| 摘要 |
PURPOSE:To make a maximum current variation to a variation in supply voltage approachable to an ideal demand value, by turning on a second switching device connected to a current limiting resistor in parallel in the input initial stage of an injection pulse signal. CONSTITUTION:When an injection pulse signal is inputted into a motion starting transistor 15 is turned on, whereby a condenser 11 being charged to an almost fixed value by constant voltage discharges via a discharging variable resistance 14. Therefore, a falling curve of charging voltage of the condenser 11 due to the discharge is almost constant and varies logarithmically and functionally. Accordingly, short time of a current limiting resistor 2 made by a short- circuiting transistor 5 is short and less variation when it varies at a range where battery supply UB voltage is high, but it is long and its variation grows larger when it varies at a low range. With this, a maximum value of a driving current flowing into a solenoid 1 is also varied, thus approaching to the demand value.
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