SM8134A Datasheet, PDF (1/19 Pages) Nippon Precision Circuits Inc – White LED Driver IC

SM8134A
White LED Driver IC
OVERVIEW
The SM8134A is a charge pump type white LED driver. It can drive 1 to 4 backlight white LED connected in
parallel and 1 flash white LED, making the device ideal for camera-equipped cellular phones. The charge
pump switches between ×1 to ×1.5 boost mode in response to LED drive current requirements to extend bat-
tery life to the maximum. The boost switching occurs in response to the drive current of all the connected LED
and thus supports variations in LED forward-bias voltage drop (VF). Each LED drive current is controlled by a
5-channel LED drive current control circuit. The backlight LED drive current and ON/OFF control, and flash
LED drive current and ON/OFF control are all set by 3-wire serial interface data input. Also, an under voltage
lockout (UVLO) circuit is built-in to prevent incorrect operation when the battery voltage drops.
FEATURES
I Noise reduction due to charge pump boost circuit
I Automatic charge pump switching to conserve
power
I Drives 1 to 4 backlight white LED
(30mA/ch at maximum setting)
I Drives a flash white LED
(150mA at maximum setting)
I Backlight and flash white LED brightness
adjustment
I 3-wire serial input interface for all setting and
control
I Under voltage lockout (UVLO) circuit built-in
I Soft start circuit built-in
I Thermal protection circuit built-in
I Input voltage range
• No-load current (I_OUT = 0mA): 2.7 to 4.6V
• Load current (I_OUT = 80mA): 3.0 to 4.6V
• Load current (I_OUT = 180mA): 3.3 to 4.6V
• Load current (I_OUT = 200mA): 3.4 to 4.6V
I Quiescent current
• Not-switching (×1.0 mode): 0.3mA (typ)
• Switching (×1.5 mode): 1.7mA (typ)
I Standby current: 0.01µA (typ)
I Operating frequency: 750kHz (typ)
I Maximum backlight LED current: 30mA/ch
I Maximum flash LED current: 150mA
I All LED total maximum current: 200mA
I Backlight LED current matching (I_LED = 20mA)
: ± 3%
I Flash LED current accuracy (I_LED = 150mA)
: ± 6.7%
I Packages: 16-pin QFN
PINOUT
(Top view)
DIN3
DIN4
DIN5
PGND
SDA
DIN1
VOUT
VIN
PACKAGE DIMENSION
(Unit: mm)
TOP VIEW
3.0 ± 0.08
B
A
BOTTOM VIEW
1.8
0.2 S A B
S
0.2 S
0.05 S
0.5
APPLICATIONS
I Cellular phone
I Digital still camera
I PDA
I Portable games
C 0.3
0.22 ± 0.05 ∆ 0.05 M S A B
ORDERING INFORMATION
Device
SM8134AB
Package
16-pin QFN
SEIKO NPC CORPORATION —1