| 摘要 |
PURPOSE:To obtain a control circuit, in which current abnormality can be promptly detected even for a motor of large DC component, by adding the DC component, extracted from a current detection circuit, to an output of a current reference generation circuit that serves as the abnormal current detection reference which is compared with an output current of the above-mentioned current detection circuit. CONSTITUTION:A DC component, which is obtained with a current feedback signal from a current detection circuit 7 through a DC component extraction circuit 10 constituted of a low pass filter or the like, is added by an adder 11 to be output of a reference value generation circuit 8 with the abnormal current detection reference obtained. For performing abnormal current detection by comparing this abnormal current detection reference with the current feedback signal from the above-mentioned current detection circuit 7 by the use of a comparator 9b, an alarm zone vertically symmetrical for the DC component of a motor can be formed. Accordingly, generation of an abnormal current can be promptly found with minimized damage. |
