| 摘要 |
PURPOSE:To enable to obtain an ultrafine counterelectromotive force without voltage loss nor voltage loss at the smoothing time by obtaining the counterelectromotive force generated from a stator coil of a brushless motor by a level shifter and a peak detector. CONSTITUTION:A level shifter 4 inputs counterelectromotive forces generated at stator coils L1, L2 through resistaors R1, R2, and outputs a voltage signal which is shifted at level to P3 point. A peak detector 5 holds the peak value of the output voltage of the P3 point of the shiter 4 in a capacitor C, and outputs to a P4 point. An error amplifier 7 controls the output current I0 of a transistor 8 in response to the error between the voltage at the P4 point and the voltage of a reference voltage source 7. Transistors Q9, Q10 supply a current in response to the current I0 by the output of a position detector 3 to the stator coils L1, L2. |
