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BD9420F is high efficiency driver for white LED. This is designed for large sized LCD. BD9420F is built-in DCDC converter that supply appropriate voltage for light source. BD9420F is also built-in protection function for abnormal state such as OVP: over voltage protection, OCP: over current limit protection of DCDC, SCP: short circuit protection, open detection of LED string. Thus this is used for conditions of large output voltage and load conditions.