Circuit device and method of current limit-based disconnect detection
First Claim
1. A power sourcing equipment (PSE) device comprising:
- at least one network port adapted to couple to a powered device to provide power and optionally data to the powered device via a network cable;
a current limiter circuit coupled to the at least one network port and having an adjustable threshold; and
a logic circuit coupled to the current limiter circuit and adapted to;
reduce the adjustable threshold of the current limiter circuit to a threshold level that is below a nominal operating current level by selectively adjusting an effective resistance of a sense resistor coupled between the at least one network port and a power supply;
after a period of time has elapsed during which the current limiter circuit is not activated, the logic circuit is adapted to determine that the powered device is disconnected from the at least one network port.
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Accused Products
Abstract
In a particular embodiment, a power sourcing equipment (PSE) device includes at least one network port adapted to couple to a powered device to provide power and optionally data to the powered device via a network cable. The PSE device further includes a current limiter circuit coupled to the at least one network port and having an adjustable threshold. The PSE device also includes a logic circuit coupled to the current limiter circuit and adapted to reduce the adjustable threshold of the current limiter circuit to have a threshold level that is below a nominal operating current level. After a period of time has elapsed during which the current limiter circuit is not activated, the logic circuit is adapted to determine that the powered device is disconnected from the at least one network port.
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Citations
21 Claims
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1. A power sourcing equipment (PSE) device comprising:
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at least one network port adapted to couple to a powered device to provide power and optionally data to the powered device via a network cable; a current limiter circuit coupled to the at least one network port and having an adjustable threshold; and a logic circuit coupled to the current limiter circuit and adapted to; reduce the adjustable threshold of the current limiter circuit to a threshold level that is below a nominal operating current level by selectively adjusting an effective resistance of a sense resistor coupled between the at least one network port and a power supply; after a period of time has elapsed during which the current limiter circuit is not activated, the logic circuit is adapted to determine that the powered device is disconnected from the at least one network port. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method comprising:
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reducing a current limit threshold of a current limiter circuit to a current level that is below a nominal operating current level of a powered device coupled to an interface port of a power sourcing equipment device, the current limiter circuit adapted to selectively limit a port current at the interface port, wherein the current limit threshold is reduced by altering an effective resistance of a sense resistor coupled between the interface port and a power supply; monitoring the current limiter circuit to determine when the current limiter circuit activated; determining that the powered device is disconnected from the interface port when the current limiter is not activated after a period of time has elapsed; and turning off power to the interface port in response to determining that the powered device is disconnected. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A circuit device comprising:
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at least one network port adapted to couple to a powered device to provide power and optionally data to the powered device via a network cable; a sense resistor coupled between the at least one network port and a power supply; a current limiter circuit coupled to the at least one network port, the current limiter circuit having an adjustable threshold; and a logic circuit coupled to the current limiter circuit and adapted to; change the adjustable threshold to a reduced threshold level that is below a nominal operating threshold by altering an effective resistance of the sense resistor; detect activation of the current limiter circuit to limit a port current to the at least one network port when the powered device is connected to the at least one network port; reset the adjustable threshold to a level that is greater than or equal to the nominal operating threshold when activation of the current limiter circuit is detected. - View Dependent Claims (17, 18, 19, 20, 21)
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Specification