Remote current sensing and communication over single pair of power feed wires
First Claim
1. A host device couplable to a remote device via a single wire pair, said single wire pair comprising a first wire and a second wire, said remote device comprising first remote signal generation circuitry operable to generate a first remote signal and a first remote current modulator operable to modulate a current component of a power signal present on said single wire pair with said first remote signal when said first remote signal is communicated to said host device, said host device comprising:
- a voltage reference and control loop circuit which generates and enforces a substantially constant voltage component of said power signal present on said single wire pair during communication between said first remote signal to said host device and said host device to said first remote device; and
a first host current de-modulator operable to de-modulate said first remote signal from said current component of said power signal present on said single wire pair during communication of said first remote signal to said host device.
1 Assignment
0 Petitions
Accused Products
Abstract
Disclosed is a novel technique for transferring power and signals between two electrical devices over a single wire pair. In particular, a remote sensor is connected to a host device. Power to the remote sensor is supplied through a voltage reference and control loop circuit that holds the voltage component of the power signal present on the wire pair constant during remote current sensing. The remote sensor itself can transmit measurements or information by driving a load on the sensor and thereby modulating the loop current. The current signal in the sensor-to-host loop can be a precision AC analog signal or a serial digital bit stream. Both types of signals can coexist using a multiplexing scheme.
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Citations
31 Claims
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1. A host device couplable to a remote device via a single wire pair, said single wire pair comprising a first wire and a second wire, said remote device comprising first remote signal generation circuitry operable to generate a first remote signal and a first remote current modulator operable to modulate a current component of a power signal present on said single wire pair with said first remote signal when said first remote signal is communicated to said host device, said host device comprising:
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a voltage reference and control loop circuit which generates and enforces a substantially constant voltage component of said power signal present on said single wire pair during communication between said first remote signal to said host device and said host device to said first remote device; and a first host current de-modulator operable to de-modulate said first remote signal from said current component of said power signal present on said single wire pair during communication of said first remote signal to said host device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A host device couplable to a remote device via a single wire pair, said single wire pair comprising a first wire and a second wire, said remote device comprising first remote signal generation circuitry operable to generate a first remote signal and a first remote current de-modulator operable to de-modulate a host signal from a current component of a power signal present on said single wire pair when said host signal is communicated to said remote device, said host device comprising:
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a voltage reference and control loop circuit which enforces a substantially constant voltage component of said power signal present on said single wire pair during communication between of said first remote signal to said host device and said host device to said first remote device; and host signal generation circuitry operable to generate said host signal; a host current modulator operable to modulate said current component of said power signal present on said single wire pair with said host signal while said voltage reference and control loop circuit enforces a substantially constant voltage component of said power signal present on said single wire pair during communication of said host signal to said remote device. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
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22. A method for channeling signals between a host device and a remote device, said host device and said remote device connected by a single wire pair comprising a first wire and a second wire, and said host device supplying a power signal comprising a current component and a voltage component to said remote device over said single wire pair, said method comprising:
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at said host device, holding said voltage component of said power signal present on said wire pair substantially constant during communication between to said host device and said remote device; at said remote device, generating a remote signal; at said remote device, current-modulating said remote signal with said current component of said power signal present on said wire pair; and
at said host device, de-modulating said current component of said power signal present on the wire pair to recover said remote signal. - View Dependent Claims (23, 24, 25, 26, 27)
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28. A method for channeling signals between a host device and a remote device, said host device and said remote device connected by a single wire pair comprising a first wire and a second wire, and said host device supplying a power signal comprising a current component and a voltage component to said remote device over said single wire pair, said method comprising:
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at said host device; holding said voltage component of said power signal present on said wire pair substantially constant during communication between said host device and said remote device; generating a host signal; and current-modulating said host signal with said current component of said power signal present on said wire pair; and at said remote device; de-modulating said current component of said power signal present on the wire pair to recover said host signal. - View Dependent Claims (29, 30)
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31. A voltage reference and power loop control circuit for supplying power and channeling signals from a remote device over a single wire pair, said single wire pair comprising a first wire and a second wire, said remote device operable to modulate a current component of a power signal present on said single wire pair with a remote signal, said circuit comprising:
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a voltage generator which generates a reference voltage that enforces a substantially constant voltage present on said single wire pair during communication between said host device and said remote device; an operational amplifier having a first input terminal coupled to receive said reference voltage, a second input terminal coupled to said first wire, a feedback resistor coupled between said output terminal and said second input terminal, and an output terminal which outputs an operational amplifier output voltage signal that reflects a current that is passing through said feedback resistor, wherein said operational amplifier operates to mirror said reference voltage received at said first input terminal on said second input terminal; and a filter which filters said operational amplifier output voltage signal to recover said remote signal.
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Specification