| 摘要 |
PROBLEM TO BE SOLVED: To provide a driver circuit capable of properly driving a plurality of kinds of solenoids. SOLUTION: In the solenoid driver circuit 12, the magnitudes of voltage corresponding to a signal Sduty from a micro computer 10 and a triangular wave from a triangular-wave generating circuit 32 are compared by a comparator 34, and a duty driving signal is transmitted to a gate for an FET 22 for conducting electricity through a solenoid from the comparator 34. Constant voltage Vts is input to the comparator 34 in the case of a high test signal Stest from the micro computer 10, and a driving signal in constant frequency at a constant duty ratio is transmitted to the FET 22. Whether or not the solenoid 1 is either of two kinds is discriminated according to whether or not an average current flowing through the solenoid L to be driven reaches a fixed value or more in this case, and the result of the discrimination is stored in a flip-flop 56 in the case of the fall of the test signal Stest. Thus, the output frequency of the triangular-wave generating circuit 32 in a normal case and an overcurrent decision level in an overcurrent detector 36 are set in response to the stored result.
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