LP39542 Datasheet, PDF (27/58 Pages) National Semiconductor (TI) – Advanced Lighting Management Unit

FADE IN / FADE OUT
LP39542 has an automatic fade in and out for main and sub
backlight. The fade function is enabled to main and sub back-
lights with EN_FADE_W1_4 and EN_FADE_W5_6 register
bits. Register bits SLOPE_W1_4 and SLOPE_W5_6 set the
WLED dimming, SLOPE=0
slope of the fade curve. The fading times are shown in the
graphs, which corresponds the full range current change
(0-255). Note that when large display mode is selected (DIS-
PL = 1), then EN_FADE_W5_6 and SLOPE_W5_6 bits do not
have any effect.
WLED dimming, SLOPE=1
30008539
Name
SLOPE_W5_6
SLOPE_W1_4
EN_FADE_W5_6
EN_FADE_W1_4
DISPL
EN_W1_4
EN_W5_6
WLED Control Register (08H):
Bit
Description
Slope for WLED5-6
6 0 = Full range fade execution time 1.30s
1 = Full range fade execution time 0.65s
Slope for WLED1-4
5 0 = Full range fade execution time 1.30s
1 = Full range fade execution time 0.65s
Enable fade for WLED5-6
4 0 = Fade disabled
1 = Fade enabled
Enable fade for WLED1-4
3 0 = Fade disabled
1 = Fade enabled
Large display mode enable
0 = WLED1-4 and WLED5-6 are controlled
2 separately
1 = WLED1-4 and WLED5-6 are controlled with
WLED1-4 controls
Enable WLED1-4
1 0 = WLED1-4 disabled
1 = WLED1-4 enabled
Enable WLED5-6
0 0 = WLED5-6 disabled
1 = WLED5-6 enabled
30008540
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