Apparatus for contactless energy and data transmission for single coil and two-coil systems

• US 5,473,323 A
• Filed: 11/30/1993
• Issued: 12/05/1995
• Est. Priority Date: 11/30/1992
• Status: Expired due to Fees

• Current Assignee: Angewandte Digital Electronik GmbH
• Original Assignee: Angewandte Digital Electronik GmbH
• Inventors: Kreft, Hans-Diedrich
• Primary Examiner(s): Peng, John K.
• Assistant Examiner(s): HILL, ANDREW M
• Application Number:
  US08/160,347
• Time in Patent Office: 735 Days
• Field of Search: 340/870.31, 340/870.3, 340/870.32, 340/825.34, 340/825.54, 340/825.7, 340/870.18, 340/870.25, 455/41, 455/42, 455/60, 235/380, 342/44, 342/51
• US Class Current: 340/10.34
• 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: G08C 17/04 using magnetically coupled devices
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence

Abstract

An inductor transmission path for energy and data from a write/read station onto, for example, a chip card is disclosed. A specific, vector-oriented phase modulation with two coils is disclosed, making it possible for the write/read station to use the same method to service different cards, i.e. those with one coil, or with a large coil or having two coils.

Claims

1. A method for contactless data and energy transmission between an immobile microstation having a coil pair and further having a means for providing an oscillating clock signal and a mobile microunit having either one or two coils, comprising the following steps:

a) receiving the clock signal by a phase modulator in the microstation and generating from the clock signal, a first and a second synchronous oscillating signals having the same frequency and phase-shifted by 90°

relative to each other by the phase modulator in said microstation;

b) assigning every phase switching of the synchronous oscillating signals to a logical signal level "high" or "low" of a data signal to be received by the phase modulator and transmitted to a microunit;

c) switching said phase-shifted synchronous oscillating signals by |90°

| by said phase modulator in a defined fashion depending on said data signal to be transmitted to a microunit, such that the phases of said synchronous oscillating signals do not oppositely cross during said switching and also do not become equiphase;

d) controlling a first amplifier and a first transformer coil of said coil pair on the microstation by said first synchronous oscillating signal and controlling a second amplifier and a second transformer coil of said coil pair on the microstation by said second synchronous oscillating signal so that said transformer coils generate respective first and second magnetic energy field signals having phase modulated information, and further coupling said magnetic energy field signals onto the either one or two coils of the microunit;

e) demodulating the phase modulated data and outputting data in the microunit;

f) transmitting data from said mobile microunit to said microstation by utilizing amplitude modulation caused by a load change at said one or two coils of said microunit, whereby said load change of said one or two coils of the mobile microunit can be identified by the amplitude modulation induced in the signal at the coupled one or both coils of said microstation;

g) summing with respect to time, the first and second signals of the two coils of the microstation to form a summation signal;

h) demodulating said summation signal by amplitude demodulation; and

i) outputing a logical digital data signal level.

2. The method of claim 1, wherein said coupling step is further defined by coupling a microunit having one coil onto one of said coils of said microstation.

3. The method of claim 1, wherein said coupling step is further defined by coupling a microunit having two geometrically separated reception coils onto both coils of the coil pair of said microstation to form two separate pairs of coupled coils.

4. The method of claim 1, wherein said coupling step is further defined by coupling a microunit having one large coil onto both of said coils of said microstation simultaneously, so that a canceling superposition of the induced voltage in said large coil is reduced by a limited phase difference between said transmitted synchronous oscillating signals.

5. The method of claim 1, further defined by enabling said data transmission from said microunit and from said microstation while having an arbitrary spatial operating position of said microunit relative to said microstation during demodulating the phase and/or amplitude modulated signal.

6. An apparatus for contactless data and energy transmission including,

a mobile microunit having either one or two coils and further comprising:

means for receiving and demodulating a phase modulated information signal and outputting data;

means for sending data by load modulation of the one or two coils of the microunit;

an immobile microstation having a coil pair and a means for providing an oscillating clock signal utilized for generating a first and a second synchronous oscillating signals of equal frequency and phase-shifted by 90°

from each other, so that data transmission from microstation to microunit occurs by switching the phase-shifting of the first and second synchronous oscillating signals, said microstation further comprising;

data signal providing means for providing a data signal to be transmitted to a microunit;

phase modulator means for generating the first and second synchronous oscillating signals from the clock signal and for switching the phase of the two synchronous oscillating signals by |90°

| depending on a logic level of said data signal, such that the phases of said oscillations do not oppositely cross during the switching and also do not become equiphase;

first amplifier means having an input coupled to receive said first synchronous oscillating signal and an output coupled to a first transformer coil of said coil pair of said microstation for generating a first magnetic energy field signal and for transmitting a phase modulated information signal;

second amplifier means having an input coupled to receive said second synchronous oscillating signal and an output coupled to a second transformer coil of said coil pair of said microstation for generating a second magnetic energy field signal and for transmitting a phase modulated information signal;

means for coupling said first and second magnetic energy field signals thereby transmitting phase modulated information onto said one or two coils of the microunit;

means for summing with respect to time, the first and second signals of the two coils of the microstation to form a summation signal; and

amplitude demodulator means for demodulating said summation signal and outputting data transmitted by the microunit, resulting from a load change at said one or two coils of said microunit, from said microunit to said microstation.

7. The apparatus of claim 6, wherein said microunit has two geometrically separated coils for coupling with the pair of said coils of said microstation to form two separate pairs of coupled coils whereby said coupling of said pairs is arbitrary.

8. The apparatus of claim 6, wherein said microunit has one coil for coupling onto one of said microstation coils whereby said coupling is arbitrary.

9. The apparatus of claim 6, wherein said microunit has one large coil for simultaneously coupling onto both of said microstation coils, whereby a canceling superposition of the induced voltage in said one large coil is reduced by a limited phase difference between said transmitted synchronous oscillating signals.