LT3753_15 Datasheet, PDF (1/36 Pages) Linear Technology – Active Clamp Synchronous Forward Controller

LT3753
Active Clamp Synchronous
Forward Controller
Features
n _{Input Voltage Range: 8.5V to 100V}
n _{Programmable Volt-Second Clamp}
n _{High Efficiency Control: Active Clamp,}
Synchronous Rectification, Programmable Delays
n _{Short-Circuit (Hiccup Mode) Overcurrent Protection}
n _{Programmable Soft-Start/Stop}
n _{Programmable OVLO and UVLO with Hysteresis}
n _{Programmable Frequency (100kHz to 500kHz)}
n _{Synchronizable to an External Clock}
Applications
n _{Industrial, Automotive and Military Systems}
n _{48V Telecommunication Isolated Power Supplies}
Description
The LT^®3753 is a current mode PWM controller optimized
for an active clamp forward converter topology, allowing
up to 100V input operation.
A programmable volt-second clamp allows primary switch
duty cycles above 50% for high switch, transformer and
rectifier utilization. Active clamp control reduces switch
voltage stress and increases efficiency. A synchronous
output is available for controlling secondary side syn-
chronous rectification.
The LT3753 is available in a 38-lead plastic TSSOP pack-
age with missing pins for high voltage spacings.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Typical Application
V_IN
36V TO 72V
4.7µF
100V
×3
105k
1.96k
1.87k
36V to 72V, 5V/20A Active Clamp Isolated Forward Converter
100nF
9:2
••
250V
0.22µF
200Ω
IRF6217
68nF
250V
5Ω
5Ω
BSC0902NSI
3.3µH
V_IN
SYNC
UVLO_V_SEC
OVLO
GND
14.7k
44.2k
AOUT
LT3753
30.1k
22nF
57.6k
1µF
10k
OUT
OC
I_SENSEP
I_SENSEN
SOUT
INTV_CC
BSC190N15NS3
BSC0902NSI
1k
0.012Ω
100Ω
4.7µF
25V
1µF
4.7nF
1k
22µF
10V
PS2801-1
100k
100k
1k
2.2nF
250V
100Ω
V_OUT
1µF
10V
V⁺
LT1431
GND-F _REF
GND-S
COLL
3.3nF ^34.8k
For more information www.linear.com/LT3753
V_OUT
5V
+ ^20A
560µF
10V
47µF
10V
137k
137k
3753 TA01
3753f
1