| 摘要 |
PURPOSE:To reduce noise by converting sinusoidal wave detection signal corresponding to the rotating position of a rotor into trapezoidal waves and by performing with it the operation control of a drive circuit, CONSTITUTION:A drive circuit of a two-phase one-way brushless motor is equipped with a position detection circuit 1, a trapezoidal wave formation circuit 2 and a drive circuit 3 and is integrally formed into an integrated circuit 4. This position detection circuit 1 is equipped with a Hall element 5 installed onto a stator core of the motor and a magnet for position detection. The bias current of the Hall element 5 is given from a terminal 4a of the integrated circuit 4. The trapezoidal wave formation circuit 2 is composed of the 1st and 2nd differential amplifiers 7 and 8 and a bias circuit 9 is provided for supplying constant bias current. Further, the operation control of the drive circuit 3 is performed with trapezoidal wave signals A3 and B3. The waveform of driving current to drive a plurality of motor coils La and Lb is made trapezoidal. |
