LT3752-1_15 Datasheet, PDF (1/52 Pages) Linear Technology – Active Clamp Synchronous Forward Controllers with Internal Housekeeping Controller

LT3752/LT3752-1
Active Clamp Synchronous
Forward Controllers with Internal
Housekeeping Controller
FEATURES
n _{Input Voltage Range: LT3752: 6.5V to 100V,}
LT3752-1:Limited Only by External Components
n _{Internal Housekeeping DC/DC Controller}
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 _{Offline and HV Car Battery Isolated Power Supplies}
n _{48V Telecommunication Isolated Power Supplies}
n _{Industrial, Automotive and Military Systems}
DESCRIPTION
The LT^®3752/LT3752-1 are current mode PWM controllers
optimized for an active clamp forward converter topology.
A DC/DC housekeeping controller is included for improved
efficiency and performance. The LT3752 allows operation
up to 100V input and the LT3752-1 is optimized for ap-
plications with input voltages greater than 100V.
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 LT3752/LT3752-1 are available in a 38-lead plastic
TSSOP package 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
18V TO 72V
4.7µF
100V
×3
100k
5.9k
1.82k
18V to 72V, 12V/12.5A, 150W Active Clamp Isolated Forward Converter
INTV_CC
2.2µF
••
•
ZVN4525E6
499Ω 0.15Ω
V_IN
HOUT HI_SENSE
SYNC
UVLO_V_SEC
OVLO
LT3752
GND
22.6k
49.9k
34k
7.32k
31.6k
71.5k
22nF
0.33µF
V_AUX
2.2µF
4:4
••
6.8µH
470µF ⁺
16V
V_OUT
12V
12.5A
100nF
15nF
Si2325DS
FDMS86101
BSC077N12NS3
22µF
16V
×2
AOUT
2.8k
22nF
10k
OUT
OC
I_SENSEP
I_SENSEN
SOUT
INTV_CC
HFB
2k
220pF
10k
BSC077N12NS3
V_AUX
100k
0.006Ω
••
INTV_CC
100Ω
V_IN
2.2µF
GND
PGOOD
SYNC
560Ω
V_AUX
3.16k
4.7µF
4.7µF
1.1k 1µF
100Ω 100Ω
LT8311
68pF
100k
FB
11.3k
220nF
499k
13.7k
68pF
4.7nF
3752 TA01
100k
100k
1.2k
2.2nF
EFFICIENCY: 94% AT 48V_IN/10A_OUT
For more information www.linear.com/LT3752
3752fb
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