Patent Number: 7,714,528

Title: Fan driving circuit

Abstract: A fan driving circuit includes a digital-analog converting circuit (10), an amplifier circuit (40), and a controlling circuit (50). The digital-analog converting circuit receives a digital signal from a controlling integrated circuit (IC), and outputs an analog signal. The amplifier circuit receives the analog signal from the digital-analog converting circuit, and outputs an amplified analog signal at an output terminal. The controlling circuit includes an isolation diode (D1), a transistor (Q1), and a resistor (R4), an anode of the isolation diode is coupled to an output terminal of the amplifier circuit, a cathode of the isolation diode is coupled to a base of the transistor, the base of the transistor is coupled to a power supply (Vcc1) via the resistor, a collector of the transistor is coupled to the power supply, an emitter of the transistor is coupled to a fan (60).

Inventors: Chen; Ying (Shenzhen, CN), Xiong; Jin-Liang (Shenzhen, CN)

Assignee: Hong Fu Jin Precision Industry (ShenZhen) Co., Ltd.

International Classification: G05B 11/28 (20060101)

Expiration Date: 5/11/12018