Power supply circuit in IC chip for non-contact IC card

• US 20060255159A1
• Filed: 05/11/2005
• Published: 11/16/2006
• Est. Priority Date: 05/11/2005
• Status: Abandoned Application

• Current Assignee: Fec Co., Ltd., Government of Malaysia
• Original Assignee: FEC Company Limited and The Government of Malaysia
• Inventors: Taniguchi, Shuhei, Kobayashi, Hideki, Sugimura, Shiro
• Application Number:
  US11/126,619
• Publication Number:
  US 20060255159A1
• Time in Patent Office: Days
• 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 19/0723 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

The capacitance of a smoothing capacitor is reduced, and the size of an IC chip is minimized. A series transistor is provided on the output side of a diode which rectifies the output voltage of an antenna, and the smoothing capacitor is connected to the base of the series transistor. If the current gain of the series transistor T is β, then the apparent capacitance of the smoothing capacitor C2 is multiplied by β.

Claims

1. A power supply circuit in an IC chip for a non-contact IC card, comprising:

an antenna;

a diode, which rectifies the output voltage of said antenna;

a series transistor, inserted at the output side of said diode; and

,

a smoothing capacitor, connected to the base of said series transistor; and

wherein

said smoothing capacitor is formed integrally on the IC chip, together with a main portion having memory functions and communication functions.

2. The power supply circuit in an IC chip for a non-contact IC card according to claim 1, wherein said smoothing capacitance has a capacitance on the order of several picofarads.

3. The power supply circuit in an IC chip for a non-contact IC card according to claim 1 or claim 2, wherein said smoothing capacitor is realized through stray capacitance of circuitry.

4. The power supply circuit in an IC chip for a non-contact IC card according to claim 1, wherein a supplementary transistor supplying a base current is provided as an adjunct to said series transistor.

5. The power supply circuit in an IC chip for a non-contact IC card according to claim 4, wherein said supplementary transistor has a voltage-limiter function.

6. The power supply circuit in an IC chip for a non-contact IC card according to claim 1, wherein the output side of said diode is connected to the output side of another diode which rectifies the output voltage of an external antenna.