BUS-CAPABLE DEVICE ARRANGEMENT HAVING A SWITCHABLE TERMINATING RESISTOR

Abstract

The invention relates to a bus-capable device having an input interface and an output interface for connecting to a serial bus, particularly a CAN bus, wherein the input interface and the output interface each have at least one signal line connection, and further having a terminating resistor for terminating the bus and a switch apparatus for switching the terminating resistor active as a function of the connection status of the input and output interfaces, wherein the input interface and the output interface each having a supply voltage connection for providing a supply voltage to the output and/or input interfaces of a respective next bus-capable device and a feedback connection for receiving the supply voltage from an output and/or input interface of a respective next bus-capable device, wherein the switch apparatus has an evaluation circuit for determining the presence of the supply voltage at the feedback connections of the input and output interfaces and an activation circuit for switching the terminating resistor active when the supply voltage is found by the evaluation circuit to be absent from the feedback connection of the input interface and/or from the feedback connection of the output interface.

Claims

1. A bus-capable device comprising: an input interface and an output interface for connection to a serial bus, wherein the serial bus comprises a CAN bus, and wherein the input interface and the output interface each have at least one signal line connection; a terminating resistor for terminating the bus; a switching device for switching the terminating resistor being active in dependence on the connection state of the input and output interfaces, wherein the input interface and the output interface each comprise a supply voltage connection for providing a supply voltage to the output and/or input interfaces of a respective next bus-capable device and comprise a feedback connection for receiving the supply voltage from an output and/or input interface of a respective next bus-capable device, and wherein the switching device comprises an evaluation circuit for determining the application of the supply voltage to the feedback connections of the input and output interfaces and an activation circuit for activating the terminating resistor when the lack of the supply voltage is determined by the evaluation circuit at the feedback connection of the input interface and/or at the feedback connection of the output interface.

2. The device of claim 1, wherein the supply voltage connection and/or the feedback connection of the input interface and/or of the output interface is/are galvanically separate and/or is/are electrically insulated from the signal line connection.

3. The device of claim 1, wherein the input interface and the output interface each comprise two signal line connections.

4. The device of claim 1, wherein the input interface and the output interface each comprise a ground connection, and wherein the ground connections each comprise a galvanically separate ground.

5. The device of claim 1, wherein the input interface and/or the output interface each has/have a five-pole plug connector, and wherein the five-pole plug connectors each are in the form of a five-pole M12 plug connector.

6. The device of claim 1, wherein the supply and feedback connections are arranged at the input and output interfaces such that the supply connection of the input interface is connected to the feedback connection of the output interface of a next device to be connected to the bus, and wherein the feedback connection of the input interface is connected to the supply connection of the output interface of the next device to be connected to the bus, and wherein the supply connection of the output interface is connected to the feedback connection of the input interface of the next device to be connected to the bus, and wherein the feedback connection of the output interface is connected to the supply connection of an input interface of the next device to be connected to the bus.

7. The device of claim 1, wherein the evaluation circuit comprises two switching elements connected in series of which a first of the two switching elements is connected to the feedback connection of the input interface and a second of the two switching elements is connected to the feedback connection of the output interface.

8. The device of claim 7, wherein the two switching elements are configured to draw a supply voltage connection of the activation circuit to ground when both switching elements are switched through or block from ground when at least one of the switching elements is not switched through.

9. The device of claim 1, wherein the evaluation circuit comprises two switching elements each comprising a field effect transistor, wherein the field effect transistors are each in the form of a MOSFET, and wherein the field effect transistors are each configured to receive the supply voltage applied to the respective feedback connection or a voltage signal derived therefrom as an input signal.

10. The device of claim 9, wherein the two switching elements are configured to draw a supply voltage connection of the activation circuit to ground when both switching elements are switched through or block from ground when at least one of the switching elements is not switched through.

11. The device of claim 1, wherein the evaluation circuit comprises two switching elements, and wherein the activating circuit has a relay that is connected at the input side to the connection path between a supply voltage connection and the two switching elements connected in series.

12. The device in of claim 1, wherein the evaluation circuit comprises two switching elements, and wherein the relay is configured as an optical relay that has an input resistor that is connected to the connection path between the supply voltage connection and the two switching elements connected in series.

13. The device of claim 1, wherein the activation circuit is connected at the output side to the terminating resistor that is connectable via the activation circuit to the two signal line connections of the input and output interfaces.

14. A device arrangement comprising a plurality of bus-capable devices that are each configured in accordance with claim 1.

15. The device arrangement of claim 14, wherein a first one of the plurality of bus-capable devices is connected at its output interface to the input interface of a second bus-capable device whose output interface is in turn connected to the input interface of a third device, with the input and output interfaces being connected to one another.

16. The device arrangement of claim 14, wherein the plurality of bus-capable devices each form an energy storage cell and/or are integrated in an energy storage cell.

17. The device arrangement of claim 16, wherein the energy storage cell has at least one storage block comprising a capacitor store, a power controller, and a control device that is connected to the storage block and/or to the power controller, and wherein the capacitor store comprises a double layer capacitor, and wherein the power controller comprises a bidirectional DC-DC controller, wherein the control device is connected to the bus via a respective input interface and output interface.

18. An energy storage device comprising a plurality of energy storage cells that respectively have at least one storage block comprising a capacitor store and a power control comprising a bipolar DC-DC power control, wherein each storage cell comprises a control device for controlling the storage block and/or the DC-DC power control, and wherein the control devices each comprise a respective input interface and an output interface for connection to a serial bus, wherein each energy storage cell is configured as a bus-capable device in accordance with claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention will be explained in more detail in the following with reference to a preferred embodiment and to associated drawings. There are shown in the drawings:

[0037] FIG. 1: a bus-capable device having a bus input interface and a bus output interface as well as a switching device for switching on and off a terminating resistor for terminating the bus connectable to the input and output interfaces; and

[0038] FIG. 2: the interconnection of a plurality of bus-capable devices that are each provided with a switching device for the automatic switching on and off of a terminating resistor.

DETAILED DESCRIPTION

[0039] As FIG. 1 shows, a bus-capable device—just like the further bus-capable devices 2 and 3 in FIG. 2—can have an input interface 5 and an output interface 6 respectively that can be formed, for example, in the form of plugs and that can be separately plugged into connected to a serial bus 16, in particular to a CAN bus.

[0040] Each of the input and output interfaces 5 and 6 here comprises two respective signal line connections 7 and 8 to be connected to the two signal lines of a serial bus 16, in particular in the form of a CAN bus, at its CAN high and CAN low lines.

[0041] In addition to the two signal line connections 7 and 8, each of the input and output interfaces 5 and 6 further comprise a supply voltage connection 9 to provide a supply voltage to the interface of the respective next device and comprise a feedback connection 10 with whose aid the supply voltage provided by a next device can be tapped or received. Said supply and feedback connections 9 and 10 are here advantageously each galvanically separate and/or electrically insulated from the signal line connections 7 and 8.

[0042] In addition to said supply and feedback connections 9 and 10, each of the input and output interfaces 5 and 6 advantageously further comprise a ground connection 22 that is likewise advantageously galvanically separate or is electrically insulated from the other connections.

[0043] As FIGS. 1 and 2 show, the supply connections 9 and feedback connections 10 are arranged complementary to one another at the input interface 5 and at the output interface 6 such that the supply voltage connection 9 of the input interface 5 is connected to the feedback connection 10 of an output interface 6 of the next device while the feedback connection 10 of the input interface 5 is connected to the supply connection 9 of the output interface of the next connected device. In other words, the arrangement of the supply and feedback connections 9 and 10 is made such that the feedback connection of the input interface receives the supply voltage from the output interface of a next device and the feedback connection of the output interface obtains the supply voltage from the input interface of a next device, cf. FIG. 2.

[0044] The signal line connections 7 and 8 and the ground connection 11 are, however, arranged in the same manner so that every interface is equally connected to the ground and the CAN high connection is connected to the CAN high line and the CAN low connection to the CAN low line.

[0045] As FIG. 1 and also FIG. 2 illustrate, the signals received at the feedback connections 10 of the input interface 5 and of the output interface 6 in the form of the possibly received supply voltage are provided to an evaluation circuit 14 that comprises two switching elements 17, preferably in the form of field effect transistors, that are connected in series. Said switching elements 17 can in particular be so-called MOSFETs.

[0046] As FIG. 1 shows, the supply voltages received at the feedback connections 10 can be provided to said MOSFETs 17 over a series resistor as an input signal or as a switching signal, with the one switching element 17 being connected to the feedback connection 10 of the input interface 5, while the other switching element 17 of the two elements connected in series is connected to the feedback connection 10 of the output interface 6.

[0047] The field effect transistor stage comprising the two MOSFETs 17 is connected to ground, cf. the ground connection 11-17, on the one hand, while the other end of the switching elements 17 connected in series is connected to the supply voltage.

[0048] If the two field effect transistors 17 are switched through, which is the case on application of the supply voltage to both feedback connections 10 of the two input and output interfaces 5 and 6, the supply voltage is drawn to ground. If, however, one of the two switching elements 17 or if both switching elements remains/remain blocked, the supply voltage is not drawn to ground and accordingly drives a switching relay 18 into a different switched position.

[0049] Said relay 18 is part of an activation circuit 15 by means of which a terminating resistor 12 provided at the device can be activated and deactivated. Said relay 18 can here in particular be an optical relay and can have a series resistor or a plurality of series resistors at the input side, cf. FIG. 1.

[0050] Depending on whether the supply voltage is drawn to ground via the switching elements 17 or is not drawn to ground, said relay 18 switches the terminating resistor 12 connected at the output side to the two signal line connections 7 and 8.

[0051] At the input side, the relay 18 is connected to the connection path between the supply voltage and ground, and indeed advantageously between the supply voltage connection and the two switching elements 17 connected in series, cf. FIG. 1.

[0052] As FIG. 2 shows, a plurality of such bus-capable devices 1, 2, and 3 can be serially connected to the bus 16, but with only the middle device 2 being connected to the bus 16 both at its input interface 5 and at its output interface 6. The input interface 5 at the first device 1 remains unconnected and only the output interface 6 is connected to the bus 16. The input interface 5 is connected at the last or third device 3, while the output interface 6 remains unconnected.

[0053] The input interface 5 of the first device 1 accordingly does not receive the supply voltage at its feedback connection 10—due to a lack of connection of a further device—so that the MOSFET 17 connected to the feedback connection 10 of the input interface 5 is not switched through and the supply voltage is accordingly not drawn to ground. The relay 18 is hereby switched into the active position in which the terminating resistor 12 is switched on.

[0054] In an analog manner, the output interface 6 of the third or last device 3 lacks a supply voltage incoming at the feedback connection 10 so that the MOSFET 17 connected to the output interface 6 or to its feedback connection 10 remains blocked and the supply voltage is likewise not drawn to ground. The supply voltage hereby also remains switched to the relay 18 at the third device 3, which relay 18 correspondingly activates the terminating resistor 12 of the third device 3.

[0055] In the second device 2, however, the supply voltage is applied both to the feedback connection 10 of the input interface 5 and to the feedback connection 10 of the output interface 6 so that both MOSFETs 17 switch through and draw the supply voltage to ground. The terminating resistor 12 accordingly remains deactivated.

[0056] The bus-capable devices 1, 2, and 3 shown in FIG. 2 can in particular be energy storage cells that each comprise a storage block, a capacitor store, in particular a double layer capacitor, and can comprise a bidirectional DC-DC controller. Such energy storage cells can furthermore each have a local or internal control device that controls the storage blocks and the DC-DC controllers and that is connected to the bus 16 via said input and output interfaces 5 and 6.

[0057] Provision can here advantageously be made that the switching device 13, including the evaluation circuit 14 and the activation circuit 15, and the terminating resistor 12 are integrated in the respective energy storage cell, that is in the respective device 1, 2, or 3, is in particular accommodated in the interior of the housing of the energy storage cell.