Semiconductor device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorTaichi Kato
Life of this patent
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Abstract
It is an object of the present invention to provide a semiconductor device which can be surely supplied electric power by electromagnetic waves in different frequency bands without preventing reduction in size and weight of a semiconductor device. A semiconductor device capable of wireless communication is provided with a frequency determining circuit which detects the frequency of the electromagnetic waves received by the antenna and a circuit which automatically adjusts impedance in accordance with information from the frequency determining circuit, and the semiconductor device communicates and obtains electric power by one antenna. For adjustment of impedance, a circuit which can change the inductance or the capacitance, or an antenna which can change the length is used.
Claims10
A semiconductor device comprising:
- an antenna;
- and
- a frequency determining circuit,
- wherein the antenna includes a first portion and a second portion,
- wherein a first switch is provided between the first portion and the second portion,
- wherein the first portion and the second portion are electrically connected to the first switch,
- wherein a first terminal of the frequency determining circuit is electrically connected to a second terminal of the antenna, and
- wherein the frequency determining circuit is configured to control the first switch in accordance with a frequency of electromagnetic waves received by the antenna.
A semiconductor device comprising:
- an antenna;
- a frequency determining circuit;
- and
- a demodulation circuit,
- wherein the antenna includes a first portion and a second portion,
- wherein a first switch is provided between the first portion and the second portion,
- wherein the first portion and the second portion are electrically connected to the first switch,
- wherein a first terminal of the frequency determining circuit is electrically connected to a second terminal of the demodulation circuit,
- wherein a third terminal of the demodulation circuit is electrically connected to a fourth terminal of the antenna, and
- wherein the frequency determining circuit is configured to control the first switch in accordance with a frequency of electromagnetic waves received by the antenna.
A semiconductor device comprising:
- an antenna;
- a frequency determining circuit;
- and
- a rectifier circuit,
- wherein the antenna includes a first portion and a second portion,
- wherein a first switch is provided between the first portion and the second portion,
- wherein the first portion and the second portion are electrically connected to the first switch,
- wherein a first terminal of the frequency determining circuit is electrically connected to a second terminal of the rectifier circuit,
- wherein a third terminal of the rectifier circuit is electrically connected to a fourth terminal of the antenna, and
- wherein the frequency determining circuit is configured to control the first switch in accordance with a frequency of electromagnetic waves received by the antenna.
Dependencies are inferred from the claim text.