# US 11,309,738 B2 · Recovery of modulation amplitude in wireless charger tx demodulation

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- Number: US 11,309,738 B2
- Document ID: US11309738B2
- Status: Granted
- Kind: B2
- Application number: 16/052,492
- Filed: 2018-08-01
- Published: 2020-02-06
- Granted: 2022-04-19
- Earliest claimed: 2018-08-01
- Assignees: Integrated Device Technology, Inc.
- Applicants: Integrated Device Technology, Inc.
- Inventors: Yue Wang; Lijie Zhao
- Web page: https://patentgrep.com/patent/US11309738B2

## CPC

- H02J 50/80: involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
- H02J 50/12: of the resonant type
- H04B 5/24: Inductive coupling
- H04B 5/266: {One coil at each side, e.g. with primary and secondary coils}
- H04B 5/79: for data transfer in combination with power transfer
- H04B 5/45: Transponders
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H04B: TRANSMISSION

## Abstract

In accordance with aspects of the present invention, a method and apparatus for demodulating an amplitude-modulated wireless power signal is presented. A method of receiving an amplitude modulated component of a wireless power transmission signal according to some embodiments includes receiving an input signal, wherein the input signal is based on an amplitude modulated wireless power signal; and applying an offset to the input signal to receive the amplitude modulated component. A demodulator according to some embodiments can include a first voltage-to-current converter that receives an input signal related to an amplitude modulated wireless power signal; a second voltage-to-current converter that receives an offset signal; and a summing node that adjusts a first current produced by the first voltage-to-current converter by a second current produced by the second voltage-to-current converter to produce an output signal.

## Claims

### Claim 1

A method of receiving an amplitude modulated component of a wireless power transmission signal, comprising;
receiving an input signal by converting the input signal to an input current signal, wherein the input signal is based on the amplitude modulated wireless power signal of the wireless power transmission signal;
applying an offset to the input signal to produce an output signal, wherein applying an offset includes converting an offset voltage to an offset current and subtracting the offset current from the input current signal to create the output signal such that the output signal is primarily an amplitude modulation portion of the amplitude modulated wireless power signal; and
processing the output signal to receive the amplitude modulated component, wherein processing the output signal includes converting the output current signal to a voltage output signal representing the amplitude modulated component, wherein a modulation amplitude of the voltage output signal is greater than a modulation amplitude of the input signal.

### Claim 2 (depends on 1)

The method of claim 1, wherein processing the output signal further includes providing peak detection to the voltage output signal to provide a data signal.

### Claim 3 (depends on 1)

The method of claim 1, wherein receiving the input signal includes
receiving the wireless power transmission signal; and
attenuating the wireless power transmission signal to form the input signal.