
United States Patents: 6,504,422, 6,794,926
www.semtech.com
1
POWER MANAGEMENT
Description
SC606
Low Noise Smart LED
Driver with Serial Interface
August 31, 2006
Applications
Features
The SC606 is a very high efficiency charge pump white/color LED
driver from the mAhXLife
TM
family of products. It is optimized for
Li-Ion battery applications. The LED current is regulated to a value
configured by the user through an I
2
C compatible serial interface.
LED outputs are current-matched for consistent LED brightness.
Up to 6 LEDs are controlled in three zones for brightness control in
multiple displays. The 6 LED outputs are divided into 3 pairs of
LEDs. Each pair has current that is programmable independent of
the serial interface. The SC606 also has a float detect feature
that disables any current driver during normal operation when an
open-load condition is detected.
Patented low noise switching circuitry and constant output current
allow the use of extremely small input and output capacitors.
Very High Efficiency Over 90% of Battery Life
Current Regulation for 6 LEDs
Current Matching Tolerance of +/- 3.5% from LED to LED
Current Accuracy to +/- 6.5% of Specified Value
Current Range per LED [0.5mA - 32mA]
High Available Total LED Current = 6 I
LED
= 120mA
I
2
C Bus Limited Compatibility SC606
Low Shutdown Current: 0.1
μ
A Typical
Soft-Start /In-rush Current Limiting
Short Circuit /Thermal Protection
MLP-16 [4x4] Package
1.33MHz and 250kHz Programmable Fixed Frequency
Separate Brightness Zones for Multiple Displays
Three Charge Pump Modes of Operation: 1x, 1.5x and 2x
Open LED Output Protection
Cellular Phones
LED Backlighting
PDA Power Supplies
Portable Devices
Electronic Books
Wireless Web Appliances
Typical Application Circuit
C3
1μF
C4
1μF
VBAT
1
2
3
4
5
6
7
8
9
10
SCL
SDA
EN
C2
1μF
V
V
C
C
C2-
C2+
GND
ILEDC2
ILEDA1
SDA
SCL
EN
I
I
I
I
D1
SC606
11
12
1
1
1
1
C1
1μF
D6
D5
D4
D3
D2
Patent Pending