UCC1810
UCC2810
UCC3810
Dual Channel Synchronized Current Mode PWM
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.
BLOCK DIAGRAM
UDG-92062-1
02/99
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