Bus power-supply device and node
AssigneeNEC Corporation
InventorMasahisa Kobayashi
Life of this patent
Estimating the term…
Abstract
A bus power-supply device structured to supply power from a power-supply voltage of a node to a serial bus connected to the node through a physical layer and a plurality of connectors conductive to each other of the node, which device, when none of a power-supply voltage of the node is supplied, supplies a DC voltage from the serial bus to the physical layer and when the power-supply voltage is supplied, cuts off a path for supplying a DC voltage from the serial bus to the physical layer to supply a DC voltage from the power-supply voltage to the physical layer.
Claims13
A bus power-supply device in a node for connection to a serial bus, said bus power-supply device structured to supply power from a power-supply voltage of a node of a proceeding stage to a node of a next stage through the serial bus connected to said node by a physical layer and a plurality of connectors conductive to each other of the node, comprising:
- a power-supply circuit which converts said power-supply voltage into a DC voltage for said serial bus and outputs said DC voltage;
- a converter which converts a DC voltage output from said power-supply circuit into a DC voltage for said physical layer;
- a voltage detection unit which detects said power-supply voltage being supplied or not being supplied to said power-supply circuit;
- a first means connected between said power-supply circuit and said converter for supplying a DC voltage outputted from said power-supply circuit to the serial bus, and for preventing application to said power-supply circuit of a DC voltage from the serial bus;
- a second means connected between said converter and the serial bus for supplying a DC voltage outputted from said power-supply circuit to the serial bus, and for preventing application to said converter and said power-supply circuit of a DC voltage from said serial bus;
- and
- a switch which is connected in parallel with said second means and controlled by an output signal outputted from said voltage detection unit;
- wherein when an output voltage of said power-supply circuit is detected, said switch is turned off, and when an output voltage of said power-supply circuit is not detected, said switch is turned on.
A node having a bus power-supply device structured to supply power from a power-supply voltage to a node of a next stage through a serial bus connected to said node by a physical layer and a plurality of connectors conductive to each other of the node, comprising:
- a plurality of connectors each having a power-supply terminal to which a DC voltage is applied from other nodes through said serial bus and a signal terminal to and from which a signal from other nodes is in input and output;
- a physical layer which outputs a signal input through a signal terminal of one connector to a signal terminal of the other connector, wherein
- power-supply terminals of said plurality of connectors are rendered conductive to each other,
- said bus power-supply device comprises
- a power-supply circuit which converts said power-supply voltage into a DC voltage for said serial bus and outputs said DC voltage;
- a converter which converts a DC voltage output from said power-supply circuit into a DC voltage for said physical layer;
- a voltage detection unit which detects said power-supply voltage being supplied or not being supplied to said power-supply circuit;
- a first means connected between said power-supply circuit and said converter for supplying a DC voltage outputted from said power-supply circuit to the serial bus, and for preventing application to said power-supply circuit of a DC voltage from the serial bus;
- a second means connected between said converter and the serial bus for supplying a DC voltage outputted from said power-supply circuit to the serial bus, and for preventing application to said converter and said power-supply circuit of a DC voltage from the serial bus;
- and
- a switch which is connected in parallel with said second means and controlled by an output signal outputted from said voltage detection unit;
- wherein when an output voltage of said power-supply circuit is detected, said switch is turned off, and when an output voltage of said power-supply circuit is not detected, said switch is turned on.
Dependencies are inferred from the claim text.