ANALOG COMPENSATOR CIRCUIT TO COMPENSATE FOR CABLE LOSS

• US 20130257404A1
• Filed: 03/29/2013
• Published: 10/03/2013
• Est. Priority Date: 03/30/2012
• Status: Active Grant

• Current Assignee: CHECKPOINT SYSTEMS, INC. (CCL Industries Incorporated)
• Original Assignee: CHECKPOINT SYSTEMS, INC. (CCL Industries Incorporated)
• Inventors: McMahon, Michael T.
• Granted Patent: US 9,104,224 B2
• Time in Patent Office: Days
• US Class Current: 323/293
• CPC Class Codes: G05F 1/656 using variable impedances in series and in parallel with the load as final control devices
• CPC Class Codes: H02M 1/0025 Arrangements for modifying reference values, feedback values or error values in the control loop of a converter
• CPC Class Codes: H04L 12/10 Current supply arrangements

Abstract

Apparatus, systems and methods for correcting data received from a power cable is presented. A method receives communication data from a near end of a cable that has near and far ends. The data is compared using hysteresis to a high threshold and/or a low threshold. The data is reset to produce corrected data by resetting the data to either a high value or a low value based on the comparing. For example, when the corrected data is high, the data is reset to a low value when the communication data crosses the low threshold and when the corrected data is low, the data is reset to a high value when the communication data crosses the high threshold. The corrected data can provide a power supply data needed so that it can more accurately provide a power through the cable to the far end of the cable.

Claims

1. A system comprising:

comparator logic circuitry configured to compare a received communication signal to a reference signal, wherein the received communication signal is received from a power cable;

amplification logic circuitry configured to amplify the received communication signal and output a corrected output signal, wherein the corrected output signal is set high in response to the received communication signal being greater than the reference signal and wherein the corrected output signal is set low in response to the received communication signal being less than the reference signal; and

a power supply configured to decode the corrected output signal and adjust a power output to the power cable.

2. The system of claim 1 further comprising:

a display stand configured to display and secure a merchandise item that is connected at one end of the power cable and wherein the power supply is connected to another end of the cable,

3. The system of claim 1 further comprising:

biasing elements configured to create hysteresis between the reference signal and the received communication signal.

4. The system of claim 2 wherein the comparator logic circuitry is configured to operate with respect to:

a low threshold, wherein when the corrected output signal is high, the amplification logic circuitry is configured not to change the corrected output signal to a low value until the received communication signal goes below the low threshold; and

a high threshold, wherein when the corrected output signal is low, the amplification logic circuitry is configured not to change the corrected output signal to a high value until the received communication signal goes below the high threshold.

5. The system of claim 4 wherein the low threshold and the high threshold are separated by at least one volt.

6. The system of claim 1 wherein the comparator logic circuitry comprises an operational amplifier (op-amp).

7. The system of claim 1 further comprising:

a first pair of biasing resistors connected in series where the reference voltage is the voltage between the first pair of resistors; and

a second pair biasing resistors with feedback from the corrected output signal configured to bias the received communication signal.

8. The system of claim 1 wherein the power cable has a near end at the power supply and a far end;

and

wherein the system further comprises a transistor at the far end of the cable that is configured to create the received communication signal by inverting an original data signal transmitted from a microcontroller at the far end of the cable.

9. A system for supplying power to a cable comprising:

a cable with a near end and a far end;

a comparator located in the near end of the cable;

a controller located in the far end of the cable;

an inverting device;

a voltage input device at the far end of the cable to input a voltage into the controller;

a single communication wire located between the comparator and the inverting device;

a second wire between the inverting device and the controller; and

wherein the controller is configured to communicate data to the inverter that inverts the data to create inverted data, wherein the comparator is configured to compare the inverted data to at least one reference voltage and to generate corrected data based, at least in part, on the comparison of the inverted data to the at least one reference voltage, wherein the cable is configured to communicate the corrected data to a power supply at the near end of the cable so that the power supply can supply a power through the cable to the far end of the cable.

10. The system for supplying power to a cable of claim 9 further comprising:

biasing elements to create hysteresis between the inverted data and the at least one reference voltage.

11. The system for supplying power to a cable of claim 10 wherein the comparator is further configured to operate with respect to:

a low threshold, wherein when the corrected data is high, the comparator is configured to not allow the corrected data to go low until the inverted data goes below the low threshold; and

a high threshold, wherein when the corrected data is low, the comparator is configured to not allow the corrected data to go high until the inverted data goes below the high threshold,

12. The system for supplying power to a cable of claim 9 further comprising:

a low voltage dropout (LDO) regulator configured to stabilize the voltage at an analog-to-digital converter (ADC) in the controller.

13. The system for supplying power to a cable of claim 9 further comprising:

a Schottky diode and a capacitor configured to maintain a high voltage value when the single communication wire is driven low.

14. The system for supplying power to a cable of claim 9 further comprising:

a voltage measurement device at the far end of the cable configured to create a far end voltage value of a far end voltage at the far end of the cable, wherein the controller is configured to transmit the far end voltage value over the second wire between the inverting device and the controller and the single communication wire to the comparator, wherein the power supply is adapted to supply a power through the cable to the far end of the cable that is, at least in part, based on the far end voltage value.

15. The system for supplying power to a cable of claim 9 wherein the inverting device comprises a bipolar junction transistor (BJT) comprised of:

a gate connected to the second wire;

an emitter connected to the single communication wire; and

a collector connected to ground.

16. The system for supplying power to a cable of claim 9 wherein the comparator comprises an operation amplifier.

17. A method comprising:

receiving communication data from a near end of a cable that has a near end and a far end;

comparing the data using hysteresis to at least one of the group of;

a reference threshold, a high threshold, and a low threshold;

resetting the data to produce corrected data, wherein the resetting comprises resetting the data to a high value or a low value based, at least in part, on the comparing; and

wherein the corrected data can provide a power supply at least one parameter needed for supplying a power at the far end of the cable.

18. The method of claim 17 further comprising:

connecting the far end of the power cable to a merchandise item on display at a retail display and;

connecting the near end of the power cable to the power supply.

19. The method for correcting data received from a power cable of claim 17 wherein the resetting further comprises:

when the corrected data is high, resetting the data to a low value when the communication data crosses the low threshold; and

when the corrected data is low, resetting the data to a high value when the communication data crosses the high threshold.

20. The method for correcting data received from a power cable of claim 17 further comprising:

measuring a voltage at the far end of the cable, wherein the communication data represents, at least in part, the measured voltage.