SLUSCZ1 May 2017 TPS92518-Q1
PRODUCTION DATA.
LED2_MAXOFF_DAC is shown in Figure 47 and described in Table 11.
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8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Reserved | LED2_MAXOFF_DAC | |||||||
R-0h | R/W-80h |
Bit | Field | Type | Reset | Description |
---|---|---|---|---|
8 | RSVD | R | 0 | Reserved |
7-0 | LED2_MAXOFF_DAC[7:0] | R/W | 80h |
Channel 2 maximum off time DAC value. |
LEDx_MAXOFF_DAC: the content of this register sets the maximum off-time for the corresponding channel, regardless of output voltage. LEDxMAXOFF and LEDx_TOFF operate in parallel. In normal operation, LEDxMAXOFF must always be longer in time than LEDxTOFF so as not to interfere with the normal operation of the converter.
The MaxOffTime value is most useful in LED Matrix or shunt-FET dimming applications. When the output LED voltage is sufficiently low (<2V), regular operation of the off-timer is not possible. This parallel timer does not rely on the output voltage and can be set to maintain consistent inductor current peak-to-peak ripple. Refer to the application section Off-Time Thresholds - LEDx_TOFF_DAC and LEDx_MAXOFF_DAC for equations to properly set the maximum off time under shunted conditions.
The Maximum off-time is also the time that must expire before the first cycle is initiated at start-up, or after a POR.