| 摘要 |
PURPOSE:To obtain a correct position detection signal following to variation in a load by providing a positive feedback circuit at a comparator of a comparing circuit, and varying a feedback amount by a load detector for sending a PWM signal corresponding to the magnitude of a load of a brushless motor. CONSTITUTION:A load detector 17 outputs a DC voltage responsive to a distortion in the output waveform from an average value detected from the output waveform of an integrator and a peak value to a distortion detector 18 connected to the output terminal of an integrator 11. A pulse width modulation signal corresponding to the magnitude of a load is output by level comparing the output with the output of a triangular wave generator 22, sent to the switching element of a feedback circuit 16 to control ON, OFF the element, thereby controlling the positive feedback amount. The phase of a position detection signal is continuously delayed in response to the magnitude of the load of a brushless motor to be corrected. The detector 17 for detecting the magnitude of the load from a load current detector continuously delays the phase of the detection signal to be corrected. |
