| 摘要 |
PURPOSE:To reduce the number of elements and to improve the reliability and the flexibility by constituting a solenoid valve driving device with a target current output command means, a monitor means, a comparing means, an on/off switching means, a pulse generating means, a counter means, and a duty designating means. CONSTITUTION:A command means 2 obtains a voltage corresponding to a target average current of a solenoid valve coil 1 and outputs it to a comparator 4. The current of a monitor means 3, namely, the current of the coil 1 is inputted to the comparator 4 and is compared with the average current. A counter 7 measures the period from the time, when a transistor TR 5 is changed from the turn-off state to the turn-on state to start to increase the current of the coil 1, to the time when the current of the coil 1 and the target average current coincide with each other in the comparator 4. A duty command means 8 receives the measured result of the counter 7 and multiplies it by a coefficient corresponding to the target average current to operate the turn-on time of the TR 5, namely, the duty. Thus, the duty of the output pulse train of a pulse generating means 6 is determined to make the average current flowed to the coil 1 coincident with the target average current. |
