The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 30, 2007
Filed:
Apr. 26, 2002
Kazuki Watanabe, Kokubunji, JP;
Hisataka Tsunoda, Oomama, JP;
Norihisa Yamamoto, Kodaira, JP;
Kazuhiro Matsushita, Kodaira, JP;
Kazuki Watanabe, Kokubunji, JP;
Hisataka Tsunoda, Oomama, JP;
Norihisa Yamamoto, Kodaira, JP;
Kazuhiro Matsushita, Kodaira, JP;
Renesas Technology Corp., Tokyo, JP;
Hitachi ULSI Systems Co., Ltd., Tokyo, JP;
Abstract
In an IC card in which an internal circuit is operated by an internal power supply formed from alternate current from outside received by an antenna, the voltage of the internal power supply sometimes changes due to the operation of the internal circuit. Therefore, the voltage controlling circuit of the present invention includes a voltage controlling current source, and when the internal circuit is not operated and the current higher than a predetermined current is detected in the voltage controlling current source, an operating current detector circuit outputs an enable signal. When the internal circuit is operated in response to the enable signal, the current consumed in the internal circuit is subtracted from the current passing through the voltage controlling current source. Consequently, the current change in the entire internal power supply can be prevented, and the output voltage of the internal power supply can be kept constant.