Current-monitoring apparatus
View Patent ↗A local area networking apparatus comprises a power stage for connecting to a network cable for carrying carry power and data. The power stage comprises a main current flow path which includes a switch comprising at least one transistor positioned in the main current flow path and a current monitoring apparatus for monitoring current flow in the main current flow path, and wherein the current monitoring apparatus comprises a sensor which is not placed in series with the main current flow path. The current monitoring apparatus can comprise a current mirroring stage which is arranged to mirror current flowing in the main current flow path to a monitoring current flow path. The switch can be implemented as a set of switches.
1. A power supply apparatus, comprising:
a substrate;
at least one power switch mounted on, or integrated with, the substrate, the power switch comprising:
a first temperature sensor configured to sense a local temperature of the power switch; and
a first controller configured to variably control current through the power switch based on the locally sensed temperature;
a second temperature sensor positioned on the substrate and configured to sense an overall temperature of the substrate; and
a second controller, responsive to the second temperature sensor, configured to control current flow through the power switch and configured, to control DC-DC converter.
2. The power supply apparatus according to claim 1 , wherein the first controller is arranged to regulate the current flow through the power switch responsive to the second temperature sensor.
3. The power supply apparatus according to claim 1 , wherein the second temperature sensor is positioned substantially centrally on the substrate.
4. A Power Sourcing Equipment (PSE) device configured for use in a Power over Ethernet (PoE) system, comprising the power supply apparatus according to claim 1 .
5. A powered device, comprising the power supply apparatus according to claim 1 .
6. The power supply apparatus according to claim 1 , wherein:
the first controller is configured to variably control current through the power switch to be one of at least two non-zero values, wherein the first controller is configured to select the current based on the locally sensed temperature.
7. The power supply apparatus according to claim 6 , wherein the substrate is a semiconductor substrate.
8. The power supply apparatus according to claim 6 , wherein the first temperature sensor further comprises a diode, and is configured to sense the local temperature of the power switch by measuring a voltage drop of the diode when a reference current passes through the diode.
9. A network-attached device comprising the power supply apparatus of claim 6 .
10. A power over Ethernet device comprising the power supply apparatus of claim 6 .
11. The power supply apparatus of claim 6 , wherein the first controller is configured to select the current to be zero based on the locally sensed temperature.
12. The power supply apparatus of claim 6 , wherein the first controller is configured to decrease the current to a non-zero current value when the locally sensed temperature exceeds a temperature threshold.
13. The power supply apparatus of claim 6 , wherein the first controller is configured to:
decrease the current to a first current threshold when the locally sensed temperature exceeds a first temperature threshold; and
decrease the current to a second current threshold when the locally sensed temperature exceeds a second temperature threshold.
14. A switch, comprising:
a first temperature sensor configured to sense a temperature of the switch;
a controller configured to variably control current through the switch based on the temperature of the switch;
a substrate, wherein the temperature sensor and the controller are positioned on the substrate;
a second temperature sensor positioned on the substrate and configured to sense a second temperature; and
a second controller, configured to control current flow through the switch based on the second temperature and is configured to control a DC-DC converter.
15. The switch of claim 14 , wherein the second temperature sensor is positioned substantially centrally on the substrate.
16. The switch of claim 14 , wherein the first controller is configured to control current flow through the switch based on the second temperature.