| 摘要 |
PURPOSE:To keep the magnetomotive force of a motor coil constant, and to reduce the adverse effect of back electromotive force by changing the level of output voltage from a low-output impedance drive circuit for driving inductance load by stages. CONSTITUTION:Outputs from revolution-position detecting elements H1-H3 detecting the position of revolution of a stator are transmitted over matrix circuits 21-23 through Hall amplifiers 11-13, waveform shaping circuits 14-16 and transistors Q21-Q23 constituting P-N-P current mirror circuits. The matrix circuits 21-23 have the same constitution, the matrix circuit 21 is composed of a sign reversing circuit 211, a current synthetic circuit 212 and a current voltage conversion circuit 213, output currents from the current synthetic circuit 212 are changed by stages,and the output currents are inputted to the voltage conversion circuit 213 and converted into output voltage, and fed to motor coils L1 through an output circuit 24. |
