UCC2810, UCC3810
SLUS162C − FEBRUARY 1999 − REVISED NOVEMBER 2004
DUAL CHANNEL SYNCHRONIZED
CURRENT-MODE PWM
FEATURES
D
Single Oscillator Synchronizes Two PWMs
D
150-µA Startup Supply Current
D
2-mA Operating Supply Current
D
Operation to 1 MHz
D
Internal Soft-Start
D
Full-Cycle Fault Restart
D
Internal Leading-Edge Blanking of the
D
D
D
Current Sense Signal
1-A Totem Pole Outputs
75-ns Typical Response from Current Sense
to Output
1.5% Tolerance Voltage Reference
N PACKAGE
(TOP VIEW)
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.
ERROR AMPLIFIER GAIN AND PHASE
vs
FREQUENCY
SYNC
CT
RT
FB1
COMP1
CS1
OUT1
GND
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
VCC
REF
ENABLE2
FB2
COMP2
CS2
OUT2
PWRGND
DW PACKAGE
(TOP VIEW)
SYNC
CT
RT
FB1
COMP1
CS1
OUT1
GND
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
VCC
REF
ENABLE2
FB2
COMP2
CS2
OUT2
PWRGND
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
Copyright
2004, Texas Instruments Incorporated
www.ti.com
1
TI [ TEXAS INSTRUMENTS ]
