DISCHARGE LAMP ELECTRON BALLAST

摘要

A discharge lamp electron ballast includes a power conversion circuit having an inverter circuit and a resonance circuit, a drive circuit, a frequency control circuit, a prediction circuit, and a correction circuit. The inverter circuit applies a load voltage to a load circuit containing a lamp via the resonance circuit. The prediction circuit predicts a resonance frequency of a combination of the resonance circuit and the load circuit after lamp ignition. The resonance frequency is predicted according to an input signal expressing a load voltage in a period from the start of the inverter circuit operation frequency sweep to the moment immediately after the lamp ignition. A correction circuit modifies the end frequency of the sweep to the resonance frequency.