enhancements of the

UCC3802. This minimizes power supply parts count.

Enhancements include leading edge blanking of the

current sense signals, full cycle fault restart, CMOS

output drivers, and outputs which remain low even

when the supply voltage is removed.