To provide an electronic pen that can charge an electric double-layer capacitor in a short time and with high efficiency in a range not exceeding above an electric current maximum value of a charging electric power.
An electronic pen having position display means for position information according to the present invention is configured to comprise: capacitor voltage monitor means that detects voltages of a step-up or step-down converter supplying power to the position display means, the electric double-layer capacitor accumulating supply power for the position display means and the electric double-layer capacitor; a step-down type chopper circuit that controls a charging electric current of the electric double-layer capacitor; and switch control means that controls an ON/OFF duty of the step-down type chopper circuit on the basis of voltage information detected by the capacitor voltage monitor means. The switch control means controls such that the ON duty of the step-down type chopper circuit gets greater as the voltage information detected by the capacitor voltage monitor means gets greater.
HIRATA KOJI
ISHIKAWA TATSUYA
FUJIKURA TSUNEO
IKEDA MIYUKI
KANBARA TAKASHI
KIMOTO TOSHIYUKI
| JP2010086542A | 2010-04-15 | |||
| JP2011188640A | 2011-09-22 |
Yuji Toda
Shigemi Iwasaki