Patent ID: 6051938
Filing Date: 2000-04-18
Classification: H05B

Abstract:
A circuit arrangement for high-frequency operation of a discharge lamp, comprising:input terminals for connection to a low-frequency supply voltage source,low-frequency rectifying means (LR) for generating a DC voltage across first capacitive means from a low-frequency supply voltage delivered by the low-frequency supply voltage source,a DC/AC converter for generating a high-frequency AC voltage from the DC voltage,a load branch (B) comprising a series arrangement of inductive means, second capacitive means, and coupling means (T3, T4) for coupling the discharge lamp to the load branch, the load branch being coupled to the DC/AC converter,high-frequency rectifying means (HR) for converting the high-frequency voltage generated by the DC/AC converter into a DC voltage, which high-frequency rectifying means is coupled to the first capacitive means and to the load branch and comprises a series arrangement of first and second unidirectional means having the same orientation,control means (CR) for controlling a power consumed by the discharge lamp to a level which is dependent on a control signal (Sg) which is a measure for a desired lamp power,wherein the high-frequency rectifying means in addition comprises further control means (CR1) and a parallel branch including switching means, which parallel branch shunts at least one of the unidirectional means of the high-frequency rectifying means, and said further control means controls the switching means in a manner which is dependent on the control signal.