Motor drive circuit

A motor system comprising:

• a motor;
• a power source for driving said motor;
• a PWM wave generation circuit that generates a PWM wave having a high frequency and a pulse width modulated in accordance with a rotational frequency control signal, the PWM wave being sent to said motor;
• a semiconductor switching element that performs switching operation upon input receipt of the PWM wave output from said PWM wave generation circuit;
• and
• a current resonance circuit that induces current resonance in response to source power imparted by switching operation of said semiconductor switching element.

A motor drive circuit comprising:

• a power source for driving a motor;
• a PWM wave generation circuit that generates a PWM wave having a high frequency and a pulse width modulated in accordance with a rotational frequency control signal;
• a semiconductor switching element that performs switching operation upon input receipt of the PWM wave output from said PWM wave generation circuit;
• and
• a current resonance circuit that induces current resonance in response to source power imparted by switching operation of said semiconductor switching element,
• wherein one terminal of said semiconductor switching element is connected to the motor and to an element of said current resonance circuit.