Title: Pen control circuit
Application Number: 86102282 Application Date: 1986.04.02
Publication Number: 1003630 Publication Date: 1986.10.01
Approval Pub. Date: 1993.05.12 Granted Pub. Date: 1993.05.12
International Classifi-cation: B43L13/00;G05D3/00;G05D13/00;G05D15/00
Applicant(s) Name: Iwatsu Electric Co., Ltd. Address:
Inventor(s) Name: Shinji Hayashi
Attorney & Agent: DENG MING
Abstract:
    A pen control circuit includes a current control circuit for controlling the magnitude of a driving force of a drive coil, a feedback circuit for supplying a feedback signal to the current control ciruit, a clipper for extracting the pen position detection signal only when the level of the pen is higher than a predetermined level with respect to a recording surface, and a selector for selecting first, an output from the clipper as a drive current setting value of the current control circuit during an initial pen-down period and second, the pen pressure setting signal as the drive current setting value after the output from the clipper is disabled. The pen control circuit also includes a current setting circuit for supplying a predetermined drive current setting value to the current control circuit in a pen-up mode and a limiter for limiting a current supplied to the drive coil in accordance with a pen position detection signal when the pen is moved upward to a predetermined position.
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