LT3750 Datasheet, PDF (1/16 Pages) Linear Technology – Capacitor Charger Controller

FEATURES
■ _{Charges Any Size Capacitor}
■ _{Easily Adjustable Output Voltage}
■ _{Drives High Current NMOS FETs}
■ _{Primary-Side Sense—No Output Voltage Divider}
Necessary
■ _{Wide Input Range: 3V to 24V}
■ _{Drives Gate to VCC – 2V}
■ _{Available in 10-Lead MS Package}
U
APPLICATIO S
■ _{Emergency Warning Beacons}
■ _{Professional Photoflash Systems}
■ _{Security/Inventory Control Systems}
■ _{High Voltage Power Supply}
■ _{Electric Fences}
■ _Detonators
LT3750
Capacitor Charger
Controller
DESCRIPTIO
The LT^®3750 is a flyback converter designed to rapidly
charge large capacitors to a user-adjustable target volt-
age. A patented boundary mode control scheme* mini-
mizes transition losses and reduces transformer size. The
transformer turns ratio and two external resistors easily
adjust the output voltage.* A low 78mV current sense
accurately limits peak switch current and also helps to
maximize efficiency. With a wide input voltage range, the
LT3750 can operate from a variety of power sources. A
typical application can charge a 100µF capacitor to 300V
in less than 300ms.
The CHARGE pin gives full control of the LT3750 to the
user. The DONE pin indicates when the capacitor has
reached its programmed value and the part has stopped
charging.
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
*Protected by U.S. Patents, including 6518733, 6636021.
TYPICAL APPLICATIO
300V, 6A Capacitor Charger
V_TRANS
V_CC
12V
10µF
10µF
V_CC
100k
V_TRANS
RV_OUT
DONE
RDCM
LT3750
OFF ON CHARGE
GATE
T1 _D1
1:10
56µF
×2
•₊
•
60.4k
43k
M1
V_OUT
300V
100µF
SOURCE
GND RBG
2.49k
12mΩ
100pF
3750 TA01a
6A Charge Time
300
V_TRANS = 18V
250
200
V_TRANS = 6V
V_TRANS = 12V
150
100
50
0
0
0.1
0.2
0.3
0.4
0.5
TIME (SECONDS)
3750 TA03c
3750fa
1