Control and protective circuit for e.g. high intensity discharge lamp, has comparator provided for producing impulse signals, and pulse width modulation circuit provided for controlling output power of fluorescent tube

摘要

The circuit has four comparators (CA1-CA4), a timer (T), and a pulse width modulation circuit (P), where a comparator is provided for producing impulse signals. Another comparator is provided for lighting condition of a high intensity discharge lamp. A third comparator detects low voltage and short-circuits of a fluorescent tube. A fourth comparator detects overvoltage of the tube. The timer is provided for protection during no-load operation and discharge of the tube. The modulation circuit is provided for controlling an output power of the tube.