Voltage overshoot protection
AssigneeCochlear Limited
InventorIbrahim Ibrahim
Life of this patent
Estimating the term…
Abstract
A transmission circuit for an RF inductive link, particularly for an implanted device such as a cochlear implant. In a preferred form, the transmission circuit 1 includes a transmitter coil 24 and a damping device, including an auxiliary coil 4 and switch 6. The switch is operated to close the coil circuit when data zeros are transmitted. This has the advantage of improving modulation depth without placing stress on the RF driver output switches.
Claims14
An RF transmission circuit for transmitting at least a data signal across an inductive link, said transmission circuit comprising:
- modulation means for modulating a high frequency carrier signal with the data signal to provide an output signal;
- and
- transmission means, including a transmission coil, for transmitting the output signal across the inductive link,
- wherein said transmission means includes an output signal damping means that is selectively operable according to the value of the data signal, wherein the damping means comprises:
- an auxiliary coil;
- and
- a switch in parallel with the auxiliary coil;
- and
- wherein RF transmission circuit is configured to open the switch in response to the value of the data signal being equal to a first value and close the switch in response to the value of the data signal being equal to a second value.
An RF transmission circuit for a cochlear implant system, said transmission circuit comprising:
- modulating means for modulating a high frequency carrier signal with a serial data stream for transmission to an implanted stimulation device;
- and
- a headset coil for transmitting an output signal from said modulating means across a transcutaneous inductive link for detection by an implanted receiver coil;
- wherein said circuit further comprises a damping means that is selectively operable according to a momentary value of the serial data stream;
- and
- wherein the damping means comprises:
- an auxiliary coil;
- and
- a switch in parallel with the auxiliary coil;
- and
- wherein RF transmission circuit is configured to open the switch in response to the value of the data signal being equal to a first value and close the switch in response to the value of the data signal being equal to a second value.
A method of transmitting a stream of binary data across an inductive link, said method comprising the steps of:
- modulating a high frequency carrier signal with the data to provide an output signal;
- and
- transmitting said output signal across the inductive link;
- wherein said transmitting step includes the sub-step of selectively damping said high frequency carrier signal according to a momentary value of the binary data;
- wherein the sub-step of selectively damping comprises:
- opening a switch in response to the value of the data signal being equal to a first value, and
- closing the switch in response to the value of the data signal being equal to a second value;
- and
- wherein the switch is in parallel with an auxiliary coil.
Dependencies are inferred from the claim text.