LT3484-1_15 Datasheet, PDF (1/12 Pages) Linear Technology – Photoflash Capacitor Chargers

LT3484-0/LT3484-1/LT3484-2
Photoflash Capacitor
Chargers
FEATURES
■ _{Highly Integrated IC in 2mm × 3mm DFN Package}
Reduces Solution Size
■ _{Uses Small Transformers:}
5.8mm × 5.8mm × 3mm
■ _{Fast Photoflash Charge Times:}
4.6s for LT3484-0 (0V to 320V, 100µF, V_IN = 3.6V)
5.7s for LT3484-2 (0V to 320V, 100µF, V_IN = 3.6V)
5.5s for LT3484-1 (0V to 320V, 50µF, V_IN = 3.6V)
■ _{Operates from Two AA Batteries, or Any Supply from}
1.8V up to 16V
■ _{Controlled Average Input Current}
500mA (LT3484-0)
350mA (LT3484-2)
225mA (LT3484-1)
■ _{No Output Voltage Divider Needed}
■ _{No External Schottky Diode Required}
■ _{Charges Any Size Photoflash Capacitor}
■ _{Available in 6-Lead 2mm × 3mm DFN Package}
U
APPLICATIO S
■ _{Digital Camera and Cell Phone Flash Charger}
DESCRIPTIO
The LT^®3484 family of photoflash capacitor charger ICs is
designed for use in digital camera and mobile phone
applications where space is at a premium. The LT3484’s
patented control technique allows it to use extremely small
transformers, and the improved NPN power switch re-
quires no external Schottky diode clamp, reducing solu-
tion size. Output voltage detection requires no external
circuitry as the transformer turns ratio determines final
charge voltage.
The devices feature a V_BAT pin, which allows the use of 2
alkaline cells to charge the capacitor. The LT3484-0, -2
and -1 have primary current limits of 1.4A, 1A and 0.7A
respectively, resulting in tightly controlled average input
current of 500mA, 350mA and 225mA respectively. The
three versions are otherwise identical.
The CHARGE pin gives full control of the part to the user.
Driving CHARGE low puts the part in shutdown. The DONE
pin indicates when the part has completed charging. The
LT3484 series of parts are housed in a tiny low profile
2mm × 3mm DFN package.
, 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 6636021.
TYPICAL APPLICATIO
LT3484-0 Photoflash Charger Uses
High Efficiency 3mm Tall Transformers
DANGER HIGH VOLTAGE – OPERATION BY HIGH VOLTAGE
TRAINED PERSONNEL ONLY
V_BAT
2AA OR
1 TO 2 Li-Ion
4.7µF
1:10.2
1
4
2
5
V_BAT
SW
V_CC
5V
V_IN
0.1µF
100k
LT3484-0
GND
320V
+ _150µF
PHOTOFLASH
CAPACITOR
DONE
CHARGE
348412 TA01
LT3484-0 Charging Waveform
V_IN = 3.6V
C_OUT = 100µF
V_OUT
50V/DIV
AVERAGE
INPUT
CURRENT
1A/DIV
1s/DIV
3484 TA02
3484012f
1