Fan brake circuit

A fan brake circuit comprising:

• a semiconductor switch unit having a first end and a second end, the first end serving to receive an input power;
• a motor electrically connected with the input power and the first end;
• a motor drive circuit electrically connected with the motor for outputting a drive signal to the motor;
• an isolation unit electrically connected between the semiconductor switch unit and the motor drive circuit, the isolation unit having multiple resistors respectively electrically connected with the motor drive circuit and the second;
• a charging/discharging unit electrically connected with the multiple resistors for receiving and storing an operation voltage;
• and
• a control unit electrically connected with the input power and the motor drive circuit and the motor for outputting multiple control signals to respectively control the motor drive circuit and the motor, whereby when the fan is powered off, the semiconductor switch unit disconnects the first end from the motor and the motor drive circuit receives the operation voltage provided by the charging/discharging unit to transmit the drive signal to the motor so that the motor forms a short-circuit and brakes.