Drive of an electromagnetic valve with a coil by supplying high voltage from a discharging capacitor to the coil

摘要

An electromagnetic valve driving apparatus is provided for reducing emission noise generated when a discharge switching element is turned off. In the apparatus, a discharging capacitor stores electrical energy for performing discharge to a coil in an electromagnetic valve and charging means generates voltage from a power source voltage, which voltage is higher than that of the power source voltage. A discharge switching element is provided in series in a current path extending from the discharging capacitor to an up-stream side terminal of the coil. Controlling means turns on/off the discharge switching element. Circulating means is provided in the current path for circulation of current to the coil. Sub-discharging means is provided in the current path, for starting discharge to the coil when the discharge switching element is turned off, and for circulating current to the coil through the circulating means when the discharge to the coil is completed.