DRIVE CIRCUIT FOR DRIVING A GAS DISCHARGE LAMP, AND METHOD OF CALIBRATING A DRIVE CIRCUIT

摘要

A method is described for calibrating a CDCCD circuit (100) comprising: first and second voltage input terminals (101, 102); first and second switching bridges, each comprising two controllable switches connected in series between said first and second input terminals; a series arrangement of a first inductor (131), load output terminals (191, 192), and a second inductor (132) coupled between bridge output nodes (113, 123); a current sensor (150) associated with said first inductor (131); a reference signal generator (160); a switch controller (170) receiving a measuring signal (S 1) from the current sensor and a reference signal (SR) from the reference signal generator; the method comprising the steps of: generating an AC current having a zero DC level; measuring a voltage at an output terminal; adjusting the current reference signal in such a way that the measured voltage is symmetrical with respect to the input voltage levels.