WHITE LED FLASHLIGHT DRIVER
GENERAL DESCRIPTION
ELM900x is a CMOS IC designed for driving white LEDs by one or two dry...
WHITE LED FLASHLIGHT DRIVER
GENERAL DESCRIPTION
ELM900x is a
CMOS IC designed for driving white LEDs by one or two dry cell as a power source. ELM900x can drive two series white LED by 1.5V-3.0V input
voltage. ELM900x uses an external inductor as a
voltage booster. ELM900x consists of an oscillator circuit and a driving transistor. The input DC power is transformed to a 35kHz constant current pulse, when the external inductor switched on and off in 35kHz. In a standard application inductor is needed as external parts.
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FEATURES
Low cost and simple application circuit High efficiency Constant average power control Low noise 35kHz constant frequency switching Compact SOT-89 package
APPLICATION
White LED flashlight Laser pointer High VF LED driver LCD backlighting
PIN CONFIGURATION
Pin No. Pin Name 1 VSS 2 VDD 3 LX
SOT-89
( TOP VIEW )
MARKING
: Represents the product IC code
90 : Represents the assembly lot number 0 9 repeated
: Represents the assembly lot number A Z repeated ( I,O,X excepted )
MARKING
Symbol './Z
293
WHITE LED FLASHLIGHT DRIVER ELM900x
BLOCK DIAGRAM
0EJ&TKXGT
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8&&
1%5
.:
855
APPLICATION CIRCUIT
2 cell 2LED
Ǵ*
9JKVG .'& 9JKVG .'&
8
'./Z
1 cell 1LED
Ǵ*
5K& 9JKVG .'&
8
'./Z
294
WHITE LED FLASHLIGHT DRIVER ELM900x
MAXIMUM ABSOLUTE RATINGS
Parameter Symbol Limit...
