| 摘要 |
PURPOSE:To shut OFF a driving circuit at the time of restriction and to prevent heat generation, electric energy loss of the circuit at the time of restriction by detecting a motor pulse at a polarity switching point and turning ON, OFF a motor at the generating interval of the pulse. CONSTITUTION:A motor pulse P is present at a motor terminal T1 at the time of switching a polarity. The pulse P is output from a connecting point 2 of the terminal T1 and an inductor L, and applied to a pulse detector 3. If the generating interval of the pulses P is increased, a driving control voltage S4 exceeds a threshold value to attain a high level. Since the output SD of a NAND circuit 10 is converted to a low level, a driving transistor Q1 is turned OFF to stop energizing a DC motor M. Accordingly, when the motor M is restricted, it can effectively prevent a restriction current from flowing. Even if the performance of a power source is lowered, this shut-off is effectively performed to reduce heat generation of the circuit, electric energy loss. |
