Bidirectional inductive transmission of data with slave station supplied by the master

• US 5,260,701 A
• Filed: 08/22/1991
• Issued: 11/09/1993
• Est. Priority Date: 01/19/1990
• Status: Expired due to Fees

• Current Assignee: Societe Bertin & Cie Co.
• Original Assignee: Societe Bertin & Cie Co.
• Inventors: Dubujet, Bruno, Ayraud, Michel, Guern, Yves
• Primary Examiner(s): Peng, John K.
• Assistant Examiner(s): Gray, Robert
• Application Number:
  US07/752,656
• Time in Patent Office: 810 Days
• Field of Search: 340/825.54, 340/870.31, 340/870.32, 340/870.33, 340/870.34, 340/870.35, 340/870.36, 340/825.72, 128/419 PT, 128/903, 342/44, 342/51, 455/41, 455/83, 455/89, 455/88
• US Class Current: 340/10.34
• CPC Class Codes: A61N 1/37211 Means for communicating with stimulators
• CPC Class Codes: A61N 1/37223 Circuits for electromagnetic coupling
• CPC Class Codes: A61N 1/3727 characterised by the modulation technique
• CPC Class Codes: H04B 5/00 Near-field transmission systems, e.g. inductive or capacitive transmission systems
• CPC Class Codes: H04B 5/22 Capacitive coupling
• CPC Class Codes: H04B 5/77 for interrogation
• CPC Class Codes: H04L 5/143 for modulated signals H04L5/1469 takes precedence

Abstract

A device for the bi-directional transmission of data between a master system and a slave system uses a single transmission antenna and a single reception antenna each tuned to the same frequency; the master system comprises first data transmission circuits for transmitting first data to the slave system by modulating an electromagnetic signal at the frequency; detection circuits for detecting, during the transmission of the electromagnetic signal, variations in electrical characteristics of the master system induced by a modulation of the impedance of the slave system as a function of second data to be transmitted from the slave system to the master system; and restoring circuits for restoring the second data on the basis of the detected variations; and the slave system comprises reception circuits connected to the reception antenna for restoring the first data; a rectifier circuit connected across the reception antenna for rectifying an electrical signal induced in the reception antenna by the electromagnetic signal; a power supply circuit connected to the rectifier circuit for powering the circuits and the loads of the slave system with a DC voltage on the basis of energy from the rectified electrical signal; and a switching circuit connected in series between the rectifier circuit and the power supply circuit to modulate the real part of the impedance of the slave system between a high value and a low value when the switching circuit is driven in its opened and closed position by a control signal representative of the second data.

Claims

1. A device for the bi-directional transmission of data between a master system and a slave system, comprising:

a single transmission antenna and a single reception antenna each tuned to the same frequency;

said master system comprises first data transmission means for transmitting first data to said slave system by modulating an electromagnetic signal at said frequency;

detection means for detecting, during said transmission of said electromagnetic signal, variations in electrical characteristics of said master system induced by a modulation of the impedance of said slave system as a function of second data to be transmitted from said slave system to said master system; and

restoring means for restoring said second data on the basis of said detected variations; and

said slave system comprises reception circuit means connected to said reception antenna for restoring said first data;

a rectifier circuit connected across said reception antenna for rectifying an electrical signal induced in said reception antenna by said electromagnetic signal;

a power supply circuit connected to said rectifier circuit for powering the circuits and the loads of said slave system with a DC voltage on the basis of energy from said rectified electrical signal; and

a switching circuit connected in series between said rectifier circuit and said power supply circuit to modulate the real part of the impedance of said slave system between a high value and a low value when said switching circuit is driven in its opened and closed position by a control signal representative of said second data.

2. A device according to claim 1, wherein said power supply circuit includes the combination of a series diode and a parallel capacitor.

3. A device according to claim 1, wherein said detection means include means of detecting variations in the electrical power consumed by said transmission antenna.

4. A device according to claim 1, wherein said detection means include means of detecting variations in the current/voltage phase lag in the transmission antenna.

5. A device according to claim 1, wherein said slave system constitutes an active electronic device which can be implanted in a human or animal body.

6. A device according to claim 1, wherein said switching circuit comprises a first transistor having an emitter-collector path connected in series between said rectifier circuit and said power supply circuit;

a first polarization resistor connected between the base of said first transistor and said rectifier circuit; and

a second polarization resistor connected between said base and ground.

7. A device according to claim 6, wherein said switching circuit further comprises a second transistor having a drain-source path connected in series between said second resistor and ground and receiving on the grid thereof said control signal.