Patent ID: 8662471

Claim:
A solenoid valve comprising: a valve body including a flow passage, a valve member that opens and closes the flow passage, a valve seat on or from which the valve member can be seated or unseated, a stem that operates opening/closing of the valve member, and a spring that biases the stem; a solenoid that is connected with the valve body and that actuates the stem; a motive power supply that is a unit comprising a charging power supply for supplying a driving electric power to the solenoid with an electric double layer capacitor, and a control circuit, including a step-down converter, that controls the driving electric power supplied from the charging power supply to the solenoid in accordance with a command; and a casing that is attached integrally to the valve body and that houses the motive power supply; wherein the control circuit includes a first discharge line that is connected to the charging power supply to supply a starting current to the solenoid, a second discharge line that has the step down converter disposed therein and that is connected to the charging power supply to supply, to a solenoid coil, a holding current for holding a state in which a movable iron core is attracted, a switching circuit that switches between the first discharge line and the second discharge line to supply power to the solenoid, and a timing circuit that controls the timing of a switching operation of the switching circuit.