发明申请
- 专利标题： CONSTANT VOLTAGE CIRCUIT AND ELECTRONIC DEVICE INCLUDING SAME
- 专利标题（中）： 恒定电压电路和包括其的电子器件
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申请号： US13719454申请日： 2012-12-19
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公开(公告)号： US20130154605A1公开(公告)日： 2013-06-20
- 发明人: Toshihisa Nagata , Takahiro Hino , Akihito Nagahama
- 申请人： Toshihisa Nagata , Takahiro Hino , Akihito Nagahama
- 申请人地址： JP Tokyo
- 专利权人： RICOH COMPANY, LTD.
- 当前专利权人： RICOH COMPANY, LTD.
- 当前专利权人地址： JP Tokyo
- 优先权： JP2011-278561 20111220
- 主分类号： G05F3/02
- IPC分类号： G05F3/02
摘要：
A constant voltage circuit includes an output control transistor to control an output current from an output terminal to keep an output voltage constant at a set voltage; and an excess-current protection circuit to control the output control transistor. The excess-current protection circuit includes a current increase restriction element to restrict increase in the output current to decrease the output voltage; a first current limitation circuit to limit a gate voltage of the output control transistor to decrease the output current, when the output voltage is decreased to a first limited voltage; a second current limitation circuit to limit a gate voltage of the output control transistor to decrease the output current, when the output voltage is decreased to a second limited voltage smaller than the first limited voltage; and a selector to select whether the first current limitation circuit is operated or stopped.