High voltage LED driver delivers high efficiency benefits
The HV9805 driver includes a linear post regulator to provide a pure DC current drive, for flicker free light output. The linear post regulator also provides protection from line voltage transients.
HV9805 supports a simple and low cost driver circuit, which combines a PFC boost stage and a linear post regulator for regulating the LED current to a DC value. The boost stage employs the boundary conduction mode, with the output regulated for lowest overhead voltage at the linear regulator. The headroom voltage can be freely selected to optimize the efficiency of the post regulator or to minimize the cost or size of the bus capacitor.
The boost converter employs a cascode switch for high speed switching and convenient generation of the housekeeping (VDD) supply. The low voltage device of the cascode switch is integral to the HV9805 and is rated at a current of 1 A. VDD power is derived with high efficiency and without the need for extra components or magnetic windings.