Patent ID: 7598690
Filing Date: 2009-10-06
Classification: H02P

Abstract:
1. A start-up circuit for a DC (direct current) fan, comprising: a digital-analog converter for converting a digital control signal to an analog control signal, the digital-analog converter comprising an output terminal; a voltage sampling device connected to the output terminal of the digital-analog converter, the voltage sampling device comprising an output terminal; a comparator comprising two input terminals and an output terminal, one of the input terminals being connected to the output terminal of the voltage sampling device; a switching device for controlling start-up of the DC fan, the switching device being connected to the output terminal of the comparator; and a feedback device connected between an output terminal of the switching device and the other one of the input terminals of the comparator for adjusting a current passing through the switching device for the DC fan, an output signal of the switching device being inputted to the other one of the input terminals of the comparator via the feedback device.