SNVA958 April 2020 LP8863-Q1
The LP8863-Q1 device uses the LEDx pin voltage to detect the string configuration. If the device powered off then on immediately, the boost output is not fully discharged, causing LEDx pin is not fully discharged, the string auto-detection may work improperly like Application Issue 1.
For example, if power off then on immediately, the 6 separate strings mode could be detected as all outputs connected together mode (AUTO_LED_STRING_CFG = 7h) since all LEDx pin voltage is beyond 1 V, as shown in Figure 4(a) and Figure 4(b). There will be no phase shift but should be 60°. For the solution, see Section 3.3.
|(a) LP8863-Q1 String Detection Flow|
|(b) LED String Detection Waveform|