CM9142 Datasheet, PDF (5/14 Pages) California Micro Devices Corp – Two Group, 4 and 2, WLED Driver, Different Current Settings

Functional Block Diagram
C1P C1N C2P C2N
PRELIMINARY
CM9142
Charge Pump x1, x1.5
VOUT
VIN
OSC
500 kHz
UVLO
Bandgap
Mode Select
Failed LED
EN
Condition
CM9142
Current
Sinks
LED1
LED2
LED3
LED4
LED5
LED6
GND
ISET1 ISET2
Pin Descriptions
LEAD(s)
1
2
3
4
NAME
LED1
C1P
VIN
ISET1
PIN DESCRIPTIONS
DESCRIPTION
Cathode of LED1 pin.
This pin is the plus side of charge pump bucket capacitor C1. Connect a 1.0μF
ceramic capacitor with a voltage rating of 10V or greater between C1N and C1P.
Positive supply voltage input pin. This voltage should be between 2.9V and 6V.
This pin requires a 1.0μF or larger ceramic capacitor to ground.
Current set and shutdown pin for drivers, active low.Pull high to shutdown the
group.
To set the LED current, a resistor, R_SET, is connected between this pin and ground.
The regulated LED current is 1000x the current flowing in R_SET, and is
approximately:
I_LED
=
0----.-6---6---V------–-----(_{--L----o----g---i--c---L----o---w-----}) _{× 1000}
R_SET
If this resistor is tied to directly ground (and enable function not used) Logic Low =
0, otherwise subtract the voltage drop of the device that drives this pin low.
© 2006 California Micro Devices Corp. All rights reserved.
04/26/06 490 N. McCarthy Blvd., Milpitas, CA 95035-5112 l Tel: [phone] l Fax: [phone] l www.cmd.com
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