SNVSCC4 October 2023 LP5811
PRODUCTION DATA
The LP5811 integrates LED short detection (LSD) for the fault caused by any short LED. The threshold of LSD is able to configure from (0.35 × VOUT) V to (0.65 × VOUT) V by configuring lsd_threshold in Dev_config_12 register. To have enough detection time, LSD can only be performed when the PWM setting of this LED is above 25. If the voltage on the cathode of this LED is higher than the LSD threshold in continuously 3 cycles, LED short of this LED is reported to the corresponding LSD_status register.
The LSD flags can be cleared by writing 1h to lsd_clear in Fault_CLR register. If the LED short status is removed, the related lsd_status bit is set to 0 automatically.
The 'lsd_action' bit in Dev_config_12 register can determine the reaction once open fault is detected. When the 'lsd_action' bit is set to 1h, all LEDs are turned off which is called one fails all fail (OFAF) action, to prevent potential damage caused by the short issue. The device enters to STANDBY state after sending 'lsd_clear' command. When the 'lsd_action' bit is 0, no additional action is taken after LSD is detected. LSD detecion is only executed in NORMAL state.