Patent ID: 9488183
Filing Date: 2016-11-08
CPC Classification: F04D,G06F,H02P

Claim Text:
1. A fan rotation speed controlling device, comprising: a first transistor for receiving a pulse-width modulation (PWM) signal, the first transistor having a first end, a second end, and a third end, wherein the first end of the first transistor receives the PWM signal, and the third end of the first transistor is grounded; a second transistor and a third transistor for amplifying the PWM signal, the second transistor having a first end, a second end, and a third end, wherein the first end of the second transistor is directly electrically connected to the second end of the first transistor, and the second end of the second transistor is directly electrically connected to a power source, the third transistor having a first end, a second end, and a third end, wherein the first end of the third transistor is directly electrically connected to the second end of the first transistor, the second end of the third transistor is grounded, and the third end of the third transistor is directly electrically connected to the third end of the second transistor; a fourth transistor for receiving the amplified PWM signal such that a working state of the fourth transistor is changed according to the amplified PWM signal to thereby control a magnitude of an output voltage, the fourth transistor having a first end, a second end, and a third end, wherein the first end of the fourth transistor receives the amplified PWM signal, and the third end of the fourth transistor is directly electrically connected to the power source; a first resistor, a second resistor, and a first diode, wherein the first resistor has a first end directly electrically connected to the first end of the first transistor and a second end directly electrically connected to a cathode of the first diode, the second resistor has an end directly electrically connected to the first end of the first resistor and has an opposite end grounded, and the first diode has an anode for receiving the PWM signal; and at least one heat dissipation fan connected to the second end of the fourth transistor such that a rotation speed of the heat dissipation fan is changed according to variation of the output voltage.