Data detection, power transfer and power regulation for data storage devices
First Claim
1. Apparatus for communicating with a data-storing device in a contactless manner, the apparatus comprising a resonant circuit having an inductive component which is arranged for inductive coupling to an inductor in the device for delivering power to the device, data detection means coupled to the resonant circuit for sensing changes in the combined impedances of the resonant circuit and the device to detect data transmitted by changes in the impedance of the device, and means for supporting the device such that the inductances of the apparatus and the device are separated by a distance D, wherein D can vary from a minimum of D1, wherein the impedance of the resonant circuit Zi =Ri +jXi, wherein the reflected impedance of the device in the resonant circuit Zt =Rt +jXt, and wherein, when D=D1, Rt >
- Ri.
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Accused Products
Abstract
Apparatus for delivering power to and communicating with a data-storing device, e.g. a token, in a contactless manner includes a resonant circuit arranged for inductive coupling with the device. The values of the components are selected to give a relatively constant power transfer over the possible range of distances between the inductances. Communications from the device resulting in changes in the token impedance are detected by sensing current changes in the resonant circuit. The power transmitted by the resonant circuit is limited to prevent excessive power damaging devices whose characteristics are such that they may be damaged by higher power levels. Devices which require higher levels can send a signal which results in the limit being bypassed.
103 Citations
32 Claims
- 1. Apparatus for communicating with a data-storing device in a contactless manner, the apparatus comprising a resonant circuit having an inductive component which is arranged for inductive coupling to an inductor in the device for delivering power to the device, data detection means coupled to the resonant circuit for sensing changes in the combined impedances of the resonant circuit and the device to detect data transmitted by changes in the impedance of the device, and means for supporting the device such that the inductances of the apparatus and the device are separated by a distance D, wherein D can vary from a minimum of D1, wherein the impedance of the resonant circuit Zi =Ri +jXi, wherein the reflected impedance of the device in the resonant circuit Zt =Rt +jXt, and wherein, when D=D1, Rt >
- 6. Apparatus for communicating with a data-storing device in a contactless manner, the apparatus comprising a resonant circuit having an inductive component which is arranged for inductive coupling to an inductor in the device for delivering power to the device, data detection means coupled to the resonant circuit for sensing changes in the combined impedances of the resonant circuit and the device to detect data transmitted by changes in the impedance of the device, and means for supporting the device such that the inductances of the apparatus and the device are separated by a distance D, wherein D can very to a maximum of D2, wherein the impedance of the resonant circuit Zi =Ri +jXi, wherein the reflected impedance of the device in the resonant circuit Zt l=Rt +jXt, and wherein, when D=D2, Rt >
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11. Apparatus for communicating with a data-storing device in a contactless manner, the apparatus comprising a resonant circuit having an inductive component which is arranged for inductive coupling to an inductor in the device for delivering power to the device, a current limiting means for controlling the power at which the resonant circuit is driven to prevent excessive power transfer to the data storing device, wherein said current limiting means has a slow response time permitting short term power changes.
- 12. Apparatus for communicating with a data-storing device in a contactless manner, the apparatus comprising a resonant circuit having an inductive component which is arranged for inductive coupling to an inductor in the device for delivering power to the device, means for controlling the power at which the resonant circuit is driven to prevent excessive power transfer to a data storing device, and means for overriding the power control.
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16. Apparatus for delivering power in a contactless manner to a data-storing device and for receiving data from the device, the apparatus being responsive to a predetermined signal from the device for increasing the power supplied thereto.
- 17. A data-storing device having power level sensing means, and means responsive thereto for generating a signal indicating that further power to the device is required.
Specification