| 摘要 |
PURPOSE:To make the capacity of a transformer for a proportional valve circuit small by applying individual power supplied to the proportional valve control circuit and a valve driving circuit through a process of transmitting signals of a proportional valve control circuit and the proportional valve driving circuit with a photocoupler or the like. CONSTITUTION:Together with providing a proportional valve driving circuit 2 having an electric current control circuit 7 connected to a proportional valve 6 for deciding a driving current according to an input signal V1 and an input signal forming circuit 8 for forming input signal V1 and a proportional valve control circuit 4 having a pulse signal generating circuit 16 having the pulse width according to opening/closing quantity of the proportional valve an electrically insulated signal transmitting means 20 like a photocoupler 20 is interposed between the proportional valve driving circuit 2 and the proportional valve control circuit 4. Thereby, it can be achieved to apply individual power supplies to the proportional valve driving circuit 2 and the proportional valve control circuit 4 for making capacity of a transformer 3 small through feeding only electric power to the control circuit 4 from the transformer 3.
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