Fan system and power reverse protection apparatus thereof

A power reverse protection apparatus, electrically connected to a fan and a power source, wherein the power source is electrically connected to a voltage regulator, the voltage regulator is electrically connected to a driver, the driver is electrically connected to the fan, and an input signal generated by the power source is converted to a driving signal by the voltage regulator and the driver, the power reverse protection apparatus comprising:

• a voltage regulator switch receiving the input signal from the power source and outputting a first output signal according to the input signal;
• and
• an activating device electrically connected to the voltage regulator switch, receiving the input signal and the first output signal respectively, and outputting a second output signal to the fan according to the first output signal;
• wherein the fan operates or stops according to the driving signal and the second output signal,
• wherein the activating device comprises:
• a P-type power element has a first terminal, a second terminal, a third terminal, and a fourth terminal, wherein the first terminal is electrically connected to the power source for receiving the input signal, the second terminal is electrically connected to the fan, the third terminal is electrically connected to the voltage regulator switch for receiving the first output signal, the P-type power element is turned on or turned off according to the first output signal, and the second terminal is electrically connected to the fourth terminal for forming a body diode between the first terminal and the second terminal;
• and
• a first zener diode has two ends electrically connected to the second terminal and the third terminal of the P-type power element respectively,
• wherein the voltage regulator switch comprises:
• a transistor having a first terminal, a second terminal, and a third terminal, wherein the second terminal of the transistor is grounded;
• a second resistor having a first terminal electrically connected to the third terminal of the transistor and a second terminal electrically connected to the power source;
• and
• a third resistor having a first terminal electrically connected to the first terminal of the transistor and a second terminal electrically connected to the third terminal of the P-type power element,
• wherein the third terminal of the transistor receives the input signal and outputs the first output signal to the first terminal of the transistor in accordance with the input signal so as to turn on or turn off the P-type power element.