United States Patents: 6,504,422, 6,794,926
www.semtech.com
1
POWER MANAGEMENT
SC606
Low Noise Smart LED
Driver with Serial Interface
Description
February 3, 2005
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 other pairs. Any combination of LEDs may be turned on using
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 is accurate to +/-6.5% of the specified value
Wide 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
A typical
Soft start / Inrush 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
1F
C4
1F
VBAT
1
2
3
4
5
6
7
8
9
10
SCL
SDA
EN
C2
1F
VOU
T
VIN
C1-
C1 +
C2-
C2+
GND
ILEDC2
ILEDA1
SDA
SCL
EN
IL
EDA
2
IL
EDB
2
IL
EDC1
IL
EDB
1
D1
SC606
11
12
13
14
15
16
C1
1F
D6
D5
D4
D3
D2
Patent Pending
3
2005 Semtech Corp.
www.semtech.com
POWER MANAGEMENT
SC606
Notes:
1) I
LEDn
= any LED's current from D1, D2, D3, D4, D5 and D6
2) Guaranteed by design
3) Maximum total of LED currents not to exceed 120mA
4) X = Don't care
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