UC1824
UC2824
UC3824
www.ti.com
SLUS326A–MARCH 1997–REVISED JULY 2007
HIGH SPEED PWM CONTROLLER
FEATURES
DESCRIPTION
•
Complementary Outputs
The UC1824 family of PWM control devices is
optimized for high frequency switched mode power
supply applications. Particular care was given to
•
Practical Operation Switching Frequencies to
1 MHz
minimizing
propagation
delays
through
the
•
•
50-ns Propagation Delay to Output
comparators and logic circuitry while maximizing
bandwidth and slew rate of the error amplifier. This
controller is designed for use in either current mode
or voltage mode systems with the capability for input
voltage feed-forward.
High Current Dual Totem Pole Outputs (1.5 A
Peak)
•
•
Wide Bandwidth Error Amplifier
Fully Latched Logic With Double Pulse
Suppression
Protection circuitry includes
a
current limit
comparator with a 1-V threshold, a TTL compatible
shutdown port, and a soft-start pin which doubles as
a maximum duty cycle clamp. The logic is fully
latched to provide jitter free operation and prohibit
multiple pulses at an output. An under-voltage
lockout section with 800 mV of hysteresis assures
low start up current. During under-voltage lockout,
the outputs are high impedance.
•
•
•
•
•
Pulse-by-Pulse Current Limiting
Soft Start/Maximum Duty Cycle Control
Under-Voltage Lockout with Hysteresis
Low Start Up Current (1.1 mA)
Trimmed Bandgap Reference (5.1 V ± 1%)
BLOCK DIAGRAM
Clock
RT
4
5
OSC
PWM Latch (Set Dom.)
R
CT
6
1.25V
Ramp
7
3
S
E/A Out
Wide Bandwidth
(Set Dom.)
NI
2
1
+
VIN
Error
Amp
INV
Inhibit
9mA
13 VC
11 Out
Soft Start
8
9
ILIM
CPRTR
14 INVOUT
1V
12 Pwr Gnd
Shutdown
CPRTR
ILIM/SD
1.4V
Output
Inhibit
Internal
Bias
VCC 15
9V
4V
UVLO
VCC Good
VREF Good
REF
GEN
Gnd 10
GATE
10 VREF 5.1V
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Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 1997–2007, Texas Instruments Incorporated