RT9378 Datasheet, PDF (1/10 Pages) Richtek Technology Corporation – 4 CHs 100mA x1/x1.5/x2 Charge Pump White LED Driver

RT9378
4 CHs 100mA x1/x1.5/x2 Charge Pump White LED Driver
General Description
The RT9378 is a 4 CH WLED driver with auto mode
selection of x1, x1.5 and x2 mode with low dropout voltage
in current sources. The RT9378 can power up to 4 white
LEDs with regulated constant current for uniform intensity.
Each channel (LED1 to LED4) can support up to 25mA.
The part maintains highest efficiency by utilizing x1/x1.5/
x2 fractional charge pump and low dropout current
regulators. For the brightness control, user can easily use
a PWM signal generated from GPIO to control the
brightness of WLEDs.
The RT9378 is available in a WQFN-12L 2x2 package.
Small 0.22μF capacitors can be used for fly capacitors. It
provides the best backlighting solution with high efficiency
and smallest board space for portable application.
Ordering Information
RT9378
Package Type
QW : WQFN-12L 2x2
Lead Plating System
G : Green (Halogen Free and Pb Free)
Note :
Richtek products are :
` RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
` Suitable for use in SnPb or Pb-free soldering processes.
Typical Application Circuit
C_FLY1
0.22µF
C_FLY2
0.22µF
V_IN
2.8V to 4.5V
PWM Dimming
3
C1P
5 _VIN
C_IN
1µF
6 _EN
2, Exposed pad (13) _GND
1 4 12
C1N C2P C2N
RT9378
LED1 ⁷
LED2 ⁸
LED3 ⁹
LED4 ¹⁰
VOUT ¹¹
C_OUT
1µF
Features
z Efficiency Up to 93% Over Li-ion Battery Discharge
z Typical 85% Average Efficiency Over Li-ion Battery
Discharge
z Support Up to 4 White LEDs
z Support Up to 25mA/Per Channel
z Support Up to 100mA Output Current
z PWM Brightness Control
z 60mV Typical Current Source Dropout
z 1% Typical LED Current Accuracy
z 0.7% Typical LED Current Matching
z Automatic x1/x1.5/x2 Charge Pump Mode
Transition
z Low Input Noise and EMI Charge Pump
z 5V Over Voltage Protection
z Power On/Mode Transition In-rush Protection
z 1MHz Switching Frequency
z 0.4μA Low Shutdown Current
z RoHS Compliant and Halogen Free
Applications
z Camera Phone, Smart Phone
z White LED Backlighting
Pin Configurations
(TOP VIEW)
12 11 10
C1N 1
9 LED3
GND 2
C1P 3
GND 8 LED2
13 _{7 LED1}
456
WQFN-12L 2x2
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
DS9378-03 April 2011
www.richtek.com
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