LT3585-2_15 Datasheet, PDF (1/20 Pages) Linear Technology – Photofl ash Chargers with Adjustable Input Current and IGBT Drivers

FEATURES
■ _{Adjustable Input Current}
■ _{Integrated IGBT Driver}
■ _{No Output Voltage Divider Needed}
■ _{Uses Small Transformers: 5.8mm × 5.8mm × 3mm}
■ _{Fast Photoflash Charge Times}
■ _{Charges Any Size Photoflash Capacitor}
■ _{Supports Operation from Single Li-Ion Cell, Two AA}
Cells or any Supply from 1.5V Up to 16V
■ _{Small 10-Lead (3mm × 2mm) DFN Package}
Fast Charge Time
VERSION
NORMAL MODE
INPUT
CHARGE TIME
CURRENT (mA)
(Sec)
LT3585-3
800/400
3.3
LT3585-0
550/275
4.6
LT3585-2
400/200
5.8
LT3585-1*
250/115
5.0
100µF capacitor, 320V, V_IN = V_BAT = 3.6V
*50µF capacitor, 320V, V_IN = V_BAT = 3.6V
U
APPLICATIO S
REDUCED MODE
CHARGE TIME
(Sec)
6.6
9.2
12.6
14.6
■ _{Digital/Film Camera Flash}
■ _{PDA/Cell Phone Flash}
■ _{Emergency Strobe}
LT3585-0/LT3585-1
LT3585-2/LT3585-3
Photoflash Chargers with
Adjustable Input Current
and IGBT Drivers
DESCRIPTIO
The LT^®3585 series are highly integrated ICs designed to
charge photoflash capacitors in digital and film cameras.
A new control technique allows for the use of extremely
small transformers. Each part contains an on-chip high
voltage NPN power switch. Output voltage detection is
completely contained within the part, eliminating the need
for any discrete zener diodes or resistors. The output volt-
age can be adjusted by simply changing the turns ratio
of the transformer.
The CHRG/IADJ pin gives full control of the part to the
user. Driving CHRG/IADJ low puts the part in low power
shutdown. The CHRG/IADJ pin can also be used to reduce
the input current of the charger, useful in extending battery
life. The DONE pin indicates when the part has completed
charging.
The LT3585 series of parts are housed in tiny 3mm ×
2mm DFN packages.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATIO
LT3585-1 Photoflash Charger Uses High Efficiency
2mm Tall Transformers with Tunable IGBT Gate Drive
DANGER HIGH VOLTAGE! OPERATION BY HIGH VOLTAGE TRAINED PERSONNEL ONLY
V_BAT
2 AA OR
1 TO 2 Li-Ion
4.7µF
1:10:2
1_• 4
2 ^•5
V_BAT
DONE
SW
GND
CHRG/IADJ
V_IN
5V
V_IN ^LT3585-1
0.22µF _IGBTPWR
IGBTIN IGBTPU
IGBTPD
20Ω TO
160Ω
320V
+ 50µF
PHOTOFLASH
CAPACITOR
TO GATE OF IGBT
1M
2.2µF
600V
TRIGGER T
1
3
2
A
FLASHLAMP
C
3585 TA01a
LT3585-1 Charging Waveform
Normal Input Current Mode
V_OUT
50V/DIV
I_IN
500mA/DIV
V_BAT = 3.6V
C_OUT = 50µF
1sec/DIV
3585 TA01b
3585f
1