| 摘要 |
PURPOSE:To make it not always necessary to stabilize drive power source and simplify the structure by converting voltage change of drive power source into pulse width of drive pulse through analog-digital conversion and by controlling thereby a drive current of solenoid. CONSTITUTION:When a drive pulse which is a latch signal outputted from flip- flop circuit 8 is given to a switch 9, a drive power source voltage 2 drops due to a load. The pulse width of drive pulse 1 is changed in accordance with dropping condition. Namely, a constant energy is always supplied to a solenoid. The flip-flop circuit 8 is set by the excitation start signal 7 and thereby the solenoid 10 is excited. A counter 5 counts up and thereby the reset signal is input to the flip-flop circuit 8. Accordingly, an excitation current of solenoid is cut off. Responding to the excitation start signal 7, the analog-digital converter 3 converts a voltage of drive power source 11 into a digital signal at the adequate timing and then inputs it to an adder 4. |
