Patent ID: 6091614
Filing Date: 2000-07-18
Classification: H02M,H05B,Y02B

Abstract:
An electric device to be supplied by an electric power source, comprising:a dc load;a rectifier and power converter circuit for converting ac or dc voltage and current from the power source to dc voltage and current supplied to the dc load, the rectifier and power converter circuit comprising a switching means through which said rectifier and power converter circuit is supplied with the ac or dc voltage and current from the power source;means for producing a voltage signal representative of the amplitude of the ac or dc voltage from the power source;a power factor controller for controlling the switching means of the rectifier and power converter circuit in view of supplying dc voltage and current to the dc load while maintaining the power factor of the electric device equal to or close to unity, the power factor controller comprising a voltage comparator means supplied with the voltage signal representative of the amplitude of the ac or dc voltage from the power source for enabling operation of the power factor controller as long as the ac or dc voltage from the power source has an amplitude higher than a first predetermined voltage threshold; anda voltage boosting circuit for raising the amplitude of the voltage signal supplied to the voltage comparator means when the ac or do voltage from the power source is lower than the first predetermined voltage threshold to thereby keep operation of the power factor controller enabled.