SC668 Datasheet, PDF (43/46 Pages) Semtech Corporation – 8 LED Light Management Unit Automatic Dropout Prevention , Ambient Light Sense Input, PWM Dimming, and 4 LDOs

SC668
Register Map (continued)
ADP_RATE Bit D5
This bit sets the time that elapses before backlight current
reduces after ADP activates. A logic one delays reduction
of current for 4ms. A logic zero delays reduction of current
for 256µs.
OLE_EN2 through OLE_EN0 Bits [D3:D1]
These bits enable Other Lighting Effects (OLE), including
the auto-dim full and auto-dim partial, as shown in Table
25. Auto-dim functions are described in detail in the
Applications Information section.
When a reduction in bank #1 backlight current becomes
necessary, the first step change is delayed for 4ms (logic
one) or 256µs (logic zero). If bank #1 continues to need a
current reduction after the delay time has elapsed, the
brightness setting is lowered by one step. If further reduc-
tions in current are needed, the second and all subsequent
reductions occur at a faster rate equal to1/4 of the initial
delay time. Further reductions in current will stop when
the backlight accuracy and matching have normalized.
When 4ms is selected, the 1^st delay = 4ms, and the 2^nd and all
subsequent delays = 1ms. When 256μs is selected, the 1^st
delay = 256μs, and the 2^nd and all subsequent delays = 64μs.
Table 25 — OLE Bits
OLE_EN2 OLE_EN1 OLE_EN0
Lighting Effect
0
0
0
Reserved (no effects)
0
0
1
Auto-dim full (group #1)
0
1
0
Auto-dim partial (group #1)
0
1
1
1
0
0
1
0
1
Reserved (no effects)
1
1
0
1
1
1
ADP_EN Bit D4
This bit enables the ADP function. ADP is enabled when
this bit is a logic one. ADP is disabled when this bit is a
logic zero.
PWM_BYP Bit D0
When this bit is a logic zero, the PWM pin functions nor-
mally. When this bit is a logic one, the PWM pin is disabled,
so that a high or low on the PWM pin has no effect.
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