8.3.3.1.1 Open Detect

The logic uses the LOW comparators and the requested boost voltage to detect the OPEN condition. If the logic is asking the boost for the maximum allowed voltage and a LOW comparator is asserted, then the OPEN bit is set in the STATUS register (ADDR = 02h). In normal operation, the adaptive headroom control loop raises the requested boost voltage when the LOW comparator is asserted. If it has raised it as high as it can and an LED string still needs more voltage, then it is assumed to be disconnected from the boost voltage (open or grounded). The actual boost voltage is not part of the OPEN condition decision; only the requested boost voltage and the LOW comparators.