Patent ID: 6946809

Claim:
A motor driving system comprising a power supply unit, a voltage-stabilizing unit, and a driving element; said power supply unit providing an input supply voltage to said voltage-stabilizing unit and said driving element; said voltage-stabilizing unit including a voltage-stabilizing element and producing a constant voltage which is provided to said driving element; and said driving element including a signal-generating unit, a comparing unit, and a control unit; said signal-generating unit being adapted to generate an input signal, which varies with high and low levels of the input supply voltage from said power supply unit; said comparing unit being adapted to compare the constant voltage produced by said voltage-stabilizing unit with the input signal generated by said signal-generating unit, and to generate a comparison signal; and said control unit being adapted to control a motor's rotating speed according to the comparison signal generated by said comparing unit; whereby when the input supply voltage supplied from said power supply unit is low and the input signal generated by said signal-generating unit changes, said comparing unit compares the constant voltage provided by said voltage-stabilizing unit and the changed input signal to generate said comparison signal, according to which a lowest motor speed is set for said control unit to control the rotating of the motor.