Method of delaying and sequencing the starting of inverters that ballast lamps

摘要

An inverter circuit for ballasting a gas discharge lamp having a delay circuit designed to delay regenerative control of the inverter switches until a d.c. bus has attained steady-state operating d.c. voltage. The inverter circuit includes a drive control circuit for inducing an a.c. load current. The inverter circuit includes first and second complementary switches serially connected between the bus and a reference bus. The switches are connected together at a common node through which the a.c. load current flows. A driving inductor is connected at one end to the common node and operatively connected at the remaining end to a control node. A load circuit includes a resonant inductor connected at one end to the common node, with the resonant inductor mutually coupled to the driving inductor. A resonant capacitor is serially connected between the remaining end of the resonant inductor and the reference bus. The gas discharge lamp is serially connected with a d.c. blocking capacitor across the resonant capacitor. A delay circuit, comprising a serially connected resistor and capacitor is connected across the drive control circuit.