Datasheet

Input Data Code
(Decimal)
3/256
PWM dimming duty
4/256
5/256
0
6/256
3 2 4 1 5 254 253 255 252 0
256/256
251
255/256
254/256
253/256
252/256
(Skipped) 1/256
2/256
LM3463
www.ti.com SNVS807A –MAY 2012–REVISED MAY 2013
Figure 33. PWM dimming duty vs code value of a data byte
DC Interface Mode
Connecting the MODE pin to VCC enables DC interface mode. In this mode the LM3463 converts the voltage on
the dimming signal input pins into PWM dimming duty to the corresponding output channels. The six output
channels are separated into four individual groups to accept external PWM dimming signals as listed in the
following table:
Group A CH0 and CH1, controlled by the voltage at DIM01 pin
Group B CH2 and CH3, controlled by the voltage at DIM23 pin
Group C CH4, controlled by the voltage at DIM4 pin
Group D CH5, controlled by the voltage at DIM5 pin
In DC interface mode, the DIM01, DIM23, DIM4 and DIM5 pins accept DC voltages in the range of 0.8V to 5.7V
to facilitate PWM dimming control. The voltage at the DIMn pins (V
DIMn
) and the PWM dimming duty in the DC
interface mode (D
DC-DIM
) are governed by the following equation. Figure 34 shows the correlation of V
DIMn
and
D
DC-DIM
. The conversion characteristic is shown in Figure 35.
where
• 0.8V < V
DIMn
< 5.7V (14)
The PWM dimming frequency in the DC interface mode is defined by the system clock of the LM3463. The
dimming frequency in the DC interface mode is equal to the system clock frequency divided by 1280 which
follows the equation below:
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