# US 2019/0245385 A1 · Detuning for a resonant wireless power transfer system including cryptography

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2019/0245385 A1
- Document ID: US20190245385A1
- Status: Published application
- Kind: A1
- Application number: 15/892,158
- Filed: 2018-02-08
- Published: 2019-08-08
- Earliest claimed: 2018-02-08
- Assignees: Massachusetts Institute of Technology
- Applicants: Massachusetts Institute of Technology
- Inventors: Anantha P. Chandrakasan; Nachiket V. Desai; Chiraag Juvekar; Shubham Chandak
- Web page: https://patentgrep.com/patent/US20190245385A1

## CPC

- H02J 50/12: of the resonant type
- H02J 50/80: involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
- H02J 50/90: involving detection or optimisation of position, e.g. alignment
- H04L 9/006: {involving public key infrastructure [PKI] trust models (network architecture or network communication protocol for supporting authentication of entities using certificates in a packet data network H04L63/0823)}
- H04L 9/0662: {with particular pseudorandom sequence generator}
- H04L 9/3271: {using challenge-response}
- H04L 2209/80: Wireless
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

A method and apparatus for achieving detuning for a resonant wireless power transfer system including cryptography is described. Detuning for a resonant wireless power transfer system including cryptography allows for detuning a wireless receiver based upon authentication between the wireless receiver and a wireless charger.

## Claims

### Claim 1

A method for wireless power authentication comprising:
emitting an authentication challenge from a first inductive element to a wireless charger proximate to the wireless receiver;
validating a response from the wireless charger; and
adjusting a resonant frequency of the main inductive element according to the validated response.

### Claim 2 (depends on 1)

The method of claim 1, wherein the main inductive element is further configured to receive the response from the wireless charger.

### Claim 3 (depends on 1)

The method of claim 1, wherein the main inductive element is wirelessly coupled to an auxiliary inductive element.

### Claim 4 (depends on 1)

The method of claim 1, wherein adjusting the resonant frequency comprises:
adjusting an impedance presented to an auxiliary inductive element of the wireless receiver.

### Claim 5 (depends on 4)

The method of claim 4, wherein adjusting the impedance comprises:
determining a duty cycle based upon the validated response; and
adjusting a duty cycle of a rectifier coupled to the auxiliary inductive element according to the determined duty cycle.

### Claim 6 (depends on 4)

The method of claim 4, further comprising:
adjusting the impedance presented to the auxiliary inductive element to be effectively open when the response is valid.

### Claim 7 (depends on 4)

The method of claim 4, further comprising:
adjusting the impedance presented to the auxiliary inductive element to be effectively closed when the response is invalid.

### Claim 8 (depends on 1)

The method of claim 1, wherein a plurality of public keys is stored in the wireless receiver.

### Claim 9 (depends on 8)

The method of claim 8, wherein the response comprises a comparison of at least one of the plurality of public keys to a plurality of private keys.

### Claim 10 (depends on 1)

The method of claim 1, further comprising:
waiting for the response for a predetermined amount of time; and
emitting a second authentication challenge from the first inductive coil of the wireless receiver to the wireless charger after the predetermined amount of time has elapsed.

### Claim 11 (depends on 1)

The method of claim 1, wherein the wireless receiver further comprises an envelope detector.

### Claim 12 (depends on 11)

The method of claim 11, further comprising:
detecting an output signal of the envelop detector to determine that the wireless charger is within a range of the wireless receiver.

### Claim 13

A wireless power receiver for use within a wireless resonant inductive power transfer system, the wireless power receiver comprising:
a first inductive coil coupled to a digital authentication engine; and
a second inductive coil coupled to an auxiliary rectifier, wherein an impedance of the auxiliary rectifier is adjusted according to the digital authentication engine.

### Claim 14 (depends on 13)

The wireless power receiver of claim 13, wherein the first inductive coil is physically larger than the second inductive coil.

### Claim 15 (depends on 13)

The wireless power receiver of claim 13, wherein a resonant frequency of the first inductive coil is dependent upon the impedance of the auxiliary rectifier.

### Claim 16 (depends on 13)

The wireless power receiver of claim 13, wherein the first inductive coil is configured to emit an authentication challenge generated by the digital authentication engine.

### Claim 17 (depends on 13)

The wireless power receiver of claim 13, wherein the auxiliary rectifier is further coupled to a duty-cycle control circuit, wherein the duty-cycle control circuit is configured to adjust the duty cycle of the auxiliary rectifier.

### Claim 18 (depends on 17)

The wireless power receiver of claim 17, wherein the duty-cycle control circuit is configured to adjust the duty cycle of the auxiliary rectifier according to an acknowledgement generated by the digital authentication engine.

### Claim 19 (depends on 13)

The wireless power receiver of claim 13, wherein the digital authentication engine is configured to validate a response received at the first inductive coil.

### Claim 20 (depends on 13)

The wireless power receiver of claim 13, further comprising an envelope detector, wherein the envelope detector is configured to demodulate a response received at the first inductive coil.

### Claim 21 (depends on 13)

The wireless power receiver of claim 13, wherein the first inductive coil is one of a plurality of main inductive coils.

### Claim 22 (depends on 13)

The wireless power receiver of claim 13, wherein the second inductive coil is one of a plurality of auxiliary inductive coils.

### Claim 23 (depends on 21)

The wireless power receiver of claim 21, a resonant frequency of the first inductive coil is based upon at least one impedance presented to at least one of plurality of auxiliary coils.

### Claim 24 (depends on 13)

The wireless power receiver of claim 13, further comprising a communication engine configured to communicate to at least one other wireless power receiver.

### Claim 25 (depends on 13)

The wireless power receiver of claim 13, further comprising a main rectifier coupled to the first inductive coil.

### Claim 26 (depends on 25)

The wireless power receiver of claim 25, further comprising a load coupled to the main rectifier and the auxiliary rectifier, wherein the main rectifier and the auxiliary rectifier are configured to charge the coupled load.

### Claim 27 (depends on 26)

The wireless power receiver of claim 26, further comprising a communication engine, wherein the communication engine is configured to provide a power need of the load to at least one other wireless receiver.

### Claim 28 (depends on 27)

The wireless receiver of claim 27, wherein the at least one other wireless receiver is in proximity to a wireless charger.