Method and system for contactless energy transmission and data exchange between a terminal and IC card

• US 6,173,899 B1
• Filed: 04/03/1998
• Issued: 01/16/2001
• Est. Priority Date: 04/03/1998
• Status: Expired due to Fees

• Current Assignee: Alexander Rozin
• Original Assignee: Alexander Rozin
• Inventors: Rozin, Alexander
• Primary Examiner(s): Hajec, Donald
• Assistant Examiner(s): Lee, Diane I.
• Application Number:
  US09/054,543
• Time in Patent Office: 1,019 Days
• Field of Search: 235/492, 235/449, 235/451, 235/382, 902/26
• 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 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/07777 the antenna being of the inductive type
• CPC Class Codes: G06K 19/07788 the antenna being of the capacitive type
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: H01F 2038/146 in combination with capacitive coupling

Abstract

The present invention relates to methods and systems for power and energy transfer for non-contact IC cards, which is capable to communicate with an external device such as a host terminal. The disclosed method and system give the possibility to combine inductive coupling for remote power and data transmission, and capacitive coupling while IC card is attached to terminal, in order to transfer a large amount of energy. The new in the art is that bidirectional data and energy transfer from a terminal into an IC card is performing at two different carrier frequencies of an energy-transmitting alternating field. Herein the remote data transmission and energy transfer into the IC card is provided at first, lowest, frequency, utilizing the inductive coupling between a terminal transmitting-receiving coil and a IC card transmitting-receiving coil. Additionally, the close contactless energy and data transmission into the IC card is provided at second, higher, frequency utilizing the capacitive coupling between a terminal and IC card capacitive pads while IC card is attached to the terminal. The first frequency is designed to be a frequency of a parallel resonance combined by parallel alignment of an IC card inductive coil and a distributed capacitance of an IC card capacitive pads. The second frequency is designed to be a frequency of a series resonant circuit associated with series alignment of additional terminal inductance and joint capacitance of a terminal capacitive pads and IC card capacitive pads, when card is attached to terminal.

Claims

1. A method for contactless energy transmission and data exchange between a host terminal and integrated circuit IC card, which is powered via an energy-transmitting alternating field at a different frequencies which are modulated with data signal to provide bidirectional data transfer, comprising the steps of:

the remote bidirectional data transmission and energy transfer into the IC card at first, lowest frequency, utilizing the inductive coupling between a terminal transmitting-receiving coil and an IC card transmitting-receiving coil while IC card is separated from terminal,

the close coupling bidirectional data transmission and energy transfer into the IC card at second frequency, higher than first frequency, utilizing the galvanically contactless capacitive coupling between terminal capacitive pads and IC card capacitive pads while IC card is attached closely to the terminal,

wherein first frequency is designed to be a frequency of a parallel resonant circuit combined by parallel alignment of an IC card inductive coil and a distributed capacitance of IC card capacitive pads,

wherein second frequency is designed to be a frequency of a series resonant circuit associated with additional inductor of terminal and joint capacitance of a terminal capacitive pads with the IC card capacitive pads, when card is attached closely to terminal, and

the second frequency is selected to be as higher than first frequency where an equivalent impedance of IC card inductive coil is significantly large to load the series resonant circuit combined by serial alignment of joint capacitance created by mating of terminal capacitive pads with IC card capacitive pads with an additional inductance of terminal when IC card is attached closely to terminal.

2. A method for contactless energy transmission and data exchange of claim 1, comprising:

step of selecting clock signal from carrier frequency of energy-transmitting alternating field and step of generating enable and disable signals for elements of IC card in order to provide correct card operation while power induced into the card changes,

wherein clock rate is normalized to have a constant value to provide stable operation and timing of microprocessor and memory arranged at IC card, wherein the procedure of normalization and stabilization of clock rate is controlled by means of changing the dividing ratio factor of carrier frequency of energy-transmitting alternating field,

wherein procedure of changing of said dividing ratio is based upon result of measuring of current amount induced into IC card, and

the procedure of generating enable and disable signals for elements of IC card is based upon result of measuring of current amount induced into IC card.

3. A system for contactless energy transmission and data exchange between a host terminal and IC card, which is powered via an energy-transmitting alternating field at a different frequencies which are modulated with data signal, wherein IC card containing first capacitive pads, diode bridge, voltage regulator with smoothing capacitor, data detector, clock conditioner and modulating means, microprocessor unit having internal memory, and additional nonvolatile memory, additionally comprising:

inductive coil for remote power receiving into the IC card at first, lowest frequency of energy-transmitting alternating field,

current detector and power switch that are designed to measure current induced into the IC card and further to generate control signal to enable/disable microprocessor unit and nonvolatile memory,

wherein first capacitive pads combine a distributed self-capacitance, and

the inductive coil of IC card combines parallel resonance circuit with distributed self-capacitance of first capacitive pads at first frequency.

4. A system for contactless energy transmission and data exchange of claim 3 containing the host terminal comprising second capacitive pads designed to combine associated joint capacitors with corresponding first capacitive pads of IC card when last is attached to terminal, an additional inductor connected in series alignment with one of second capacitive pads of terminal, and comprising:

antenna for power radiation and data transmission and receiving, which is operating at first frequency, and

said additional inductor combines a series resonance circuit with associated joint capacitors, when card is attached closely to terminal.

5. A system for contactless energy transmission and data exchange between a host terminal and IC card, which is powered via an energy-transmitting alternating field at a different frequencies which are modulated with data signal, which system containing:

the IC card comprising first capacitive pads, diode bridge, voltage regulator with smoothing capacitor, data detector, clock conditioner and modulating means, microprocessor unit having internal memory, and wherein IC card additionally comprising inductive coil,

the host terminal comprising second capacitive pads designed to combine associated joint capacitors with corresponding first capacitive pads of IC card when last is attached closely to terminal,

additional inductor connected in series alignment with one of second capacitive pads of terminal, and additionally host terminal comprising;

antenna for power radiation and data transmission and receiving at first, lowest frequency of energy-transmitting alternating field,

wherein the inductor of host terminal combines a series resonant circuit with associated joint capacitors fabricated by mating of second capacitive pads with corresponding first capacitive pads when IC card is attached closely to host terminal,

wherein first capacitive pads of IC card combine a distributed self-capacitance,

wherein the inductive coil of IC card combines a parallel resonant circuit with distributed self-capacitance of first capacitive pads of the IC card when card is separated from host terminal, and

wherein a frequency of series resonant circuit differs from frequency of parallel resonant circuit.

6. A system for contactless energy transmission and data exchange according claim 5, wherein a remote bidirectional data transmission and energy transfer by means of energy-transmitting alternating field from the host terminal to the IC card is provided at a first frequency which is designed to be equal to the frequency of a parallel resonant circuit combined by parallel alignment of the inductive coil and distributed self-capacitance when card is separated from host terminal,

a close coupling bidirectional data transmission and energy transfer by means of energy-transmitting alternating field from the host terminal to the IC card is provided at a second frequency equal to the frequency of a series resonant circuit combined by series alignment of the terminal inductor and associated joint capacitors, when IC card is attached closely to terminal, and

a second frequency is selected to be as higher than first frequency where an equivalent impedance of a said IC card inductive coil is significantly large to load the series resonant circuit combined by serial alignment of additional inductor of the terminal with associated joint capacitors fabricated by mating of second capacitive pads with corresponding first capacitive pads of IC card when card is attached closely to terminal.

7. A system for contactless energy transmission and data exchange of claim 5, comprising IC card containing:

current detector, designed to measure the amount of electric current transferred into the IC card, and wherein the current detector is coupled with voltage regulator'"'"'s output in order to measure the magnitude of flowing current,

wherein output of current detector is connected with power switch, which is coupled correspondingly by first output to nonvolatile memory, by second output with microprocessor, and by third output with control input of clock conditioner, which is designated to select clock signal from carrier frequency of energy-transmitting alternating field and to control the dividing ratio factor of input frequency in order to provide a constant clock rate for stable operation and timing of microprocessor and nonvolatile memory arranged at IC card,

wherein the setup of dividing ratio factor of input frequency is provided according to the output signal of power switch, which signal is based upon result of measuring of induced current magnitude value flowing into IC card, and

the outputted signal of power switch generates enable/disable signals for microprocessor and nonvolatile memory to provide the proper power distribution in IC card while power amount induced into the card changes.