UCC3829-1 Datasheet, PDF (1/11 Pages) Texas Instruments – High Speed PWM Controller

UCC1829-1/-2/-3
UCC2829-1/-2/-3
UCC3829-1/-2/-3
High Speed PWM Controller
PRELIMINARY
FEATURES
• Compatible with Voltage or Current
Mode Control Methods
• Practical Operation at Switching
Frequencies to 4MHz
• 50ns Propagation Delay to Output
• High Current Complementary
Outputs
• Programmable Dead Time and
Frequency Oscillator
• Pulse by Pulse Current Limiting
• Latched Overcurrent Comparator
with Full Cycle Restart
• Programmable Undervoltage
Lockout (UVLO)
• Adjustable Blanking for Leading
Edge Noise Tolerance
DESCRIPTION
The UCC3829 is a BiCMOS High Speed PWM Controller IC. It is opti-
mized for high frequency switched mode power supply applications. The
IC can be used in both voltage mode and current mode control applica-
tions. Care was given to minimizing the propagation delays through the
comparators and logic circuitry while maximizing the bandwidth and slew
rate of the error amplifier. The oscillator frequency and deadtime can be
programmed via two external resistors and a capacitor. The undervolt-
age lockout threshold can be programmed using an external resistor di-
vider. The current limit and overcurrent threshold can be set externally.
The IC is available in push-pull (-1), single ended (-2), or complementary
(-3) output configuration.
Fault protection circuitry includes undervoltage detection for the internal
bias supply, and overcurrent detection. The fault detection logic sets a
latch that ensures full discharge of the soft start capacitor before allowing
a restart. While the fault latch is set, the outputs are in a low state. In the
event of continuous faults, the soft start capacitor is fully charged before
discharging to insure that the fault frequency does not exceed the de-
signed soft start period.
BLOCK DIAGRAM
BISYNC 9
RT1 8
CT 7
RT2 6
LEB 19
RAMP 5
V_BIAS
CLOCK
4V
1.5V
PWCONT 4
EAOUT 3
NINV 1
INV 2
V_BIAS
SQ
RQ
1.2V
SS 10
GND 18
SQ
1V
R_{D Q}
SLUS390 - MARCH 1998
>Q
T
Q
V_BIAS
0.9V
1.25V
3V
REFERENCE
14.2V/9V
3V/2.5V
2.1V
18 VDD
15 OUTA
14 OUTB
13 PGND
11 CL+
12 CL–
17 UVLO
23 VREF
UDG-98043