Koninklijke Philips Corporation N.V.

Nxp B.v.

Harm Gerwin Joan Voss

Hendrik Boezen

Stefan Gerhard Erich Butselaar

Patrick Willem Hubert Heuts

The communication bus system comprises a plurality of node circuits (-) and a relay circuit () coupling the node circuits (-). The relay circuit () has a transceiver circuit () for relaying messages () between the node circuits (-) in a normal mode. The transceiver circuit () is powered down in a sleep mode. A detector circuit () detects an incoming message () when the relay circuit () is in a sleep mode. A mode control circuit () powers up the transceiver () in response to detection of an incoming message (). Steps are taken that ensure, in the normal mode, that messages () will not be relayed in unreadable form. The mode control circuit () is arranged to cause the transceiver () to relay a remainder () of the incoming message () after power up. In an embodiment the power needed to transmit the remainder () of the message () is drained from a capacitor () in the power supply () before the power supply () controls the power supply voltage in the normal mode. In another embodiment the detector circuit () temporarily controls the direction of operation of the transceivers () at the start of the normal mode instead of further detectors (-) that normally control the direction of operation in the normal mode.

Communication bus system operable in a sleep mode and a normal mode

In a network a star node (SN) interconnects a plurality of stations (ST&#x2013;ST). The star node (SN) has interfaces (I&#x2013;I), each having a connection terminal (BP) for connecting a selected one of the stations to the star node (SN) and each interface receives at a connection terminal (BP) a signal from the station associated with that interface and forwards the received signal to the connection terminal (BP) of the other interfaces. The star node (SN) further has a common terminal (RT) and each interface has a receiver (CMP) coupled to the connection terminal (BP) for receiving the signal from the associated station, a transmitter (TR) coupled to the connection terminal (BP), a first activity detector (A) for generating a first activity signal (AS) in response to signal transitions at an input (CIP) of the receiver (CMP), a second activity detector (A) for generating a second activity signal (AS) in response to signal transitions at the common terminal (RT), a first switch (SW) for disabling signal transfer from the receiver (CMP) to the common terminal (RT) in response to the second activity signal (AS), and a second switch (SW) for disabling signal transfer from the common terminal (RT) to the transmitter (TR) in response to the first activity signal (AS). The structure of the interface allows easy expansion of the number of interfaces within the star node (SN) and a data protocol without a preamble.

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Nijmegen, Netherlands

Harm Gerwin Joan Voss