LTC3722-1/LTC3722-2
Synchronous Dual Mode
Phase Modulated
Full Bridge Controllers
DESCRIPTION
The LTC®3722-1/LTC3722-2 phase-shift PWM controllers
provide all of the control and protection functions neces-
sary to implement a high efficiency, zero voltage switched
(ZVS), full bridge power converter. Adaptive ZVS circuitry
delays the turn-on signals for each MOSFET independent
of internal and external component tolerances. Manual
delay set mode enables secondary side control operation
or direct control of switch turn-on delays.
FEATURES
n
Adaptive or Manual Delay Control for Zero Voltage
Switching Operation
n
Adjustable Synchronous Rectification Timing for
Highest Efficiency
Adjustable Maximum ZVS Delay
n
n
Adjustable System Undervoltage Lockout Hysteresis
n
Programmable Leading Edge Blanking
n
Very Low Start-Up and Quiescent Currents
n
Current Mode (LTC3722-1) or Voltage Mode
The LTC3722-1/LTC3722-2 feature adjustable synchron-
ousrectifiertimingforoptimalefficiency.AUVLOprogram
input provides accurate system turn-on and turn-off
voltages. The LTC3722-1 features peak current mode
control with programmable slope compensation and
leading edge blanking, while the LTC3722-2 employs
voltage mode control.
(LTC3722-2) Operation
Programmable Slope Compensation
n
n
V
UVLO and 25mA Shunt Regulator
CC
n
n
50mA Output Drivers
Soft-Start, Cycle-by-Cycle Current Limiting and
Hiccup Mode Short-Circuit Protection
5V, 15mA Low Dropout Regulator
24-Pin Surface Mount GN Package
n
n
TheLTC3722-1/LTC3722-2featureextremelylowoperating
and start-up currents. Both devices include a full range of
protection features and are available in the 24-pin surface
mount GN package.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
DirectSense is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
APPLICATIONS
n
Telecommunications, Infrastructure Power Systems
n
Distributed Power Architectures
n
Server Power Supplies
TYPICAL APPLICATION
V
IN
36V TO
72V
C
R1
IN
12VOUT, 240W Converter Efficiency
U2
U1
95
MA
MC
36V
IN
T1
90
85
80
75
L1
L2
LTC3722
V
OUT
12V
48V
IN
72V
IN
C
OUT
MB
MD
T2
RCS
ME
0
2
4
6
8
10 12 14 16 18 20
CURRENT (A)
U3
C1
MF
372212 TA01b
U1, U2: LTC4440 GATE DRIVER
U3: LTC3901 GATE DRIVER
372212 TA01a
372212fb
1
For more information www.linear.com/LTC3722