Batteryless wireless sensor system

Patent metadata

Field	Value
Publication number	US-11973512-B2
Application number	US-202318116486-A
Country	US
Kind code	B2
Filing date	Mar 2, 2023
Priority date	Feb 25, 2021
Publication date	Apr 30, 2024
Grant date	Apr 30, 2024

Abstract

A batteryless wireless sensor system includes a data acquisition system, a radio frequency (RF) transceiver, and a batteryless wireless sensor device. The RF transceiver is in communication with the data acquisition system, transmits a RF signal, and receives sensor data and provide the sensor data to the data acquisition system. The batteryless wireless sensor device includes a RF transmitter, an analog to digital converter (ADC), and a sensor. The batteryless wireless sensor harvests energy from the RF signal and generates a DC signal based on the energy harvested from the RF signal, powers up and operates the ADC and the sensor based on the DC signal, and generates sensor data. The batteryless wireless sensor then transmits the sensor data via the RF transmitter to the RF transceiver. In certain examples, the ADC is implemented as a current mode ADC.

First claim

What is claimed is:

1. A batteryless wireless sensor system, the system comprising:
data acquisition system;
a portable computing device that is associated with a user, in communication with the data acquisition system, and configured to:
transmit a radio frequency (RF) signal; and
receive sensor data; and

a batteryless wireless sensor device including an RF transmitter, an analog to digital converter (ADC), and a sensor, the batteryless wireless sensor device configured to:
harvest energy from the RF signal and generate a DC signal based on the energy harvested from the RF signal;
power up and operate the ADC and the sensor based on the DC signal;
generate the sensor data that is based on a sensor voltage of the sensor that corresponds to a condition associated with the user to which the sensor is exposed, wherein the sensor data is output from the ADC based on digital sampling of the sensor voltage of the sensor by the ADC, wherein the ADC is coupled to the sensor via a single line, and wherein the sensor voltage is based on charging of a capacitor of the ADC by a sensor current of the sensor and a digital to analog converter (DAC) output current from the ADC; and
transmit the sensor data via the RF transmitter to the portable computing device, wherein the portable computing device is configured to provide the sensor data to the data acquisition system.

2. The system of claim 1 , further comprising:
another batteryless wireless sensor device including another RF transmitter, another ADC, and another sensor, the another batteryless wireless sensor device configured to:
harvest other energy from the RF signal and generate another DC signal based on the other energy harvested from the RF signal;
power up and operate the another ADC and the another sensor based on the another DC signal;
generate other sensor data that is based on another sensor voltage of the another sensor that corresponds to another condition associated with the user to which the another sensor is exposed, wherein the other sensor data is output from the another ADC based on digital sampling of the another sensor voltage of the another sensor by the another ADC, wherein the another ADC is coupled to the another sensor via another single line, and wherein the another sensor voltage is based on charging of another capacitor of the another ADC by another sensor current of the another sensor and another DAC output current from the another ADC; and
transmit the other sensor data via the another RF transmitter to the portable computing device, wherein the portable computing device is configured to provide the another sensor data to the data acquisition system.

3. The system of claim 1 , wherein the portable computing device that is associated with the user is wearable on the user.

4. The system of claim 1 , wherein the portable computing device that is associated with the user is a social networking device, a gaming device, a cell phone, a smart phone, a digital assistant, a digital music player, a digital video player, a laptop computer, a handheld computer, a tablet, or a video game controller.

5. The system of claim 1 , wherein the batteryless wireless sensor device further comprising:
an RF receiver configured to receive the RF signal; and
a DC rectifier operably coupled to the RF receiver and configured to process the RF signal that is received by the RF receiver to generate the DC signal.

6. The system of claim 1 , wherein the batteryless wireless sensor device is configured to transmit the sensor data via the RF transmitter to the computing device via a wireless communication system that includes one or more of a cellular communication system, a Bluetooth communication system, a ZigBee communication system, or a wireless local area network (WLAN).

7. The system of claim 1 , wherein the RF signal includes a frequency within a frequency band designated for unlicensed operation by the US Federal Communications Commission (FCC).

8. The system of claim 1 , wherein the condition associated with the user corresponds to heart-rate, respiration, blood pressure, movement, or oxygen level.

9. The system of claim 1 , wherein the ADC further comprising:
the capacitor operably coupled to the sensor and configured to produce the sensor voltage based on charging by the sensor current and the DAC output current;
a comparator operably coupled and configured to:
receive the sensor voltage via a first input of the comparator;
receive a reference voltage via a second input of the comparator; and
compare the sensor voltage to the reference voltage to generate a comparator output signal;

a digital circuit operably coupled and configured to process the comparator output signal to generate a first digital output signal that is representative of a difference between the sensor voltage and the reference voltage;
memory that stores operational instructions;
one or more processing modules operably coupled to the digital circuit and the memory and configured to execute the operational instructions to process the first digital output signal to generate a second digital output signal that is representative of the difference between the sensor voltage and the reference voltage, wherein the second digital output signal includes a higher resolution than the first digital output signal; and
an N-bit digital to analog converter (DAC) that is operably coupled to the one or more processing modules and configured to generate the DAC output current based on the second digital output signal, wherein N is a positive integer, the DAC output current tracks the sensor current, and the sensor voltage tracks the reference voltage.

10. The system of claim 9 , wherein:
the comparator includes a sigma-delta comparator; and
the digital circuit includes a clocked flip flop.

11. The system of claim 9 , wherein a digital comparator includes both the comparator and the digital circuit, wherein the digital comparator operably coupled and configured to:
receive the sensor voltage via a first input of the comparator;
receive the reference voltage via a second input of the comparator; and
compare the sensor voltage to the reference voltage to generate the first digital output signal that is representative of the difference between the sensor voltage and the reference voltage.

12. The system of claim 9 further comprising:
a decimation filter coupled to the one or more processing modules and configured to process the second digital output signal to generate another digital output signal having a lower sampling rate and a higher resolution than the second digital output signal.

13. The system of claim 1 , wherein the ADC further comprising:
the capacitor operably coupled to the sensor and configured to produce the sensor voltage based on charging by the sensor current and the DAC output current;
an M-bit analog to digital converter (ADC) operably coupled and configured to:
receive the sensor voltage;
receive a reference voltage; and
compare the sensor voltage to the reference voltage and generate a first digital output signal that is representative of a difference between the sensor voltage and the reference voltage;

memory that stores operational instructions;
one or more processing modules operably coupled to the M-bit ADC and the memory and configured to execute the operational instructions to process the first digital output signal to generate a second digital output signal that is representative of the difference between the sensor voltage and the reference voltage, wherein the second digital output signal includes a higher resolution than the first digital output signal; and
an N-bit dig

Assignees

• Sigmasense Llc

Inventors

• Huynh Phuong

Classifications

• H03M1/46 Primary

  with digital/analogue converter for supplying reference values to converter · CPC title

• H02J50/001

  Energy harvesting or scavenging · CPC title

• H02J50/20

  using microwaves or radio frequency waves · CPC title

• H04B5/0037

  Electricity · mapped topic

• H04B5/02

  Electricity · mapped topic