Datasheet

Functional Description
MC13783 Technical Data, Rev. 3.5
46 Freescale Semiconductor
Figure 12. MC13783 Lighting System
4.5.2.1 Backlight Drivers
The backlight drivers are generally intended for White LED (WLED) backlighting of color LCD displays
or white/blue LED backlighting for key pads. The drivers consists of independently programmable current
sinking channels. SPI registers control programmable features such as DC current level, auto ramping /
dimming and PWM settings.
Three zones are provided for typical applications which may include backlighting a main display, auxiliary
display, and key pad. However, the drivers can be utilized for other lighting schemes such as an integrated
WLED flashlight or even non-LED system applications requiring programmable current sinks.
The integrated boost switcher provided on the MC13783 is used to supply the backlights. It automatically
adapts its output voltage to allow for power optimized biasing of white and/or blue LEDs. Alternatively,
any other available source with sufficient current drive and output voltage for necessary diode headroom
may be used (5.5 V should not be exceeded).
4.5.2.2 Tri-Color LED Drivers
The tri-color circuitry provides expanded capability for independent lighting control and distribution that
supplements the backlight drivers circuitry. The tri-color drivers have the same basic programmability as
the backlight drivers, with similar bit control for current level, duty cycle control, and ramping. A boosted
BOOST
Main
Display
A
ux
Display
BOOST
Key Pad
BOOST
B
P
BOOST
B
P
BOOST
B
P
Tri-Color Fun
Light Drive
L
E
D
R
1
L
E
D
B
1
L
E
D
G
1
L
E
D
M
D
1
G
N
D
L
E
D
B
L
G
N
D
L
E
D
T
C
L
E
D
M
D
2
L
E
D
M
D
3
L
E
D
M
D
4
L
E
D
A
D
1
L
E
D
A
D
2
L
E
D
K
P
L
E
D
R
2
L
E
D
B
2
L
E
D
G
2
L
E
D
R
3
L
E
D
B
3
L
E
D
G
3
BL Drive
Main Display
BL Drive
A
ux Displa
y
BL Drive
Keypad
MC13783 IC
Lighting System