Abstract: A circuit arrangement for supplying a load which comprises a discharge lamp. The circuit includes apparatus for generating a DC voltage and provided with input terminals for connection to a supply voltage source. A rectifier is coupled to the input terminals for rectifying an AC voltage supplied by the supply voltage source. In addition, there are output terminals for connection to the load and a DC-DC converter connected between the rectifier and the output terminals and provided with a first inductor, a first unidirectional element, and a switching element. The output terminals are interconnected by a circuit branch which comprises a series arrangement of an impedance and a first capacitor, which impedance is shunted by a further unidirectional element. As a result, the inrush current which flows immediately after switching-on of the circuit arrangement is limited.

Abstract: A transient voltage protection circuit for operating a lamp includes input terminals for connection to a supply voltage source which delivers a low-frequency AC voltage. A rectifier is coupled to the input terminals for rectifying the low-frequency AC voltage and has output terminals. A first branch comprising a series arrangement of a breakdown element and a first capacitor interconnects the output terminals and a second branch shunts the first capacitor for discharging the first capacitor. A further capacitor, across which a DC voltage is present during lamp operation, supplies an operating voltage to the lamp. A DC--DC converter is coupled to the output terminals and to the further capacitor and a third branch comprising a series arrangement of a diode and the further capacitor shunts the first capacitor.