Datasheet

FUNCTIONAL DEVICE OPERATION
LIGHTING SYSTEM
Analog Integrated Circuit Device Data
114 Freescale Semiconductor
MC13892
LIGHTING SYSTEM
The lighting system includes backlight drivers for main display, auxiliary display, and keypad. The backlight LEDs are
configured in series. Three additional drivers are provided for RGB or general purpose signaling.
BACKLIGHT DRIVERS
The backlight drivers LEDMD, LEDAD and LEDKP are independent current sink channels. Each driver channel features
programmable current levels via LEDx[2:0] as well as programmable PWM duty cycle settings with LEDxDC[5:0]. By a
combination of level and PWM settings, the backlight intensity can be adjusted, or a soft start and dimming feature can be
implemented. The on period of the serial LED backlight drivers will be adapted to take into account that the serial LED switcher
startup time is longer than one half the minimum of the period of the backlight drivers.
When applying a duty cycle of less than 100% the backlight drivers will be turned on and off at a repetition rate high enough
to avoid flickering and or beat frequencies with the different types of displays. Also, to avoid high frequency spur coupling in the
application, the switching edges of the output drivers are softened.
The current level is programmable in a low range mode and in a high range mode through the LEDxHI bit. This facilitates the
current setting, in case two or more serial LED strings are connected in parallel to the same driver or when using super bright
LEDs.
Table 103. USB OTG Specifications
Parameter Condition Min Typ Max Units
VBUS Input Impedance As A_device
40 - 100 kΩ
UID 220K Pull-up
(89)
IDPUCNTRL = 0, Resistor to VCORE
132 220 308 kΩ
UID Pull-up
(89)
IDPUCNTRL = 1, Current source from VCORE
4.75 5.0 5.25 μA
UID Parallel Pull-up
(89)
ID100KPU = 1, Resistor to VCORE
60 100 140 kΩ
Notes
89. Note that the UID Pull-ups are not mutually exclusive of each other; they are independently controlled by their enable bits and thus
multiple pull-ups can be engaged simultaneously.
Table 104. Backlight Drivers Current Programming
LEDx[2:0]
(90)
LEDx Current Level (mA)
LEDxHI = 0 LEDxHI = 1
000 0 0
001 3 6
010 6 12
011 9 18
100 12 24
101 15 30
110 18 36
111 21 42
Notes
90. “x Represents MD, AD and KP