Current-monitoring apparatus
First Claim
1. A power supply apparatus for connecting to a cable which carries power and data, the power supply apparatus comprising:
- 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 configured to monitor current flow in the main current flow path, wherein the current monitoring apparatus comprises a current mirroring stage configured to mirror current flowing in the main current flow path to a monitoring current flow path, wherein the current mirroring stage comprises;
a mirror transistor positioned in the monitoring current flow path; and
a voltage setting stage configured to set voltages at each side of the mirror transistor equal to a corresponding voltage at a respective side of the switch, or to set voltages between terminals of the mirror transistor equal to voltages across corresponding terminals of the switch.
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Accused Products
Abstract
A local area networking apparatus comprises a power stage for connecting to a network cable for carrying 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.
15 Citations
18 Claims
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1. A power supply apparatus for connecting to a cable which carries power and data, the power supply apparatus comprising:
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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 configured to monitor current flow in the main current flow path, wherein the current monitoring apparatus comprises a current mirroring stage configured to mirror current flowing in the main current flow path to a monitoring current flow path, wherein the current mirroring stage comprises; a mirror transistor positioned in the monitoring current flow path; and a voltage setting stage configured to set voltages at each side of the mirror transistor equal to a corresponding voltage at a respective side of the switch, or to set voltages between terminals of the mirror transistor equal to voltages across corresponding terminals of the switch. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A power supply apparatus for connecting to cable, which carries power and data, the power supply apparatus comprising:
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a main current flow path which includes a switch positioned in the main current flow path; and a current monitoring apparatus configured to monitor current flow in the main current flow path, wherein the current monitoring apparatus includes a current mirror configured to mirror current flowing in the main current flow path to a monitoring current flow path, wherein current mirror comprises; a mirror transistor positioned in the monitoring current flow path; and a voltage setting stage configured to set voltages at each side of the mirror transistor equal to a corresponding voltage at a respective side of the switch, or to set voltages between terminals of the mirror transistor equal to voltages across corresponding terminals of the switch.
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Specification