Electronic ballast for gas discharge lamp, has measuring device with ohmic resistor and rectifier for measuring current and providing current measured value, so that full bridge circuit is controlled by controller depending on value

摘要

The ballast has a full bridge circuit with four switching units (S1-S4) and a load circuit that is arranged in a centre branch of the bridge circuit. A controller (ST) controls the bridge circuit and determines an impedance/voltage of the load circuit, and a measuring device includes an ohmic resistor and a rectifier (GR). The device measures current by one of the units and provides a current measured value for the controller, so that the bridge circuit is controlled by the controller depending on the value such that a phase-shifted full-bridge is realized with resonance ignition. An independent claim is also included for a method for controlling an electronic ballast for a gas discharge lamp.