Patent ID: 8659231
Filing Date: 2014-02-25
Classification: H05B,Y02B

Abstract:
1. An electronic ballast for operation of at least one discharge lamp, the electronic ballast comprising: an input comprising a first input connection and a second input connection for coupling to an AC supply voltage; a rectifier comprising an input and an output, with the input of the rectifier being coupled to the first input connection and the second input connection; an apparatus for power factor correction comprising an input and an output, with the input of the apparatus for power factor correction being coupled to the output of the rectifier, and with the apparatus for power factor correction comprising a voltage converter having an inductance, a diode and a switch in which case an intermediate-circuit voltage can be produced at the output of the apparatus for power factor correction during operation of the electronic ballast; a load circuit comprising a first output connection and a second output connection for coupling to the at least one discharge lamp, with the load circuit being coupled to the output of the apparatus for power factor correction; a control apparatus comprising an I regulator with a nominal value input and an actual value input, with the nominal value input being coupled to a nominal-value production apparatus for production of a variable which is correlated with the nominal value of the intermediate-circuit voltage, with the actual value input being coupled to a node of the load circuit for production of a variable which is correlated with the actual value of the intermediate-circuit voltage, with the control apparatus being designed to produce at its output a control signal to the switch of the voltage converter, with the control signal being a square-wave signal, with the controlled variable of the I regulator representing a first component of the on time of the control signal, with the on time representing the time duration within one period of the square-wave signal, within which the switch in the voltage converter is switched on; and a P regulator connected in parallel with the I regulator; wherein the P regulator is configured to produce a third component of the on time of the control signal; wherein the transfer function of the P regulator, which reproduces the relationship between the third component of the on time and a change in the intermediate-circuit voltage, has at least one section with a predeterminable gradient; and wherein the electronic ballast furthermore comprises a power determining apparatus, which is designed to determine a variable which is correlated with the power consumed in the discharge lamp during operation of the at least one discharge lamp, with the power determining apparatus being coupled to the control apparatus, and with the control apparatus being designed to vary the control signal as a function of the power consumed in the discharge lamp.