Patent ID: 7355354
Filing Date: 2008-04-08
Classification: H05B,Y02B

Abstract:
1. Apparatus for driving a lamp, comprising: (a) a plurality of MOSFET switches arranged in an H-bridge network for generating an AC signal from a DC signal coupled to the network of the plurality of switches, the AC signal being generated by a portion of the network of the plurality of switches periodically opening and closing opposite to the periodic opening and closing of another portion of the network of the plurality of switches; (b) a filter coupled between the network of the plurality of switches and the lamp, to filter the AC signal delivered to the lamp; (c) a controller for periodically opening and closing portions of the network of the plurality of switches based on a resonant frequency of the filter, so that the optimal amount of electrical power is provided for driving the lamp under a range of voltages provided by the DC signal, the controller also providing a higher energy pulse during striking of the lamp; (d) a plurality of gate drivers that receive signals from the controller, each gate driver associated with a respective MOSFET in the H-bridge network and each gate driver providing amplification of logic signals that control the operation of the associated MOSFET; and (e) a capacitor coupled at one end to an output terminal of the H-bridge network and the load and coupled at the other end to a diode that is in turn coupled to a voltage reference, the capacitor enabling a turn on voltage to be applied to a gate of an upper MOSFET when the voltage at a source of the upper MOSFET is approximately equal to a rail of a power supply.