Circuit for operating a discharge lamp

摘要

The invention relates to a circuit for operating a discharge lamp (L). It contains a circuit part (ADD) which consists essentially of an operational amplifier (IC2-A), a current measuring resistor (R1) and a voltage divider (R2, R3), and is used for detecting the change in the instantaneous lamp power. The operational amplifier (IC2-A) carries out a desired-actual comparison of a first voltage drop (UP), which is formed additively from the voltage drop on the current measuring resistor (R1), which is proportional to the instantaneous lamp current, and from the voltage drop on the resistor (R2), which is proportional to the instantaneous lamp burning voltage, with a reference signal and passes its output signal to a control circuit (ST) which pulses the combinational circuit (SNT). The first voltage drop (UP) is proportional to the instantaneous lamp power at the operating point of the circuit. ……