Integrated phase-shift power control transmitter for use with implantable device and method for use of the same

• US 20060184213A1
• Filed: 02/15/2005
• Published: 08/17/2006
• Est. Priority Date: 02/15/2005
• Status: Active Grant

• Current Assignee: Advanced Bionics LLC (Sonova Holding AG)
• Original Assignee: Advanced Bionics LLC (Sonova Holding AG)
• Inventors: Griffith, Glen A.
• Granted Patent: US 8,027,732 B2
• Time in Patent Office: Days
• US Class Current: 607/60
• CPC Class Codes: A61N 1/36038 Cochlear stimulation
• CPC Class Codes: A61N 1/3727 characterised by the modulation technique

Abstract

Systems and methods for efficiently transmitting power using a high frequency (e.g., RF) telemetry transmitter are provided. The telemetry transmitter may include a fixed clock source (which may provide a fixed clock signal), telemetry phase shift circuitry (which may include switching circuitry and phase shifting circuitry), and a push-pull network. The telemetry phase shift circuitry generates a phase shifted clock signal that is phase shifted with respect to the fixed clock signal. The fixed and phase shifted clock signals may drive the switching circuitry to produce a high frequency signal that is passed through the push-pull network. The power or magnitude of the high frequency signal is based on the phase delay between the fixed clock signal and the phase shifted clock signal.

Claims

1. Circuitry for controlling the power level of a sinusoidal signal being transmitted to a remote implanted device, comprising:

clock circuitry that generates a predetermined frequency clock signal;

a push-pull network; and

telemetry phase shift circuitry coupled to said clock circuitry and said push-pull network that generates a phase delayed clock signal, which is based on said predetermined frequency clock signal, and that generates said sinusoidal signal in response to said phase delayed and predetermined frequency clock signals, wherein the power level of said sinusoidal signal is based on a phase delay between said phase delayed clock signal and said predetermined frequency clock signal.

2. The circuitry of claim 1, wherein said telemetry phase shift circuitry comprises:

a variable voltage delay circuit coupled to receive said predetermined frequency clock signal and a DELAY CONTROL signal and operative to phase delay said predetermined frequency clock signal based on said DELAY CONTROL signal to provide said phase delayed clock signal.

3. The circuitry of claim 2, wherein said phase shift is proportional to the voltage of said DELAY CONTROL signal.

4. The circuitry of claim 1, wherein said telemetry phase shift circuit comprises:

a first amplifier coupled to said push-pull network that is selectively driven HIGH and LOW by said predetermined frequency clock signal; and

a second amplifier coupled to said push-pull network that is selectively driven HIGH and LOW by said phase delayed clock signal;

wherein the HIGH/LOW driving action of said first and second amplifiers generates said sinusoidal signal.

5. The circuitry of claim 1, wherein said push-pull network rejects higher order harmonics of said sinusoidal signal.

6. The circuitry of claim 4, wherein said push-pull network comprises a transformer;

wherein a differential voltage signal exist across said transformer when said first amplifier is driven HIGH and said second amplifier is driven LOW and when said first amplifier is driven LOW and said second amplifier is driven HIGH.

7. The circuitry of claim 1, wherein said phase delay ranges between −

180° and

180°

.

8. The circuitry of claim 1, wherein said clock circuitry selectively varies the frequency of said predetermined frequency clock signal.

9. A method for controlling a power level of a high frequency signal being transmitted to an implanted remote receiver, said method comprising:

providing a predetermined frequency clock signal;

generating a phase delayed clock signal which is phase delayed from said predetermined frequency clock signal by a predetermined phase delay; and

driving a first amplifier with said predetermined frequency clock signal and a second amplifier with said phase delayed clock signal to produce said high frequency signal having said power level based on said predetermined phase delay.

10. The method of claim 9, further comprising:

varying said predetermined phase delay to adjust said power level of said high frequency signal.

11. The method of claim 9, further comprising:

filtering out higher order harmonics of said high frequency signal, while passing the fundamental frequency of said high frequency signal.

12. The method of claim 9, further comprising:

transmitting said high frequency signal to said implanted remote receiver.

13. The method of claim 9, further comprising:

modulating said predetermined frequency clock signal with data in accordance with a selected modulation signal to produce a modulated frequency clock signal representing data to be transmitted to said implanted remote receiver.

14. A cochlear implant system comprising an external part and an implant part, the implant part having an implantable receiver circuit for generating and applying a stimulation current to a selected pair of implantable electrodes, the external part having an RF telemetry transmitter for transmitting power and data to the implant part, the RF telemetry transmitter comprising:

a clock source that provides a variable frequency clock signal;

a phase shifting circuit for generating a phase shifted clock signal which is phase shifted relative to said variable frequency clock signal by a predetermined phase delay;

switching circuitry responsive to said variable frequency clock signal and said phase shifted clock signal to selectively apply signals to a network, the application of which produces a high frequency signal; and

an output node that receives said high frequency signal.

15. The system of claim 14, wherein the power level of said high frequency signal is based on said predetermined phase delay.

16. The system of claim 14, wherein said predetermined phase delay ranges from −

180°

to 180°

.

17. The system of claim 14, wherein said phase shift circuit receives a DELAY CONTROL signal that sets said predetermined phase delay.

18. The system of claim 14, further comprising:

control circuitry coupled to said clock source and said phase shifting circuit, said control circuitry operative to;

provide a DELAY CONTROL signal to said phase shifting circuit; and

provide a modulation signal comprising data to be transmitted to said implant part, wherein said modulation signal modulates said variable frequency clock signal to incorporate said data into said high frequency signal.

19. The system of claim 14, wherein said network is a push-pull network comprising a transformer, and wherein said switching circuitry comprises:

a first switch responsive to said fixed clock signal to apply a first switch signal to a first node of said transformer; and

a second switch responsive to said phase shifted clock signal to apply a second switch signal to a second node of said transformer,

wherein the application of said first and second switch signals may cause a differential voltage to exist across said transformer.

20. The system of claim 14, further comprising:

an antenna coil coupled to said output and transmits said power signal to said implant part.