POWER-SUPPLY CIRCUIT FOR AN ELECTRICAL APPLIANCE HAVING A BATTERY AND A DC-TO-DC CONVERTER

摘要

The invention relates to a supply voltage circuit for a small electrical appliance that contains a battery, an electric motor, a controllable switch, a control circuit and a DC-to-DC converter, wherein the electric motor is connected to the battery by means of the controllable switch and the DC-to-DC converter powers the control circuit from the battery. The control circuit controls the controllable switch in such a way that the electric motor is operated with pulsed voltage, whereby the pulsed voltage has a pulse-pause ratio whose pause is such that the DC-to-DC converter will even power the control circuit if it only operates during the pauses.