CIRCUIT FOR THE OPERATION OF LIGHT SOURCES

摘要

An electronic transformer for halogen incandescent lamps is equipped with a self-commutated half-bridge inverter. The half-bridge inverter contains a start circuit with a start capacitor (C3), which starts commutation of the half-bridge inverter after each mains half-wave by driving a lower half-bridge transistor (T2). The start circuit has to be suppressed while the half-bridge inverter is commutating. This is achieved according to the invention by discharging the start capacitor (C3) when-ever an upper half-bridge transistor is turned on (T1). This is done by an amplifier element (V1), which is driven via a high-pass filter (C4) from the half-bridge midpoint (M).