Wireless powered communication device with adaptive data detection and method

• US 5,930,304 A
• Filed: 03/20/1997
• Issued: 07/27/1999
• Est. Priority Date: 03/20/1997
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Hollenbeck, Neal W., Paitl, Kenneth A., Lemersal, Donald B. Jr.
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): PARK, ALBERT C
• Application Number:
  US08/822,399
• Time in Patent Office: 859 Days
• Field of Search: 375/317, 375/320, 375/346, 375/352, 375/259, 375/316, 340/825.54, 340/825.34, 455/41, 379/55.1
• US Class Current: 375/316
• CPC Class Codes: G06K 13/077 with intermittent movement; Braking or stopping movement
• CPC Class Codes: H04L 25/062 Setting decision thresholds using feedforward techniques only
• CPC Class Codes: H04L 27/06 Demodulator circuits; Receiver circuits

Abstract

The present invention expands the range over which a wireless powered communication device (500) and device reader (12) can communicate. In the present invention, circuitry (502) within the device (500) provides for determining a characteristic of the received communication signal. Based upon this signal characteristic data recovery parameters are adapted to enhance data recovery over a maximize communication distance. In a preferred embodiment of the present invention, the magnitude of the power signal is observed. It is known that the power signal varies as an inverse square of the distance of the device (500) to the reader. From this information, a data detection threshold is adjusted to enhance data recovery.

Claims

1. In a wireless powered communication apparatus having a power coil and a data coil and wherein a receiver station provides a power signal at a power carrier frequency and a modulated data signal containing a data signal modulated at a data carrier frequency, the wireless powered communication apparatus being adapted to receive the power signal from the power coil and the modulated data signal from the data coil, a method for recovering the data signal from the modulated data signal comprising the steps of:

generating a power source from the power signal;

applying the power source to a data recovery circuit;

sampling the modulated data signal within the data recovery circuit to recover the data signal;

detecting a characteristic of the power signal present in the modulated data signal, the modulated data signal being received by the data coil; and

adjusting a data recovery parameter of the data recovery circuit in response to the characteristic.

2. The method of claim 1 wherein the characteristic comprises a magnitude of the power signal.

3. The method of claim 1 wherein the data recovery parameter comprises one of:

a signal detection threshold, a gain, a filter parameter, a bias voltage value, and a signal detection characteristic detection parameter.

4. The method of claim 1 further comprising the step of modifying the data signal in response to the characteristic.

5. The method of claim 4 wherein the step of modifying the data signal comprises one of inhibiting a data transmission and initiating a data transmission.

6. A wireless powered communication apparatus having a power coil and a data coil and wherein a receiver station provides a power signal at a power carrier frequency and a modulated data signal containing a data signal modulated at a data carrier frequency, the wireless powered communication apparatus being adapted to receive the power signal from the power coil and the modulated data signal from the data coil, the wireless powered communication apparatus arranged for recovering the data signal from the modulated data signal, the wireless powered communication apparatus comprising:

generating means for generating a power source from the power signal;

applying means for applying the power source to a data recovery circuit;

sampling means for sampling the modulated data signal within the data recovery circuit to recover the data signal;

detecting means for detecting a characteristic of the power signal present in the modulated data signal, the modulated data signal being received by the data coil; and

adjusting means for adjusting a data recovery parameter of the data recovery circuit in response to the characteristic.

7. The wireless powered communication apparatus of claim 6 wherein the characteristic comprises a magnitude of the power signal.

8. The wireless powered communication apparatus of claim 6 wherein the data recovery parameter comprises one of:

a signal detection threshold, a gain, a filter parameter, a bias voltage value, and a signal detection characteristic detection parameter.

9. The wireless powered communication apparatus of claim 6 further comprising modifying means for modifying the data signal in response to the characteristic.

10. The wireless powered communication apparatus of claim 9 wherein the modifying means comprises one of means for inhibiting a data transmission and means for initiating a data transmission.

11. A wireless powered communication apparatus comprising:

a power coil for receiving a power signal at a power carrier frequency;

a data coil for receiving a modulated data signal containing a data signal modulated at a data carrier frequency;

a power generating circuit coupled to the power coil and further being coupled to a rectifier and a regulator providing a direct-current power supply;

a data recovery circuit coupled to the data coil, the data recovery circuit comprising a sampling circuit coupled to the data coil, the sampling circuit having a sampled data signal output;

an adjustable threshold detect comparator coupled to the sampling circuit and arranged to receive the sampled data signal output and having a modulated data signal output;

a demodulator coupled to receive the modulated data signal output and having a demodulated data signal output; and

a comparator threshold adjust circuit coupled to the adjustable threshold detect comparator and to the data coil, the comparator threshold adjust circuit being arranged for detecting a characteristic of the power signal present in the modulated data signal, the modulated data signal being received by the data coil.

12. The wireless powered communication apparatus of claim 11 wherein the comparator threshold adjust circuit comprises a power signal level detection circuit.

13. The wireless powered communication apparatus of claim 12 wherein the adjustable threshold detect comparator is adjusted in response to a magnitude of the power signal.

14. The wireless powered communication apparatus of claim 12 wherein the adjustable threshold detect comparator includes an adjusted operating parameter selected from the group of:

a signal detection threshold, a gain, a filter parameter, a bias voltage value, and a signal detection characteristic detection parameter.

15. The wireless powered communication apparatus of claim 12 wherein the comparator threshold adjust circuit comprises:

a power signal level comparator which compares a voltage level of the power signal present in the modulated data signal to a reference dc level, thus forming a power signal level comparator output, the modulated data signal being received by the data coil;

a first digital counter circuit which detects and counts transitions of the power signal level comparator output, thus forming a first count;

a second digital counter circuit which detects and counts transitions of the power signal, thus forming a second count, the power signal being received by the power coil,

a digital comparator which compares the first count to the second count, thus forming a digital comparator output; and

a control signal which determines the threshold of the adjustable threshold comparator based on the digital comparator output.

16. The wireless powered communication apparatus of claim 12 wherein the power signal level comparator employs a majority polling procedure to ensure that the power signal level comparator output is stable.