DATA EXTRACTION THRESHOLD CIRCUIT AND METHOD

• US 20150171634A1
• Filed: 09/30/2014
• Published: 06/18/2015
• Est. Priority Date: 12/16/2013
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Neidorff, Robert A.
• Granted Patent: US 9,853,504 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H03K 19/20 characterised by logic function, e.g. AND, OR, NOR, NOT circuits H03K19/003 - H03K19/01 take precedence
• CPC Class Codes: H03K 2005/00078 Fixed delay
• CPC Class Codes: H03K 5/1532 Peak detectors measuring characteristics of individual pulses G01R29/02
• CPC Class Codes: H03K 5/1536 Zero-crossing detectors in measuring circuits G01R19/175
• CPC Class Codes: H03K 5/24 the characteristic being amplitude
• CPC Class Codes: H04B 5/0093 with one coil at each side, e.g. with primary and secondary coils
• CPC Class Codes: H04B 5/02 using transceiver
• CPC Class Codes: H04B 5/266 One coil at each side, e.g. with primary and secondary coils
• CPC Class Codes: H04B 5/48 Transceivers
• CPC Class Codes: H04B 5/72 for local intradevice communication
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

A circuit for setting a threshold level for extracting data from a signal stream includes a terminal couplable to the signal stream. A peak detector is coupled to the terminal. A valley detector is coupled to the terminal. A comparator is coupled to outputs of the peak detector and the valley detector for generating a threshold voltage for extracting data or commands from the signal stream. A method of extracting data from a signal stream including: peak detecting the signal stream to generate a first signal; valley detecting the signal stream to generate a second signal; combining the first and second signals to generate a threshold signal; and extracting data from the signal stream utilizing the threshold level signal.

Claims

1. A circuit for setting a threshold level for extracting data from a signal stream comprising:

a terminal couplable to the signal stream;

a peak detector coupled to the terminal;

a valley detector coupled to the terminal; and

a comparator coupled to outputs of the peak detector and the valley detector for generating a threshold voltage for extracting data or commands from the signal stream.

2. The circuit of claim 1 further comprising;

a first RC circuit coupled to the output of the peak detector; and

a second RC circuit coupled to the output of the valley detector.

3. The circuit of claim 2 wherein the first RC circuit comprises a first capacitor coupled between the output of the peak detector and ground and a first resistor coupled between the output of the peak detector and a node;

and

a second RC circuit comprises a second capacitor coupled between the output of the peak detector and ground and a second resistor coupled between the output of the peak detector and the node, wherein a signal at the node is a threshold level signal.

4. The circuit of claim 3 wherein a first terminal of the comparator is coupled to the node.

5. The circuit of claim 4 wherein the second terminal of the comparator is coupled to the signal stream.

6. The circuit of claim 5 wherein the first terminal is the inverting input of the comparator and a second terminal is a non-inverting input of the comparator.

7. The circuit of claim 6 further comprising;

a first diode at the output of the peak detector and a second diode at the output of the valley detector, each conducting an opposite direction so that the first and second parallel RC circuits are isolated when no signal is received.

8. The circuit of claim 7 further comprising;

a data preamplifier coupled to receive the signal stream and the threshold signal and having an output coupled to a second terminal of the comparator.

9. A method of extracting data from a signal stream comprising:

peak detecting the signal stream to generate a first signal;

valley detecting the signal stream to generate a second signal;

combining the first and second signals to generate a threshold signal; and

extracting data from the signal stream utilizing the threshold level signal.

10. The method of claim 9 further comprising;

coupling a first RC filter to receive the first signal and a proximal end of a first resistor;

coupling a second RC filter to receive the second signal at a proximal side of a second resistor; and

combining the first and second signals at a node between the first and second resistors to generate the threshold level signal.

11. The method of claim 10 further comprising;

receiving the signal stream at a first terminal of a preamplifier;

coupling a second terminal of the preamplifier to the threshold signal; and

coupling an output of the preamplifier to one terminal of a comparator.

12. In a primary side wireless power transmitter for being inductively coupled to a secondary side wireless power receiver for supplying power to the wireless power receiver to power a load coupled to the wireless power receiver, a primary side controller receiving communications from the secondary side wireless power receiver through the inductive coupling, comprising:

a peak detector receiving a signal stream from the secondary side wireless power receiver;

a valley detector receiving a signal stream from the secondary side wireless power receiver; and

a comparator coupled to outputs of the peak detector and the valley detector for generating a threshold voltage for extracting data or commands from the signal stream.

13. The controller of claim 12 further comprising;

a first RC circuit coupled to the output of the peak detector; and

a second RC circuit coupled to the output of the valley detector.

14. The controller of claim 13 wherein the first RC circuit comprises;

a first capacitor coupled between the output of the peak detector and ground and a first resistor coupled between the output of the peak detector and a node;

a second RC circuit comprises a second capacitor coupled between the output of the peak detector and ground and a second resistor coupled between the output of the peak detector and the node, wherein a signal at the node is a threshold voltage signal.

15. The controller of claim 14 wherein a first terminal of the comparator is coupled to the node and wherein the second terminal of the comparator is coupled to the signal stream.

16. The controller of claim 15 wherein the first terminal is the inverting input of the comparator and a second terminal is a non-inverting input of the comparator.

17. The controller of claim 16 further comprising;

a first diode at the output of the peak detector and a second diode at the output of the valley detector, each conducting in opposite directions so that the first and second parallel RC circuits are isolated when no signal is received.

18. The controller of claim 17 further comprising;

a data preamplifier coupled to receive the signal stream and the threshold voltage signal and having an output coupled to the second terminal of the comparator.

19. A method of operating a primary side wireless power transmitter inductively coupled to a secondary side wireless power receiver for supplying power to the wireless power receiver to power a load coupled to the receiver comprising:

peak detecting a signal stream from the wireless power receiver to generate a first signal;

valley detecting the signal stream to generate a second signal;

generating a threshold voltage signal from the first and second signals; and

extracting data from the signal stream utilizing the threshold voltage signal.

20. The method of claim 19 further comprising;

coupling a first RC filter to receive the first signal at a proximal end of a first resistor;

coupling a second RC filter to receive the second signal at a proximal side of a second resistor; and

combining the first and second signals at a node between the first and second resistors to generate the threshold voltage signal.

21. The method of claim 20 further comprising;

receiving the signal stream at a first terminal of a preamplifier;

coupling a second terminal of the preamplifier to the threshold voltage signal; and

coupling an output of the preamplifier to one terminal of a comparator.

22. A circuit for setting a threshold level for extracting data from a signal stream comprising:

a terminal coupled to the signal stream;

a fast-attack, slow-decay filter coupled to the terminal;

a fast-decay, slow-attack filter coupled to the terminal;

a comparator coupled to the outputs of the fast-attack, slow-decay and fast-decay, slow-attack filters for extracting data or commands from the signal stream.