application
INFO
available
UCC1807-1/-2/-3
UCC2807-1/-2/-3
UCC3807-1/-2/-3
Programmable Maximum Duty Cycle PWM Controller
FEATURES
User Programmable Maximum PWM
Duty Cycle
100m A Startup Current
Operation to 1MHz
Internal Full Cycle Soft Start
Internal Leading Edge Blanking of
Current Sense Signal
1A Totem Pole Output
DESCRIPTION
The UCC3807 family of high speed, low power integrated circuits contains
all of the control and drive circuitry required for off-line and DC-to-DC fixed
frequency current mode switching power supplies with minimal external
parts count.
These devices are similar to the UCC3800 family, but with the added fea-
ture of a user programmable maximum duty cycle. Oscillator frequency and
maximum duty cycle are programmed with two resistors and a capacitor.
The UCC3807 family also features internal full cycle soft start and internal
leading edge blanking of the current sense input.
The UCC3807 family offers a variety of package options, temperature
range options, and choice of critical voltage levels. The family has UVLO
thresholds and hysteresis levels for off-line and battery powered systems.
Thresholds are shown in the table below.
Part Number
UCCx807-1
UCCx807-2
UCCx807-3
Turn-on Threshold
7.2V
12.5V
4.3V
Turn-off Threshold
6.9V
8.3V
4.1V
Packages
J
N, D
N, D, PW
BLOCK DIAGRAM
UDG-95001-1
SLUS163 - JUNE 1997
1
TI [ TEXAS INSTRUMENTS ]
