Combination of high-side and low-side current sensing in system for providing power over communication link
View Patent ↗A system for supplying power to a load over a communication link has high-side current sensing circuitry for measuring a high-side current value, low-side current sensing circuitry for measuring a low-side current value, and control circuitry responsive to both the high-side current value and the low-side current value to detect a fault condition, detect information from the load, and/or transmit information to the load by creating a prescribed unbalance between the high-side current and the low-side current.
1. A system for supplying power over a communication link, comprising:
high-side current sensing circuitry for measuring a high-side current value,
low-side current sensing circuitry for measuring a low-side current value, and
control circuitry responsive to a combination of the high-side current value and the low-side current value for detecting a fault condition in response to the high-side current value and the low-side current value.
2. The system of claim 1 , wherein the power is supplied over Ethernet.
3. The system of claim 1 , wherein the control circuitry is configured to detect the fault condition in response to a difference between the high-side current value and the low-side current value.
4. The system of claim 1 , wherein the high-side current sensing circuitry comprises an impedance connected between a load and a more positive power supply lead of a pair of power supply leads.
5. The system of claim 1 , wherein the low-side current sensing circuitry comprises an impedance connected between a load and a more negative power supply lead of a pair of power supply leads.
6. The system of claim 1 , wherein the high-side current sensing circuitry and the low-side current sensing circuitry provide DC current sensing.
7. The system of claim 3 , wherein the fault condition is detected when the difference between the high-side current value and the low-side current value exceeds a predetermined value.
8. The system of claim 1 , wherein the power supplied over the communication link is removed when the fault condition is detected.
9. The system of claim 1 , wherein the control circuitry is configured for providing an indication to a user when the fault condition is detected.
10. A system for supplying power to a load via a communication link, comprising:
high-side current sensing circuitry for measuring a high-side current value,
low-side current sensing circuitry for measuring a low-side current value, and
control circuitry responsive to a combination of the high-side current value and the low-side current value for detecting information from the load.
11. The system of claim 10 , wherein the control circuitry is configured for detecting an unbalance between the high-side current value and the low-side current value.
12. The system of claim 10 , wherein the control circuitry is configured for detecting a type of the load based on the high-side current value and the low-side current value.
13. The system of claim 10 , wherein the control circuitry is configured for detecting whether the load has an earth ground connection based on the high-side current value and the low-side current value.
14. The system of claim 10 , wherein the power supply device is configured for transmitting information to the load by providing unbalance between the high-side current value and the low-side current value.
15. A system for supplying power to a load via a communication link, comprising:
high-side current circuitry for providing a path to the load for a high-side current,
low-side current circuitry for providing a path to the load for a low-side current value, and
control circuitry for providing a prescribed unbalance between the high-side current and the low-side current.
16. The system of claim 15 , wherein the prescribed unbalance is provided to present information to the load.
17. In a system for supplying power over a communication link to a load, a method comprising the steps of:
sensing high-side current in high-side circuitry associated with a power supply device,
sensing low-side current in low-side circuitry associated with the power supply device, and
comparing the high-side current and the low-side current to detect a fault condition.
18. The method of claim 17 , further comprising the step of detecting information from the load based on an unbalance between the high-side current and the low-side current.
19. The method of claim 17 , further comprising the step of providing unbalance between the high-side current and the low-side current to transmit information between the power supply device and the load.
20. A local area network comprising:
at least a pair of network nodes,
a network hub, and
communication cabling for connecting the network nodes to the network hub to provide data communications,
the network hub having a power supply device for providing power to a load over the communication cabling, the power supply device including high-side current sensing circuitry for measuring a high-side current value, low-side current sensing circuitry for measuring a low-side current value, and a fault detecting circuit for detecting a fault if a difference between the high-side current value and the low-side current value exceeds a predetermined value.
21. The local area network of claim 20 , wherein the power supply device is configured for providing unbalance between the high-side current value and the low-side current value to transmit information between the power supply device and the load.
22. The local area network of claim 20 , wherein the power supply device is configured to determine information from the load based on a difference between the high-side current value and the low-side current value.