D.C. ciruit for starting high pressure discharge lamp

Abstract

A circuit arrangement for igniting and operating a discharge lamp (La), provided with input terminals (K1,K2) for connection to a DC voltage source, a commutator (COM) coupled to the input terminals and provided with terminals (K3,K4) for connecting the discharge lamp (La), for cornmutating a current through the discharge lamp (La), a branch A which is conducting in both directions at least for alternating current, of which branch a first end is connected to an input terminal (K2) and a further end is connected to the commutator (COM), and which branch comprises an inductive element L shunted by a branch B which comprises a unidirectional element (D), a branch C which connects a further input terminal to the commutator (COM), and an ignition circuit (S) for igniting the discharge lamp. According to the invention, the unidirectional element (D)is so included in the branch B that the branch B conducts a current at least immediately after ignition of the discharge lamp (La). It is achieved thereby that a lamp operated by means of the circuit arrangement has good take-over properties. The invention relates to a circuit arrangement for igniting and operating a discharge lamp, provided with input terminal for connection to a DC voltage source, a commutator coupled to the input terminals and provided with terminals for connecting the discharge lamp, for commutating a current through the discharge lamp, a branch A which is conducting in both directions at least for alternating current, of which branch a first end is connected to an input terminal and a further end is connected to the commutator, and which branch comprises an inductive element L shunted by a branch B which comprises a unidirectional element, a branch C which connects a further input terminal to the commutator, and an ignition circuit for igniting the discharge lamp.

Dependencies are inferred from the claim text.