Patent ID: 7714528
Filing Date: 2010-05-11
Classification: H02P

Abstract:
1. A fan driving circuit, comprising: a digital-analog converting circuit configured for receiving a digital signal from a controlling integrated circuit (IC), and outputting an analog signal; an amplifier circuit configured for receiving the analog signal from the digital-analog converting circuit, and outputting an amplified analog signal at an output terminal thereof and a controlling circuit comprising an isolation diode, a transistor, and a first resistor, an anode of the isolation diode coupled to the output terminal of the amplifier circuit to receive the amplified analog signal from the amplifier circuit, a cathode of the isolation diode coupled to a base of the transistor via a current limiting resistor, the base of the transistor coupled to a power supply via the first resistor, a collector of the transistor coupled to the power supply, an emitter of the transistor coupled to a fan.