CM9320 Datasheet, PDF (6/10 Pages) California Micro Devices Corp – Asymmetrical High Efficiency Two Channel Boost LED Driver

Functional Block Diagram
PRELIMINARY
CM9320
V IN
EN
ISET1
ISET2
UVLO
BIAS
BG
OSC
PMW
LOGIC
OVP
D4
ENABLE
D1
Q1
CONTROL
D2
Q2
VOUT
SW
Q4
R
L E D1
L E D2
GND
CM9320
Pin Descriptions
LEAD(s)
1
2
3
4
5
6
7
8
9
NAME
ISET1
LED1
NC
ISET2
LED2
VIN
GND
SW
VOUT
PIN DESCRIPTIONS
DESCRIPTION
Channel 1 LED current set pin. Between this pin and GND connect the R_SET1 resistor, calcu-
lated as follows:
R_SET1(kΩ) = _I---L---_E---_D--4--₁-5--₍-0-m-----A-----₎
where I_LED1 is the DC LED current in channel 1.
Pin to cathode of channel 1 LED string.
Not internally connected. For better heat flow, connect to GND.
Channel 2 LED current set pin. Between this pin and GND connect the R_SET2 resistor, calcu-
lated as follows:
R_SET2(kΩ)
=
-----------4---5---0-----------
I_LED2(mA)
where I_LED2 is the DC LED current in channel 2.
Pin to cathode of channel 2 LED string.
Input supply voltage pin. Bypass with a 10µF or larger ceramic capacitor to ground.
Ground terminal pin.
Switching node. Internally connected to the drain of the integrated switch.
Output voltage pin, which connects to the anodes of all LEDs. Bypass with a 1.0µF or greater
ceramic capacitor to ground for low output ripple voltage.
© 2006 California Micro Devices Corp. All rights reserved.
6 490 N. McCarthy Blvd., Milpitas, CA 95035-5112 l Tel: [phone] l Fax: [phone] l www.cmd.com
05/08/06