Magnetic isolation of power sourcing equipment control circuitry
AssigneeLinear Technology Corporation
InventorSteven Andrew Robbins
Life of this patent
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Abstract
A circuit for providing electrical isolation of Power Sourcing Equipment (PSE) circuitry from external circuitry in a Power over Ethernet (PoE) system has an inductive circuit for providing an isolation barrier to electrically isolate an isolated side of the isolation circuit from a non-isolated side of the isolation circuit. A signal path circuitry is configured for transferring bidirectional and/or unidirectional signals over the isolation barrier between respective nodes at the isolated and non-isolated sides.
Claims24
In a Power over Ethernet system, an isolation circuit for providing electrical isolation of Power Sourcing Equipment (PSE) circuitry from external circuitry, the isolation circuit comprising:
- a first inductive circuit for providing an isolation barrier to electrically isolate an isolated side of the isolation circuit from a non-isolated side of the isolation circuit,
- a first node configured at the non-isolated side for providing connection to the external circuitry,
- a second node configured at the isolated side for providing connection to the PSE circuitry, and
- signal path circuitry configured for transferring a first signal in a first direction from the first node to the second node, and in a second direction from the second node to the first node;
- the signal path circuitry including:
- a first transfer circuit and a second transfer circuit, the first transfer circuit being configured for transmitting the first signal in the first direction to the second transfer circuit over the isolation barrier, the second transfer circuit being configured for transmitting the first signal in the second direction to the first transfer circuit over the isolation barrier;
- a first arbitration circuit having a first input responsive to the first signal transferred from the first node in the first direction, a second input responsive to the first signal transferred in the second direction, a first output for transferring the first signal to the first transfer circuit in the first direction, and a control output, and
- a first gate circuit controlled by the control output of the first arbitration circuit and having an output for transferring the first signal to the first node in the second direction.
A method for electrically isolating a power supply circuit in a system for providing power over a communication link, the method comprising the steps of:
- providing a magnetic isolation barrier between the power supply circuit and external circuitry,
- transferring a first signal in a first direction from a first circuit node to a second circuit node over the magnetic isolation barrier,
- transferring the first signal in a second direction from the second circuit node to the first circuit node over the magnetic isolation barrier,
- operating a first arbitration circuit responsive to the first signal transferred in the first direction and to the first signal transferred in the second direction, so as to prevent a feedback signal from being supplied to the first node when the first signal is transferred from the first node in the first direction, and
- operating a second arbitration circuit responsive to the first signal transferred in the first direction and to the first signal transferred in the second direction, so as to prevent a feedback signal from being supplied to the second node when the first signal is transferred from the second node in the second direction.
A system for providing power over a communication link having a power supply circuit and an isolation circuit for electrically isolating the power supply circuit from external circuitry, the isolation circuit comprising:
- an inductive circuit for providing an isolation barrier to electrically isolate an isolated side of the isolation circuit from a non-isolated side of the isolation circuit,
- first, second and third nodes configured at the non-isolated side for providing connection to the external circuitry,
- fourth, fifth and sixth nodes configured at the isolated side for providing connection to the power supply circuit, and
- signal path circuitry configured for transferring a first signal in a first direction from the first node to the fourth node, and in a second direction from the fourth node to the first node, for transferring a second signal in the second direction from the fifth node to the second node, and for transferring a third signal in the first direction from the third node to the sixth node,
- the signal path circuitry including:
- a first transfer circuit and a second transfer circuit,
- the first transfer circuit being configured for time multiplexing the third signal and the first signal transferred in the first direction and producing a first output signal transmitted over the isolation barrier to the second transfer circuit,
- the second transfer circuit being configured for time multiplexing the second signal and the first signal transferred in the second direction and producing a second output signal transmitted over the isolation barrier to the first transfer circuit.
Dependencies are inferred from the claim text.