Semiconductor device

• US 8,328,105 B2
• Filed: 03/26/2010
• Issued: 12/11/2012
• Est. Priority Date: 03/31/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Fujita, Masashi
• Primary Examiner(s): Le, Thien M
• Application Number:
  US12/732,863
• Publication Number:
  US 20100243744A1
• Time in Patent Office: 991 Days
• Field of Search: 235/492, 235/493, 235/491, 235/486, 235/487, 235/383, 235/380, 235/382, 235/375
• US Class Current: 235/492
• CPC Class Codes: G06K 19/0701 at least one of the integrated circuit chips comprising an arrangement for power management
• CPC Class Codes: G06K 19/0715 the arrangement including means to regulate power transfer to the integrated circuit
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs

Abstract

An object is to provide a semiconductor device which operates stably even when the communication distance between a reader/writer and a non-contact data carrier is largely changed. A protection circuit is provided in the non-contact data carrier, and an operating state and a non-operating state of the protection circuit are switched depending on the communication distance between the reader/writer and the non-contact data carrier. The operating point at which the operating state and the non-operating state of the protection circuit are switched is different between the case where input voltage of the protection circuit is low in an initial state and then gradually raised and the case where input voltage of the protection circuit is high in an initial state and then gradually lowered.

Claims

1. A semiconductor device comprising:

an antenna;

a first transistor, wherein a drain and a gate of the first transistor is electrically connected to one end of the antenna;

a first resistor, wherein one end of the first resistor is electrically connected to a source of the first transistor;

a second transistor, wherein one of a source and a drain of the second transistor is electrically connected to the one end of the first resistor, and a gate of the second transistor is electrically connected the other end of the first resistor;

a second resistor, wherein one end of the second resistor is electrically connected to the other of the source and the drain of the second transistor;

one or a plurality of third transistors, wherein a drain and a gate of any one of the one or the plurality of third transistors is electrically connected to the other end of the first resistor;

a fourth transistor, wherein a gate of the fourth transistor is electrically connected to the one end of the second resistor and the other of the source and the drain of the second transistor; and

a fifth transistor, wherein a gate of the fifth transistor is electrically connected to the gate of the fourth transistor, and one of a source and a drain of the fifth transistor is electrically connected to the drain and the gate of the first transistor,

wherein the other end of the antenna, a source of the one or the plurality of third transistors, the other end of the second resistor, the other of the source and the drain of the fourth transistor, and the other of the source and the drain of the fifth transistor are grounded.

2. The semiconductor device according to claim 1, wherein the plurality of third transistors are connected in series.

3. The semiconductor device according to claim 2, wherein the drain and the gate of any one of the plurality of third transistors are electrically connected to one of the source and the drain of the fourth transistor.

4. The semiconductor device according to claim 1, further comprising a third resistor, wherein one end of the third resistor is electrically connected to the source of the first transistor, and the other end of the third resistor is grounded.

5. A non-contact data carrier comprising the semiconductor device according to claim 1.

6. A non-contact data carrier the semiconductor device according to claim 1, wherein the first resistor, the second transistor, the one or the plurality of third transistors, and the fourth transistor are included in a protection circuit.

7. A non-contact data carrier comprising:

an antenna circuit comprising an antenna;

a logic circuit;

a demodulation circuit;

a modulation circuit;

a protection circuit; and

a rectifier circuit,

wherein a first operating point at which an operating state and a non-operating state of the protection circuit are switched in the case where the level of input voltage of the protection circuit is low in an initial state and then gradually raised is different from a second operating point at which an operating state and a non-operating state of the protection circuit in the case where the level of input voltage of the protection circuit is high in an initial state and then gradually lowered, and

wherein the protection circuit comprises;

a first resistor, wherein one end of the first resistor is electrically connected to the rectifier circuit;

a first transistor, wherein one of a source and a drain of the first transistor is electrically connected to the one end of the first resistor, and a gate of the first transistor is electrically connected the other end of the first resistor;

a second resistor, wherein one end of the second resistor is electrically connected to the other of the source and the drain of the first transistor;

one or a plurality of second transistors, wherein a drain and a gate of any one of the one or the plurality of second transistors is electrically connected to the other end of the first resistor; and

a third transistor, wherein a gate of the third transistor is electrically connected to the one end of the second resistor and the other of the source and the drain of the first transistor.

8. The non-contact data carrier according to claim 7,

wherein the rectifier circuit comprises a fourth transistor, wherein a drain and a gate of the fourth transistor is electrically connected to one end of the antenna.