Patent ID: 6310790
Filing Date: 2001-10-30
Classification: H05B,Y02B

Abstract:
A circuit arrangement for supplying a direct current or a low-frequency commutated direct current to a lamp, comprising:supply input terminals for connection to the poles of a supply voltage source supplying an alternating current,rectifier means coupled to the supply input terminals to rectify the alternating current and provided with a first output terminal and a second output terminal,a buffer capacitance coupled to the output terminals of the rectifier means,a DC-DC converter of the downconverter type coupled to the buffer capacitance and provided witha first chain coupled to the output terminals and comprises a series-arrangement of a first circuit element and a first unidirectional element,a first control circuit coupled to the first circuit element to render the first circuit element high-frequency conducting and non-conducting at a frequency f1,a second chain coupled across the first unidirectional element and comprises a series arrangement of a first inductive element and a first capacitance, characterized in that the circuit arrangement is also provided witha third chain which comprises a second circuit element and which shunts the first unidirectional element,a second control circuit which is coupled to a control electrode of the second circuit element and which serves to render the second circuit element high-frequency conducting and non-conducting at a frequency f1,a fourth chain which shunts the first circuit element and which comprises a series arrangement of a second capacitance and a second unidirectional element, a junction point of the second capacitance and a first terminal of the second unidirectional element being coupled to the first output terminal of the rectifier means wherein a second terminal of the second unidirectional element is coupled to the first chain, and the circuit arrangement includesa lamp connection terminal connected so that a direct current is made to flow through a lamp when connected to said lamp connection terminal.