UCC1810

UCC2810

UCC3810

02/99

FEATURES

• Single Oscillator Synchronizes Two

PWMs

• 150 A Startup Supply Current

• 2mA Operating Supply Current

• Operation to 1MHz

• Internal Soft Start

• Full-Cycle Fault Restart

• Internal Leading Edge Blanking of the

Current Sense Signal

• 1 Amp Totem Pole Outputs

• 75ns Typical Response from Current

Sense to Output

• 1.5% Tolerance Voltage Reference

DESCRIPTION

The UCC3810 is a high-speed BiCMOS integrated circuit which imple-

ments two synchronized pulse width modulators for use in off-line and

DC-to-DC power supplies.

The UCC3810 provides perfect synchronization between two PWMs by us-

ing 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 en-

sures that one PWM will not slave, interfere, or otherwise affect the other

PWM. This toggle flip flop also ensures that each PWM will be limited to

50% maximum duty cycle, insuring adequate off-time to reset magnetic el-

ements.

This IC 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 re-

moved.

Dual Channel Synchronized Current Mode PWM

BLOCK DIAGRAM

UDG-92062-1