Patent ID: 7629774

Claim:
Device for reducing the output current of a primary switched battery charger, which charger comprises an input DC power circuit, a high frequency transformer and a control unit for modulating the DC input power, said device comprising: a pulse measuring unit for measuring a pulse ratio of switch pulses on the output side of the charger; a peak measuring unit for measuring a peak value of an output voltage of the charger; a differential amplifying unit providing an output signal by differentially amplifying the measured pulse ratio of switch pulses from the pulse measuring unit and the measured peak value of the output voltage from the peak measuring unit; and an amplifier for adding the output voltage of the charger to the output signal from said differential amplifying unit, wherein the device is adapted to transmit the output signal from said amplifier to said control unit for use in modulating the input DC power in order to reduce the output current of the charger.