MC13892JVLR2 Freescale, MC13892JVLR2 Datasheet - Page 115

• Manufacturer Part Number: MC13892JVLR2
• Manufacturer: Freescale

Specifications of MC13892JVLR2

• Operating Temperature (max): 85C
• Operating Temperature (min): -30C
• Mounting: Surface Mount
• Package Type: BGA
• Case Length: 12mm
• Screening Level: Commercial
• Lead Free Status / RoHS Status: Compliant

Table 106. Serial LED Driver Characteristics
time is therefore a function of the initial set PWM cycle and the final PWM cycle. As an example, starting from 0/32 and going to
32/32 will take 500 ms, while going to from 8/32 to 16/32 takes 125 ms. Note that the ramp function is executed upon every
change in PWM cycle setting when the corresponding LEDxRAMP = 1. If a PWM change is programmed via SPI when
LEDxRAMP = 0, then the change is immediate rather than spread out over a PWM sweep.
three backlight drivers are enabled through the LEDxEN bits, meaning none of the duty cycles equals 0/32, then none of the
drivers will be activated.
enabled and disabled in a 50/50 percent fashion at a sufficiently high rate. The LED drive current will automatically be doubled
to the same luminosity as in a single backlight driver configuration.
domain is represented by 3 ballasted stacks, that include 3 blue LEDs in each (a diagram of Serial LED configurations is included
later in this chapter).
Active" case shows the LEDMD zone driven at twice the current for half the time.
Notes
on a driver channel, ballasting resistance is recommended to help balance the currents in each leg.
Analog Integrated Circuit Device Data
Freescale Semiconductor
80.
Output Current Setting
Current Programming Granularity
PWM Granularity
Repetition Rate
Absolute Accuracy
Matching
Glow and Dimming Speed
The ramp itself is generated by increasing or decreasing the PWM duty cycle with a 1/32 step every 1/64 seconds. The ramp
A maximum of only two backlight drivers can be activated at the same time, for instance, the main display plus keypad. If all
If two backlight drivers are enabled, they time-share the external boost converter output. The drivers will automatically be
Figure 33
The "One Driver Active" case shows the general response when driving a single zone of 6 white LEDs. The "Two Drivers
Figure 34
Equivalent to 500 ms ramp time when going from 0/32 to 32/32
illustrates some possible configurations for the backlight driver. Note that when parallel strings are ganged together
illustrates the time sharing principle. Assume the MD domain is represented by 6 series white LEDs, and the KP
Parameter
(80)
External
LEDMD
Current
Current
Boost
LEDKP
Figure 33. Backlight Drivers Time Sharing Example
Low Range Mode
High Range Mode
Low Range Mode
High Range Mode
Not blinking
At 400 mV, 21 mA
Per 1/32 duty cycle step
One Driver
LEDMD
Active
Active
Condition
LEDMD
Active
LEDKP
Active
Two Drivers
Active
Min
LEDMD
0
0
Active
-
-
-
-
-
-
-
LEDKP
Active
1/64*
1/32
Typ
256
3.0
6.0
FUNCTIONAL DEVICE OPERATION
-
-
-
-
Max
3.0
15
30
15
-
-
-
-
-
LIGHTING SYSTEM
Units
mA
mA
Hz
%
%
S
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