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Smartcard performance enhancement circuits and systems

  • US 8,451,122 B2
  • Filed: 03/01/2011
  • Issued: 05/28/2013
  • Est. Priority Date: 08/08/2008
  • Status: Active Grant
First Claim
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1. An apparatus comprising:

  • an integrated circuit having a contactless interface that includes two pads intended for connection to a coil, wherein the integrated circuit includes load modulation circuitry coupled to one of the two pads for half duplex communication when the coil is inductively coupled to a coil of a separate device;

    a coil;

    an amplifier coupled to receive a signal from the coil when the coil is inductively coupled, and to drive one of the two pads, the amplifier providing a receive simplex communication path and blocking half duplex communications therethrough; and

    a circuit coupled to one of the two pads to detect effects of the load modulation circuitry, and to drive a signal on to the coil to provide a transmit simplex communication path to restore the half duplex communications.

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