Importance

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Abstract

The present invention provides a current control apparatus for a DC motor system having a motor field coil and a motor armature and driven by the power of a battery, and a chopper transistor for controlling the amount of the current supplied to the DC motor from the battery, which current control apparatus has current amplifying means for detecting the current amount at the rear end of the motor and amplifying the current value; on-off control means for comparing the input current with the current supplied from the current amplifying means and outputting an on-off control signal according to the current amount; and a microcomputer for controlling the duty value of the pulse wave of a predetermined frequency occurring in accordance with the on-off control signal from the on-off control means and controlling the on-off time of the chopper transistor. The microcomputer performs the following steps: a step for determining whether or not an interrupt counter is an initial state, setting an initial state if yes and setting the outputting pulse limiting value of the microcomputer; a step for determining whether or not the duty value of the microcomputer output pulse is 0 in case of non-initial state of the interrupt counter; and a step for comparing the interrupt counter is not in the initial state, whether the predetermined current limit value is 0; comparing, if the predetermined current limit value is not 0, the state of said interrupt counter with said predetermined current limit value and thereby controlling an on-off state of said chopper transistor; and turning off said chopper transistor if the predetermined current limit value is 0.

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First Claim