| 摘要 |
PURPOSE:To enable a small-capacity switching element to be used by increasing a current flowing through the coil of a solenoid valve by decreasing the resistance value of a resistor for current detection. CONSTITUTION:A comparator 12 compares the output (b) of an integrator 25 with the output (c) of an oscillator 20 and, when the output of the integrator is greater, outputs a high-level signal. Therefore, when an amplifier output voltage (f) corresponding to a current flowing through a coil 14 is lower than, for example, a control input voltage (a), the integral output (b) of the integrator 25 rises on the average and the conduction time of a transistor 17, therefore, increases, increasing the current flowing through the coil 14. Thus, the current is supplied to the coil 14 in proportion to the control input voltage (a). |
