Circuits and methods for detecting the presence of a powered device in a powered network
First Claim
Patent Images
1. A circuit for detecting the presence of a powered device in a powered network connection, the circuit comprising:
- an oscillator for providing a time-varying voltage signal; and
an analog amplifier circuit for receiving the time-varying voltage signal from the oscillator as an input, applying the time-varying voltage signal to the powered network connection, and sensing the current flowing through a coupling capacitor required to drive a load connected to the analog amplifier circuit,wherein the analog amplifier circuit comprises a dual-output trans-conductance amplifier, the dual-output trans-conductance amplifier comprising;
an inverting input;
a non-inverting input;
a bias current input;
a primary output; and
a secondary output.
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Abstract
Circuits and methods for detecting the presence of a powered device in a powered network connection and removing power from the powered network connection when no powered device is present are disclosed. The circuits and methods involve applying a time-varying voltage signal into an analog amplifier circuit that converts the voltage into a current indicative of the impedance of the connection. The analog amplifier circuit may be implemented with a dual-output trans-conductance amplifier that provides a digital voltage to indicate the removal of the powered device from the powered network connection.
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Citations
38 Claims
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1. A circuit for detecting the presence of a powered device in a powered network connection, the circuit comprising:
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an oscillator for providing a time-varying voltage signal; and an analog amplifier circuit for receiving the time-varying voltage signal from the oscillator as an input, applying the time-varying voltage signal to the powered network connection, and sensing the current flowing through a coupling capacitor required to drive a load connected to the analog amplifier circuit, wherein the analog amplifier circuit comprises a dual-output trans-conductance amplifier, the dual-output trans-conductance amplifier comprising; an inverting input; a non-inverting input; a bias current input; a primary output; and a secondary output. - View Dependent Claims (2, 3, 4, 7, 9, 10)
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5. A circuit for detecting the presence of a powered device in a powered network connection, the circuit comprising:
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an oscillator for providing a time-varying voltage signal; and an analog amplifier circuit for receiving the time-varying voltage signal from the oscillator as an input, applying the time-varying voltage signal to the powered network connection, and sensing the current flowing through a coupling capacitor required to drive a load connected to the analog amplifier circuit, wherein the time-varying voltage signal from the oscillator is applied at the inverting input of the analog amplifier circuit.
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6. A circuit for detecting the presence of a powered device in a powered network connection, the circuit comprising:
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an oscillator for providing a time-varying voltage signal; and an analog amplifier circuit for receiving the time-varying voltage signal from the oscillator as an input, applying the time-varying voltage signal to the powered network connection, and sensing the current flowing through a coupling capacitor required to drive a load connected to the analog amplifier circuit, wherein the time-varying voltage signal from the oscillator is applied at the non-inverting input of the analog amplifier circuit in a non-inverting analog amplifier configuration.
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8. A circuit for detecting the presence of a powered device in a powered network connection, the circuit comprising:
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an oscillator for providing a time-varying voltage signal; an analog amplifier circuit for receiving the time-varying voltage signal from the oscillator as an input, applying the time-varying voltage signal to the powered network connection, and sensing the current flowing through a coupling capacitor required to drive a load connected to the analog amplifier circuit; a first feedback resistor connected between the primary output and the inverting input; and a second feedback resistor connected between the oscillator and the inverting input.
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11. A circuit for detecting the presence of a powered device in a powered network connection, the circuit comprising:
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an oscillator for providing a time-varying voltage signal; and an analog amplifier circuit for receiving the time-varying voltage signal from the oscillator as an input, applying the time-varying voltage signal to the powered network connection, and sensing the current flowing though a coupling capacitor required to drive a load connected to the analog amplifier circuit, wherein the circuit is a component within a power sourcing equipment in the powered network connection. - View Dependent Claims (12, 13)
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14. A circuit for detecting the presence of a powered device in a powered network connection, the circuit comprising:
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an oscillator for providing a time-varying voltage signal; and an analog amplifier circuit for receiving the time-varying voltage signal from the oscillator as an input, applying the time-varying voltage signal to the powered network connection, and sensing the current flowing through a coupling capacitor required to drive a load connected to the analog amplifier circuit, wherein the load comprises a coupling capacitor connected to the powered device in the powered network connection. - View Dependent Claims (15)
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16. A power sourcing equipment for providing power to a powered network connection, the power sourcing equipment comprising:
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an AC disconnect circuit for detecting the presence of a powered device in a powered network connection, the AC disconnect circuit comprising; an oscillator for providing a time-varying voltage signal; and an analog amplifier circuit for receiving the time-varying voltage signal from the oscillator as an input, applying the time-varying voltage signal to the powered network connection, and sensing the current flowing through a coupling capacitor required to drive a load connected to the analog amplifier circuit. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method for detecting the presence of a powered device in a powered network connection and removing power from the powered network connection when the powered device is disconnected from the powered network connection, the method comprising:
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detecting a valid powered device signature in the powered network connection; supplying power to the powered network connection if a valid powered device signature is detected; applying a time-varying voltage signal into the powered network connection; converting the time-varying voltage signal into a current with an analog amplifier circuit; and measuring the impedance of the powered network connection by sensing the current flowing through a coupling capacitor connected to the analog amplifier circuit. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38)
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Specification