| 摘要 |
PROBLEM TO BE SOLVED: To provide a current control device which raises the heater temperature to an appropriate temperature within a short time when using a PTC heater, without contracting a large power supply. SOLUTION: For the current control method, the current flowing at heater is controlled by using a thyristor and a current detecting means, and by adjusting the pulse width of a gate signal inputted to the thyristor corresponding with the detected current. An allowable range of the current to be supplied to the heater is set in advance, and the detection of the value of the current flowing at the heater is started by switching on and inputting the gate signal with an optional pulse width, and optional values are repeatedly added to the pulse width until the detected current value gets into the allowable range. After the detected current value gets into the allowable range, the pulse width is maintained by stopping the addition of the pulse width. When the detected current value falls below the allowable range, the addition of the pulse width is re-started until the detected current value gets into the allowable range, and when the detected current value exceeds the allowable range, optional values are repeatedly subtracted from the pulse width, until the detected current value gets back to the allowable range.
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