ZHCSK37 August 2019 LP8867C-Q1 , LP8869C-Q1
PRODUCTION DATA.
When LED string voltage can be above or below VIN voltage, SEPIC configuration can be used. In this example, two separate coils or coupled coil could both be used for SEPIC. Separate coils can enable lower height external components to be used, compared to a coupled coil solution. On the other hand, coupled coil typically maximizes the efficiency. Also, in this example, an external clock is used to synchronize SEPIC switching frequency. External clock input can be modulated to spread switching frequency spectrum.