SGM3132 Datasheet, PDF (6/11 Pages) SG Micro Corp – Ultra Low Dropout Current Source

SGM3132
FUNCTION BLOCK DIAGRAM
4-Channel 1-Wire Dimming LED Driver
with Ultra Low Dropout Current Source
VIN
EN
GND
16 Steps Pulse
Dimming Controller
Shutdown Delay
Low Dropout
Current Source
LED1
LED2
LED3
LED4
APPLICATION INFORMATION
LED Connection
The SGM3132 supports up to 4 white LEDs. The four LEDs are connected from VIN to TQFN-3×3-16L package’s pin 10,
11, 12 and 13 respectively. For TDFN-2×2-8L and MSOP-8 packages, Cathode of white LEDs are connected to pin 5, 6,
7 and 8 respectively.
Brightness Control
The SGM3132 implements a pulse dimming method to control the brightness of white LEDs. Users can easily configure
the LED current from 1.25mA to 20mA by a serial pulse. The dimming of white LEDs' current can be achieved by
applying a pulse signal to the EN pin. There are totally 16 steps of current that could be set by users. The detail
operation of brightness dimming is showed in the Figure 1.
30μs < T_READY
0.5μs < T_HI
0.5μs < T_LO < 500μs
3ms < T_SHDN
EN
0
1
2
3
4
5
14
15
0
1
Shutdown
I_LEDx
100% _{15/16 14/16 13/16 12/16}
3/16
2/16
100%
1/16
15/16
Figure 1. Brightness Control by Pulse Dimming
Shutdown
SG Micro Corp
6
www.sg-micro.com