System and method for powering, controlling, and communicating with multiple inductively-powered devices

• US 6,345,203 B1
• Filed: 11/09/1999
• Issued: 02/05/2002
• Est. Priority Date: 06/09/1998
• Status: Expired due to Term

• Current Assignee: North Carolina State University (University of North Carolina System)
• Original Assignee: North Carolina State University (University of North Carolina System)
• Inventors: Nagle, H. Troy, Kelley, Arthur W., Mueller, Jeffrey S., Gyurcsik, Ronald S.
• Primary Examiner(s): Schaetzle, Kennedy
• Application Number:
  US09/436,674
• Time in Patent Office: 819 Days
• Field of Search: 607/60, 607/61, 607/2, 607/32, 607/33, 128/903, 332/149, 340/870.01, 340/870.18, 340/870.32, 340/573.1, 340/870.11, 340/825.69, 340/10.34
• US Class Current: 607/60
• CPC Class Codes: A61N 1/3787 from an external energy source
• CPC Class Codes: H02J 2310/23 The load being a medical device, a medical implant, or a life supporting device
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H02J 7/025 using non-contact coupling, e.g. inductive, capacitive

Abstract

Magnetic Vector Steering (MVS) and Half-Cycle Amplitude Modulation (HCAM) are novel techniques which enhance the powering and control of multiple arbitrarily oriented implant devices. Together, these techniques enable arbitrarily oriented implants to receive power and command, programming, and control information in an efficient manner that preserves battery life and transmission time while reducing overall implant device bulk. By steering the aggregate magnetic field from a near-orthogonal set of AC-energized coils, selected implants can be powered or communicated with at desired times. Communication with individual implants can also be enhanced through half-cycle amplitude modulation —a technique that allows bit rates up to twice the energizing frequency. Unlike prior art systems, power and data transfer can be realized over the same frequency channel.

Claims

1. An amplitude modulation method of transmitting data at up to two bits per cycle of a power carrier signal having two zero crossing points per cycle for use with inductively powered systems, said method comprising the steps of:

(a) detecting when the current through an energizing coil is zero;

(b) switching in or out a section of said energizing coil in order to modulate the magnetic field of said energizing coil at instants when the energizing coil current is zero; and

(c) replacing said switched energizing coil section with an equivalent inductance.

2. A amplitude modulation method of transmitting data at up to two bits per cycle of a power carrier signal having two zero crossing points per cycle for use with inductively powered systems employing advanced switching to compensate for inherent timing delays to establish a desired circuit path at the instance of the zero crossing state, said method comprising the steps of:

(a) switching in or out, in the opposite phase, a section of an energizing coil in order to modulate the magnetic field of said energizing coil prior to a zero crossing point; and

(b) replacing said switched energizing coil section with an equivalent inductance.