LT3751_15 Datasheet, PDF (1/34 Pages) Linear Technology – High Voltage Capacitor Charger Controller with Regulation

LT3751
High Voltage Capacitor
Charger Controller with Regulation
Features
n _{Charges Any Size Capacitor}
n _{Low Noise Output in Voltage Regulation Mode}
n _{Stable Operation Under a No-Load Condition}
n _{Integrated 2A MOSFET Gate Driver with Rail-to-Rail}
Operation for V_CC ≤ 8V
n _{Selectable 5.6V or 10.5V Internal Gate Drive}
Voltage Clamp
n _{User-Selectable Over/Undervoltage Detect}
n _{Easily Adjustable Output Voltage}
n _{Primary or Secondary Side Output Voltage Sense}
n _{Wide Input VCC Voltage Range (5V to 24V)}
n _{Available in 20-Pin QFN 4mm × 5mm and 20-Lead}
TSSOP Packages
Applications
n _{High Voltage Regulated Supply}
n _{High Voltage Capacitor Charger}
n _{Professional Photoflash Systems}
n _{Emergency Strobe}
n _{Security/Inventory Control Systems}
n _Detonators
Description
The LT^®3751 is a high input voltage capable flyback con-
troller designed to rapidly charge a large capacitor to a
user-adjustable high target voltage set by the transformer
turns ratio and three external resistors. Optionally, a feed-
back pin can be used to provide a low noise high voltage
regulated output.
The LT3751 has an integrated rail-to-rail MOSFET gate
driver that allows for efficient operation down to 4.75V.
A low 106mV differential current sense threshold voltage
accurately limits the peak switch current. Added pro-
tection is provided via user-selectable overvoltage and
undervoltage lockouts for both V_CC and V_TRANS. A typical
application can charge a 1000µF capacitor to 500V in less
than one second.
The CHARGE pin is used to initiate a new charge cycle and
provides ON/OFF control. The DONE pin indicates when
the capacitor has reached its programmed value and the
part has stopped charging. The FAULT pin indicates when
the LT3751 has shut down due to either V_CC or V_TRANS
voltage exceeding the user-programmed supply tolerances.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property
of their respective owners. Protected by U.S. Patents including 6518733 and 6636021.
Typical Application
DANGER HIGH VOLTAGE! OPERATION BY HIGH VOLTAGE TRAINED PERSONNEL ONLY
V_TRANS
24V
+
330µF
×2
40.2k
T1
1:10
D1
10µF
×2
•
+
RV_TRANS
18.2k
•
OFF ON
CHARGE
RDCM
V_CC
24V
CLAMP
RV_OUT
V_{CC LT3751}
40.2k
10µF _TO
DONE
HVGATE
MICRO
FAULT
LVGATE
V_CC
374k
CSP
V_TRANS
UVLO1
475k
OVLO1
CSN
374k
UVLO2
V_{CC 475k}
FB
OVLO2
6mΩ
GND RBG
10nF
0.47µF
732Ω
500V
0 TO 150mA
100µF
715k
1.74k
3751 TA01a
Load Regulation and Efficiency
500
90
498
84
496
78
494
72
492
490
0
66
OUTPUT VOLTAGE
EFFICIENCY
60
50
100
150
LOAD CURRENT (mA)
3751 TA01b
3751fc
1