Patent ID: 6366031
Filing Date: 2002-04-02
Classification: H05B,Y10S

Abstract:
An electronic ballast for at least one low-pressure discharge lamp comprising:an inverter arranged to be supplied with direct voltage and having an output which is connected to a load circuit containing terminal contacts for a lamp; a heating transformer having a primary winding, which is connected to said output of said inverter, a secondary winding of said heating transformer being connected in a heating circuit together with a coil for heating electrodes of a lamp; a series circuit connected in parallel with said load circuit, said series circuit including said primary winding of said heating transformer and electronic switch; an evaluating circuit connected to measure current flowing through said series circuit including said primary winding and said electronic switch; and said evaluating circuit being connected to additionally measure current flowing through said heating circuit and to evaluate the amplitude or the time characteristic of the measured current in order to identify the type of lamp and the state of the lamp.