Serial bus auto-addressing

A method for controlling a serial data bus system comprising:

• a bus line;
• a bus master connected to the bus line;
• and
• a plurality of bus nodes serially connected to the bus line;
• wherein the plurality of bus nodes includes:
• at least two addressable bus nodes operable to receive addresses in an addressing phase;
• and
• zero or more standard bus nodes having respectively already fixed addresses;
• wherein the method includes the addressing phase for assigning the addresses to at least one of the at least two addressable bus nodes, and an operating phase for operating the data bus system after termination of the addressing phase;
• wherein, in the addressing phase, at least two of the plurality of bus nodes are operative to feed into the bus line a respective current flowing to the bus master, and the plurality of bus nodes includes:
• a first bus node, connected to the bus line at a site upstream from, and closest to the bus master;
• a last bus node, connected to the bus line at a site upstream from, and farthest from the bus master;
• and
• zero or more middle bus nodes, connected to the bus line in between the first bus node and the last bus node;
• wherein:
• each of the at least two addressable bus nodes is operable to receive an address assigned from the bus master during the addressing phase and comprises a current measurement circuit adapted to be switched into the bus line and a controllable bypass switch connected in parallel to the current measurement circuit, and,
• each of the zero or more standard bus nodes has the respective address that is fixed prior to performing the addressing phase,
• wherein, in the method;
• in the addressing phase, an address is assigned to each addressable bus node in an open state of the bypass switch, and
• in the operating phase, the current measurement circuit of each addressed addressable bus node is bypassed by closing the bypass switch.

An addressable bus node for a serial data bus system, the bus system comprising:

• a bus line;
• a bus master connected to the bus line;
• and
• a plurality of bus nodes serially connected to the bus line;
• wherein the plurality of bus nodes includes:
• at least two addressable bus nodes operable to receive addresses assigned by the bus master in an addressing phase;
• and
• zero or more standard bus nodes having respectively an already fixed address:
• the addressable bus node comprising:
• a current measurement circuit adapted to be switched into the bus line;
• a bypass switch connected in parallel to the current measurement circuit;
• an addressing current source for feeding into the bus line an address current flowing into the bus master;
• and
• a control unit for controlling the bypass switch;
• wherein, in an addressing phase of the data bus system for assignment of an address, the control unit is operative to control the bypass switch to assume an open state, and, in an operative phase of the data bus system occurring after termination of the addressing phase, the control unit is operative to control the bypass switch to assume a closed state.