| 摘要 |
PURPOSE: To reduce the size and cost of a speed controller for motors, by configuring its speed switching circuit out of one two-input logical circuit and a switching circuit, and by simplifying the circuit configuration of the speed switching circuit. CONSTITUTION: To a two-input logical circuit 5A, a speed sensing signal Va and its divided-frequency signal Vb are inputted, and the potential of the input terminal whereto the signal Vb is inputted is maintained at a high or low level regardless of the state of the signal Vb. Thereby, a first signal whose frequency is equal to the speed sensing signal Va can be outputted from the logical circuit 5A. Also, the foregoing maintenance of the potential of the input terminal whereto the signal Vb is inputted is released, and the potential of this input terminal is forced to change according to the level change of the signal Vb. Thereby, a second signal whose frequency is equal to the signal Vb can be outputted from the logical circuit 5A. In this manner, since a speed switching circuit 5 can be configured by the one two-input logical circuit 5A, the circuit configuration of the speed switching circuit 5 can be simplified, and the size and cost of a speed controller for motors can be reduced easily. |
