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LT3750

3750fa

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Professional Photoflash Systems

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Security/Inventory Control Systems

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High Voltage Power Supply

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Electric Fences

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Detonators

Capacitor Charger

Controller

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Charges Any Size Capacitor

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Easily Adjustable Output Voltage

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Drives High Current NMOS FETs

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Primary-Side Sense—No Output Voltage Divider

Necessary

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Wide Input Range: 3V to 24V

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Available in 10-Lead MS Package

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO

, 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.

The LT

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 100

µF 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.

DONE

CHARGE

RDCM

GATE

SOURCE

60.4k

T1

1:10

D1

300V

12V

•

•

100

µF

43k

12m

Ω

M1

3750 TA01a

LT3750

GND

RBG

100k

2.49k

100pF

OFF ON

10

µF

10

µF

56

µF

×2

+

300V, 6A Capacitor Charger

TIME (SECONDS)

0

0

50

100

150

200

250

300

0.1

0.2

0.3

0.4

3750 TA03c

0.5

6A Charge Time