Circuit, system and/or method for detecting an electrical connection between an electrical device and a power supply

• US 20110084689A1
• Filed: 10/13/2009
• Published: 04/14/2011
• Est. Priority Date: 10/13/2009
• Status: Active Grant

• Current Assignee: Sennco Solutions Incorporated
• Original Assignee: Sennco Solutions Incorporated
• Inventors: Marszalek, Christopher, Horvath, Daniel, Groth, Jim, Berland, Kerry, Ty, Try, Kmiecik, Mark
• Granted Patent: US 9,019,113 B2
• Time in Patent Office: Days
• US Class Current: 324/119
• CPC Class Codes: G01R 31/50 Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections testing of sparking plugs H01T13/58
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults
• CPC Class Codes: G01R 31/54 Testing for continuity

Abstract

A circuit, a system and/or a method detect a passive electrical connection and/or an active electrical connection between an electrical device and a power supply. An integrity of the electrical connection between the electrical device and the power supply is monitored to determine if the electrical device may have access to power and/or to determine if the electrical device may be secure while on display. A high frequency AC signal is modulated onto a positive power rail between the electrical device and the power supply. Capacitance circuitry of the electrical device may remove the high frequency signal from the positive power rail. An absence of the high frequency signal on the positive power rail indicates that the electrical connection exists between the electrical device and the power supply. A presence of the high frequency signal on the positive power rail indicates that the electrical connection does not exist between the electrical device and the power supply.

Claims

1. A circuit for detecting an electrical connection between an electrical device and a power supply wherein the system modulates a high frequency signal onto a positive power rail between the electrical device and the power supply and further wherein the circuit monitors the positive power rail to determine if the high frequency signal is removed from the positive power rail by the electrical device, the circuit comprising:

a signal generation stage to generate the high frequency signal;

a modulation stage to connect the signal generation stage to the positive power rail to transmit the high frequency signal onto the positive power rail between the electrical device and the power supply;

a filter stage connected to the positive power rail to filter frequencies other than the high frequency signal from the positive power rail and to transmit the high frequency signal from the positive power rail; and

a rectifier stage to convert the high frequency signal transmitted from the positive power rail to a known DC level.

2. The circuit of claim 1 wherein the signal generation stage reduces a magnitude the high frequency signal.

3. The circuit of claim 1 further comprising:

a short circuit between the signal generation stage and the positive power rail.

4. The circuit of claim 1 further comprising:

an open circuit between the signal generation stage and the positive power rail.

5. The circuit of claim 1 further comprising:

a multi-feedback band-pass filter associated with the filter stage wherein the multi-feedback band-pass filter has an op-amp to pass a range of frequencies to the rectifier stage wherein the range of frequencies has a frequency of the high frequency signal.

6. The circuit of claim 1 further comprising:

a gain stage between the filter stage and the rectifier stage wherein the gain stage has an active gain-only op-amp to amplify a magnitude of the high frequency signal.

7. The circuit of claim 1 further comprising:

an active full-wave rectifier associated with the rectifier stage wherein the active full-wave rectifier converts the high frequency signal to a corresponding DC level.

8. The circuit of claim 1 further comprising:

a microcontroller unit to integrate the stages of the circuit.

9. The circuit of claim 1 further comprising:

a microcontroller unit programmed to identify the electrical connection between the power supply and the electrical device based upon the output of the rectifier stage.

10. A system for detecting an electrical connection between an electrical device and a power supply wherein a power cable is used to electrically connect a positive power rail and a ground power rail between the electrical device and the power supply wherein the power supply transmits DC power to the electrical device and further wherein the electrical device has capacitance circuitry to remove a high frequency signal transmitted to the electrical device via the positive power rail when the electrical device is electrically connected to the power supply, the system comprising:

a microcontroller unit that generates the high frequency signal; and

a circuit integrated with the microcontroller unit wherein the circuit changes a magnitude of the high frequency signal and modulates the high frequency signal onto the positive power rail between the power supply and the electrical device wherein the circuit removes frequencies other than the high frequency signal from the positive power rail wherein the circuit converts the high frequency signal on the positive power rail to a known DC level and outputs the known DC level to the microcontroller unit wherein the circuit outputs a nominal level to the microcontroller unit when the high frequency signal is removed by the capacitance circuitry of the electrical device wherein the microcontroller unit detects an absence of the electrical connection between the power supply and the electrical device when the output of the circuit is the known DC level wherein the microcontroller unit detects a presence of the electrical connection between the power supply and the electrical device when the output of the circuit is the nominal level.

11. The system of claim 10 further comprising:

a threshold value between the known DC level and the nominal level programmed into the microcontroller unit for detecting the electrical connection between the power supply and the electrical device.

12. The system of claim 10 wherein the circuit amplifies the high frequency signal on the positive power rail before converting the high frequency signal to the known DC level.

13. The system of claim 10 wherein the high frequency signal has a peak-to-peak magnitude that is less than a nominal value of the DC power transmitted from the power supply to the electrical device.

14. The system of claim 10 further comprising:

an alarm initiated by the microcontroller unit following detection of the electrical connection between the power supply and the electrical device.

15. A method for detecting an electrical connection between a power supply and an electrical device with a microcontroller unit by monitoring a positive power rail between the power supply and the electrical device, the method comprising the steps of:

generating a high frequency signal;

modulating the high frequency signal onto the positive power rail;

filtering the high frequency signal on the positive power rail to detect the high frequency signal on the positive power rail; and

rectifying the high frequency signal to convert the high frequency signal to a first DC level.

16. The method of claim 15 further comprising the step of:

amplifying the high frequency signal.

17. The method of claim 15 further comprising the step of:

smoothing the high frequency signal.

18. The method of claim 15 further comprising the step of:

outputting the first DC level which provides an indication that the electrical connection does not exist between the power supply and the electrical device.

19. The method of claim 15 further comprising the step of:

outputting a second DC level if the high frequency signal is removed by the electrical device wherein the second DC level provides an indication of the electrical connection between the power supply and the electrical device.

20. The method of claim 15 further comprising the step of:

initiating an alarm after detecting the first DC level.