Final Electrical Specifications
LTC3722-1/LTC3722-2
Synchronous Dual Mode
Phase Modulated
Full Bridge Controllers
February 2003
U
DESCRIPTIO
FEATURES
TheLTC®3722-1/LTC3722-2phaseshiftPWMcontrollers
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.
■
Adaptive or Manual Delay Control for Zero Voltage
Switching Operation
■
Adjustable Synchronous Rectification Timing for
Highest Efficiency
Adjustable Maximum ZVS Delay
■
■
Adjustable System Undervoltage Lockout and
Hysteresis
■
Programmable Leading Edge Blanking
■
Very Low Start-Up and Quiescent Currents
The LTC3722-1/LTC3722-2 feature adjustable synchro-
nous rectifier timing for optimal efficiency. A UVLO pro-
gram input provides accurate system turn-on and turn-off
voltages. The LTC3722-1 features peak current mode
controlwithprogrammableslopecompensationandlead-
ing edge blanking, while the LTC3722-2 employs voltage
mode control with voltage feedforward capability.
■
Current Mode (LTC3722-1) or Voltage Mode
(LTC3722-2) Operation
■
Programmable Slope Compensation
■
VCC UVLO and 25mA Shunt Regulator
■
50mA Output Drivers
■
Soft-Start, Cycle-by-Cycle Current Limiting and
Hiccup Mode Short-Circuit Protection
■
The LTC3722-1/LTC3722-2 feature extremely low operat-
ingandstart-upcurrents. Bothdevicesincludeafullrange
of protection features and are available in the 24-pin
surface mount (GN) package.
5V, 15mA Low DUropout Regulator
APPLICATIO S
■
Telecommunications, Infrastructure Power Systems
, LTC and LT are registered trademarks of Linear Technology Corporation.
■
Distributed Power Architectures
Server Power Supplies
■
U
TYPICAL APPLICATIO
V
IN
36V TO 72V
C
IN
R1
12VOUT, 240W Converter Efficiency
95
36V
IN
MA
MC
MD
T1
LTC3722
90
85
80
75
L1
L2
48V
V
IN
OUT
12V
72V
IN
C
OUT
MB
1/2
U1
1/2
U1
U2
ME
RCS
T2
C1
MF
0
2
4
6
8
10 12 14 16 18 20
CURRENT (A)
3722 • TA01A
U1, U2: LTC1693-1 DUAL GATE DRIVER
3722 TA01b
372212i
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.
1