| 摘要 |
<p>PURPOSE: To switch the rotating direction of a motor by a simple control signal and, further, improve the reliability without adding a circuit detecting the abnormality, a circuit detecting an excessive current, etc., and reduce the cost. CONSTITUTION: When the level of a rotation signal (a) is turned to low from high, the level of the output of a Schmidt trigger inverter 8 immediately decreased and the level of the output of a Schmidt trigger inverter 7 increases with a certain delay time. Then, if the level of the rotation signal (a) increases from low in order to switch the rotating direction of a motor 1, the level of the output of the Schmidt trigger inverter 7 immediately decreases and the level of the output of the Schmidt trigger inverter 8 increases with a certain delay time. When the rotating direction of the motor 1 is switched; therefore, a period during which all the switching devices 2-5 are turned off is forcibly inserted and the short circuit of the switching device caused by the abnormality can be avoided, so that the reliability can be improved without any additional circuits and the cost can be reduced.</p> |
