Patent Number: 6,166,494

Title: Drive circuit arrangement for a gas discharge lamp

Abstract: A drive circuit arrangement for a gas discharge lamp includes a) a self resonating inverting for providing a drive voltage across a load impedance, the inverter having a pair of field effect transistors which operate in anti-phase, b) a tank circuit for canceling the reactive component of the load impedance coupled to the inverter, c) a voltage division circuit which provides a given fraction of the drive voltage to the gates of the field effect transistors, and d) a phase shifting means comprising an inductance in series with the tank circuit for shifting the phase of the given fraction of the drive voltage. The voltage division circuit is provided with a voltage limiter which in operation provides a further phase shift to the given fraction of the drive voltage when the drive voltage exceeds a given threshold value, increasing the resonant frequency of the inverter and limiting the peak drive voltage.

Inventors: Green; Ian Macdonald (London, GB)

Assignee: Central Research Labs, Ltd.

International Classification: H05B 41/282 (20060101); H05B 41/28 (20060101); H05B 037/02 ()

Expiration Date: 12/26/2017