DE102013217398A1 - Electronic multi-channel switching device - Google Patents

Abstract

The invention relates to a multi-channel electronic switching device having one or more parallel input signal lines (1, 2, 3) and one or more output signal lines (17, 18, 19), each input signal line (1, 2, 3) being a bipolar input transistor (4, 5, 6), each of the input signal lines (1, 2, 3) being connected to the base terminal (59, 60, 61) of each one input transistor (4, 5, 6), the emitter terminals (7, 8, 9 ) of the input transistors (4, 5, 6) are connected to a common ground potential terminal (43), wherein the collector terminals (10, 11, 12) of the input transistors (4, 5, 6) are connected to a common main signal conductor (13) and wherein each input transistor (4, 5, 6) can be converted from a signal blocking state to a signal conducting state via an input switching signal line (1, 2, 3), each output signal line (17, 18, 19) being an output transistor (20, 21, 22 ), the emitter terminals (24, 25, 26) of the output transistors (20, 21, 22) being connected to the common main signal conductor (13), the output signal lines (17, 18, 19) being connected to a collector terminal (27, 28 , 29) of an output transistor (20, 21, 22) are connected, wherein the base terminals (62, 63, 64) of the output transistors (20, 21, 22) are each connected to a common ground terminal (33) and wherein each of the collector terminals ( 27, 28, 29) of the output transistors (20, 21, 22) each having an output switching signal line (30, 31, 32) is connected, which is acted upon by an output switching signal. The described circuit combines a low system noise figure with a simple structure and ease of gain control.

Description

The invention relates to a multi-channel electronic switching device in a motor vehicle.

When processing signals of digital or analog form and directing them to specific physical addresses in a motor vehicle, the problem frequently arises that different signal paths use and share the same physical signal path and that this sharing is done by so-called multiplexers or multichannel electronic switching devices independent signals are used. Such switching devices are basically known and allow the switching of one or more input channels to one or more output channels. Usually, in addition, a low-noise amplification of the signals is required in particular for analog signals. In addition, a device for adjusting the gain is often necessary. Usually, such functions are realized in separate components or modules, which on the one hand increases the price and on the other hand degrades the physical quality of the signals due to the processing. A deterioration of the signals is particularly in the automotive sector, there especially in safety-critical applications such as driver assistance systems as possible to avoid at the same time low costs.

Against the background of the prior art, the present invention has the object to provide a multi-channel electronic switching device for a motor vehicle, which avoids the disadvantages mentioned and allows for low signal attenuation and the lowest possible system noise a structurally simple as possible realization.

The object is achieved with the features of the invention according to claim 1. The dependent claims 2 to 10 relate to advantageous embodiments of the invention.

According to the invention there is thus provided a multichannel electronic switching device having either a plurality of parallel input signal lines and one or more output signal lines or one or more input signal lines, wherein each input signal line having a plurality of input signal lines comprises a bipolar input transistor each having a base terminal, a collector terminal and an emitter terminal wherein each of the input signal lines is connected to the base terminal of each one of the input transistors, the emitter terminals of the input transistors being connected to a common ground potential terminal, the collector terminals of the input transistors being connected to a common main signal conductor, and each input transistor being connected via an input switching signal line via an input switching signal a signal blocking state in a signal conducting state, wherein in the presence of at least two output signal lines of each output signal line is associated with a bipolar output transistor having a base terminal, a collector terminal and an emitter terminal, wherein the emitter terminals of the output transistors are connected to the common main signal conductor, wherein each of the output signal lines to a collector terminal of a Output transistor is connected, wherein the base terminals of the output transistors are each connected to a common ground terminal and wherein each of the collector terminals of the output transistors is connected to a respective output switching signal line, which is acted upon by an output switching signal.

The multi-channel switching device is used in a motor vehicle and serves in particular for data transmission in the context of a driver assistance system, for example, from a detection unit of the driver assistance system to a control unit thereof.

It results from the inventive circuit a very elegant solution to the problem with simple means. In the minimum case, only a single input transistor is provided for each input signal line, and for each output signal line, if there are a plurality of output signal lines, multiple output transistors can be dispensed with and are preferably combined in a single output transistor. (In the presence of only one output signal line, the output transistor can be omitted, as well as in the presence of only one input signal line of the input transistor can be omitted, since in these cases the output side / input side no channel switching is required.) Thus on the one hand, a fast switching on the other hand low system noise is realized. Switching from one channel to another is possible by a simple control of the individual input transistors and / or output transistors by means of switching signals, for example, from a corresponding control device. Thus, the individual transistors can be switched through for signal transmission. Due to the small number of semiconductors also a low power consumption and high isolation of the individual channels against each other, that is, a low crosstalk between the channels realized. The circuit of each input and Output transistors, for example, caused by the setting of the respective base current. If no base current flows, the corresponding input and output transistors do not amplify and leave no signal. Only when setting the corresponding necessary base current through the control device of the respective channel / the respective signal line is enabled.

An advantageous embodiment of the invention provides that the Eingangsschaltsignalleitungen are each connected to the base terminals of the connected and for switching on the respective input transistor with an input switching signal for generating a base current can be acted upon.

By switching on the collector current at the respective input transistor, it is switched active so that the signal on the input signal line is switched through.

The invention can also advantageously be configured in that each of the input transistors is assigned a switching transistor, each having a base terminal, a collector terminal and an emitter terminal and that the emitter terminals of the input transistors are each connected to a collector terminal of a switching transistor whose emitter terminal each with a common Ground terminal is connected and that the base terminals of the switching transistors are each connected to an input switching signal line.

This circuit, in which two transistors are provided in the input region of the multi-channel switching device for each input channel / input signal line, offers the same switching options as the basic version, whereby in each case via the adjustment of the emitter current of the respective input transistors by means of the switching transistors a shorter switching time is achieved compared to the basic version, in which the base current of the respective input transistors is controlled.

The invention can also advantageously be configured in that the input transistors and / or the output transistors and / or the switching transistors are designed as field-effect transistors. This achieves an even lower power and possibly even faster switching of the channels.

A further advantageous embodiment of the invention provides that the main signal conductor is connected to the emitter terminal of a control transistor whose collector terminal is connected to a supply voltage terminal and whose base terminal is connected to a control signal terminal for controlling the gain of the multi-channel switching device.

With this circuit, a simple and low-noise setting of the gain of the switching device by means of a control signal voltage is possible by the control transistor. It is for this purpose no separate module provided, but the control transistor is integrated in a simple manner in the circuit.

A further advantageous embodiment of the invention provides that the control transistor is designed as a field effect transistor.

The invention can also advantageously be configured in that a power measuring device is provided at the collector terminal of the control transistor.

Through the power measuring device, the gain of the circuit can be optimally adjusted to achieve exactly the required power or signal strength at the outputs, so that the minimum necessary gain can be adjusted and thus the power consumption and the noise performance of the entire circuit can be optimized.

For the embodiment of the power measuring device can be advantageously provided that this has a device for coupling out AC voltage at the collector terminal of the control transistor. By way of example, this device can have a capacitor which suppresses the DC voltage component and transmits the AC voltage component. The capacitor can be followed by a rectifier diode in series, behind the detection of the AC voltage amplitude in a simple form is possible. The side facing away from the capacitor side of the rectifier diode can also be connected via a resonant circuit to the ground potential to output fundamental oscillations that have nothing to do with the signals to be switched, for example, humming, and short-circuit to ground.

A further advantageous embodiment of the invention provides that at least two input and at least two output signal lines are provided with responsive input and output transistors.

The present circuit enables the achievement of advantages, especially with multiple input and output channels. In this case, the efficiency of the circuit with few switching elements can fully exploit their advantages.

The invention can also be advantageously configured by a Drive device for the output of input switching signals and / or output switching signals for activating the input signal lines and / or output signal lines is provided.

By means of such a drive device, which can also be designed, for example, as a digital circuit or microcontroller, the desired input channels / input signal lines can be switched through to desired output channels / output signal lines by means of the multichannel switching device in a simple manner and also in dependence on external control signals. Due to the high efficiency and low-power control of the multi-channel switching device and the drive device is not burdened with a high output current or a high output power. This also makes a high-frequency operation of the entire circuit possible.

In the following the invention will be shown with reference to an embodiment in a drawing and explained below.

Showing:

1 Schematically a multi-channel switching device with N input channels and M output channels,

2 a multi-channel switching device as in 1 with differently shaped input channels,

3 a multi-channel switching device as in 1 with an additional reinforcement device,

4 a multi-channel switching device as in 2 with an additional amplifying device and a power measuring device,

5 a schematic representation of the multi-channel switching device according to the invention with a drive device.

Identical components are provided in all figures with the same reference numerals and the same lettering lettering.

The 1 schematically shows a multi-channel switching device with N input channels and M output channels. Each input channel has an input signal line 1 . 2 . 3 on which in each case the input signal voltages V ^IN ₁ to V ^IN _N abut.

Each of the input signal lines 1 . 2 . 3 is with each of the base 59 . 60 . 61 an input transistor 4 . 5 . 6 connected. The input transistors are also designated T ^IN ₁ to T ^IN _N. The emitter connections 7 . 8th . 9 the input transistors 4 . 5 . 6 are each connected to a common ground potential. The collector connections 10 . 11 . 12 the input transistors are connected to a common main signal conductor 13 connected.

Each of the input transistors 4 . 5 . 6 is an input switching signal line 14 . 15 . 16 assigned, wherein the input switching signal lines can be acted upon with a switching signal which in the 1 additionally designated by MUX ^IN ₁ to MUX ^IN _N. The respective input switching signal lines 14 . 15 . 16 are with the basic connections 59 . 60 . 61 the input transistors 4 . 5 . 6 connected and as soon as a corresponding input switching signal is applied, the respective input channel / input transistor 4 . 5 . 6 and the input signal V ^IN ₁ to V ^IN _N applied to it becomes the main signal conductor 13 connected through. In this way, the selection of the input signal among the N possible input signals by the input switching signals MUX ^IN takes place.

On the output side, the multi-channel switching device M has Ausgangssleitun conditions 17 . 18 . 19 on which an output signal V ^OUT ₁ to V ^OUT _M may be present.

For this purpose, each of the output signal lines 17 . 18 . 19 each with an output transistor 20 . 21 . 22 connected. The basic connections 62 . 63 . 64 the output transistors 20 . 21 . 22 are each about controllable power sources 23 with a common ground potential 33 connected. The emitter connections 24 . 25 . 26 are each with the main signal conductor 13 connected. The collector connections 27 . 28 . 29 the output transistors are each connected to output switching signal lines 30 . 31 . 32 connected to which output switching signals for switching through the respective output channels / output signal lines may be present. Lies on one of the output transistors 20 . 21 . 22 at the collector terminal an output switching signal MUX ^OUT ₁ to MUX ^OUT _M on, so is a base current in the respective output transistor 20 . 21 . 22 is generated so that the corresponding output transistor turns on and passes a signal. The corresponding output signal line then carries the output signal.

According to the presented circuit concept, the input and output signal lines are thus connected to each other in that in the corresponding input transistor and the desired output transistor, for example, a base current generated by a switching signal and thus the input and the output transistor are switched to passage. If no switching signal is present at the respective transistor, then it blocks.

By a suitable choice of parameters can be with this circuit a small System noise and achieve sufficient gain at sufficient switching frequencies.

In the 2 a multi-channel switching device is shown, wherein the input channels are arranged side by side on the left side and the output channels on the upper side of the circuit, as in the 1 , The input transistors are as in the 1 With 4 . 5 , and 6 designated. At these lie gene the input signal voltages V ^IN ₁ to V ^IN _N on. As with the embodiment used in the 1 is shown, the respective collectors 10 . 11 . 12 the input transistors with the common main signal conductor 13 connected.

Unlike the one in the 1 The circuit shown are the emitter terminals 7 . 8th . 9 the input transistors each with a collector terminal 34 . 35 . 36 a switching transistor 37 . 38 . 39 connected while the emitter terminals 40 . 41 . 42 the switching transistors each having a common ground potential 43 are connected. At the base connections 44 . 45 . 46 the switching transistors 37 . 38 . 39 the input switching signals MUX ^IN ₁ to MUX ^IN _{N are applied} . Will a suitable input switching signal to one of the basic connections 44 . 45 . 46 applied, so a current flows through the corresponding switching transistor 37 . 38 . 39 , which has a corresponding emitter current through the emitter terminal 7 . 8th . 9 of the corresponding input transistor 4 . 5 . 6 of the input channel, causing it to turn on and the input signal to the main signal conductor 13 by guides.

This two-stage transistor circuit per input channel allows a shorter switching time over the modulation of the input channels by means of the base current of the input transistors, as shown in FIG 1 shown.

The 3 shows a circuit which is constructed substantially as in the 2 shown circuit, wherein also with the main signal line 13 and the emitter terminals 24 . 25 . 26 the output transistors 20 . 21 . 22 an emitter terminal 48 a control transistor 47 connected is. The collector connection 49 the control transistor 47 is connected to a supply voltage V _GC , which also supplies the energy that requires a corresponding signal amplification by the switching device.

The gain is achieved by the control of the base current of the control transistor 47 via the base current source 50 controlled, which represents a control signal terminal for the control transistor. The base current source 50 is on its the control transistor 47 opposite side with the common ground connection 43 connected.

By controlling the gain of the multi-channel switching device, an optimized output level of the output channels is adjustable, whereby the noise figure of the system can be optimized. About the adjustable gain, the circuit according to the invention is also adaptable to circuitry requirements in the forwarding of the output signals.

This is because the control transistor 47 is organically inserted into the circuit of the input and output transistors, resulting in low cost, low susceptibility and high efficiency of the overall circuit.

The 4 shows in addition to those in the 3 shown switching elements at the collector terminal 49 the control transistor 47 An institution 51 for power measurement. The total current of the control transistor 47 , which governs the amplification of the output signals, flows through the collector terminal 49 and can thus be used as a measure of the output power. The performance measuring device 51 has a decoupling line 52 on that with the collector connection 49 is connected and into which a capacitor 53 is inserted, which passes only the AC components, that is, the signal components. To the condenser 53 connected in series is a semiconductor diode 54 , which rectifies the signals and thus an amplitude measurement at the power measurement terminal 55 allows at which the power representing voltage V _MAX can be tapped.

In addition, the power measurement connection 55 via a resonant circuit 56 consisting of a capacitor and a coil, which are connected in parallel to each other, with the common ground potential 43 connected. Thus, certain fundamental oscillations, to which the resonant circuit is set, and which have nothing to do with the wanted signals, can be short-circuited.

Overall, the invention realized by the circuit examples explained above allows the construction of a simple low-cost transistor circuit in which all necessary elements can be integrated efficiently, so that the overall function can be implemented at a low cost with a high efficiency and a low noise figure.

In 5 is schematically the multi-channel switching device 57 as a whole in cooperation with a control device 58 shown. The input signal lines 1 . 2 . 3 the multi-channel switching device 57 are shown on the left, while the output signal lines 17 . 18 . 19 are shown on the right side. The input switching signal lines 14 . 15 . 16 connect the drive device 58 with the multi-channel switching device 57 , In addition, between the drive device 58 and the switching device 57 the output switching signal lines 30 . 31 . 32 (It goes without saying that the number of input channels and output channels shown in the figures can vary from 1 to N for the input channels and 1 to M for the output channels, respectively). The drive device 58 For example, it may include a microprocessor or a microcontroller that generates appropriate input switching signals and output switching signals according to the requirements of the signal distribution to bring the multi-channel switching device into the desired coupling state. In addition, the drive device 58 Also have output lines, with the help of the gain of the control transistor in the multi-channel switching device 57 can be adjusted.

The drive device 58 can also have an input to which the power measurement terminal 55 the power measuring device 51 can be connected.

LIST OF REFERENCE NUMBERS

1

 Input signal line

2

 Input signal line

3

 Input signal line

4

 input transistor

5

 input transistor

6

 input transistor

7

 Emitter of the input transistors

8th

 Emitter of the input transistors

9

 Emitter of the input transistors

10

 Collector of the input transistors

11

 Collector of the input transistors

12

 Collector of the input transistors

13

 Main-signal circuit

14

 Input switching signal line

15

 Input switching signal line

16

 Input switching signal line

17

 Output signal line

18

 Output signal line

19

 Output signal line

20

 output transistor

21

 output transistor

22

 output transistor

23

 controllable power source

24

 Emitter of the output transistors

25

 Emitter of the output transistors

26

 Emitter of the output transistors

27

 Collector of the output transistors

28

 Collector of the output transistors

29

 Collector of the output transistors

30

 Output switching signal line

31

 Output switching signal line

32

 Output switching signal line

33

 common ground potential

34

 Collector of switching transistors

35

 Collector of switching transistors

36

 Collector of switching transistors

37

 switching transistor

38

 switching transistor

39

 switching transistor

40

 Emitter of the switching transistors

41

 Emitter of the switching transistors

42

 Emitter of the switching transistors

43

 common ground potential

44

 Basic connection of the switching transistors

45

 Basic connection of the switching transistors

46

 Basic connection of the switching transistors

47

 regulating transistor

48

Emitter connection of 47

49

Collector connection of 47

50

Control signal connection / base current source for 47

51

 Power measurement device

52

 decoupling line

53

 capacitor

54

 Semiconductor diode

55

 Performance measurement connection

56

 resonant circuit

57

 Mehrkanalumschalteinrichtung

58

 driving

59

 Basic connection e. input transistor

60

 Basic connection e. input transistor

61

 Basic connection e. input transistor

62

 Basic connection e. output transistor

63

 Basic connection e. output transistor

64

 Basic connection e. output transistor

65

 Supply voltage connection

Claims (10)

Electronic multichannel switching device in a motor vehicle, in particular for a driver assistance system, having either a plurality of parallel input signal lines ( 1 . 2 . 3 ) and one or more output signal lines ( 17 . 18 . 19 ) or with several output signal lines ( 17 . 18 . 19 ) and one or more input signal lines ( 1 . 2 . 3 ), wherein in the presence of multiple input signal lines ( 1 . 2 . 3 ) of each input signal line ( 1 . 2 . 3 ) a bipolar input transistor ( 4 . 5 . 6 ) each having a base connection, a collector connection ( 10 . 11 . 12 ) and an emitter terminal ( 7 . 8th . 9 ), each of the input signal lines ( 1 . 2 . 3 ) with the basic connection ( 59 . 60 . 61 ) each of an input transistor ( 4 . 5 . 6 ), the emitter terminals ( 7 . 8th . 9 ) of the input transistors ( 4 . 5 . 6 ) with a common ground potential connection ( 43 ), the collector terminals ( 10 . 11 . 12 ) of the input transistors ( 4 . 5 . 6 ) with a common main signal conductor ( 13 ) and each input transistor ( 4 . 5 . 6 ) by means of an input switching signal via an input switching signal line ( 14 . 15 . 16 ) is transferred from a signal blocking state to a signal conducting state in the presence of at least two output signal lines ( 17 . 18 . 19 ) each output signal line ( 17 . 18 . 19 ) an output transistor ( 20 . 21 . 22 ) each with a basic connection ( 62 . 63 . 64 ), a collector terminal ( 27 . 28 . 29 ) and an emitter terminal ( 24 . 25 . 26 ), the emitter terminals ( 24 . 25 . 26 ) of the output transistors ( 20 . 21 . 22 ) with the common main signal conductor ( 13 ), each of the output signal lines ( 17 . 18 . 19 ) with a collector terminal ( 27 . 28 . 29 ) of an output transistor ( 20 . 21 . 22 ), the basic connections ( 62 . 63 . 64 ) of the output transistors ( 20 . 21 . 22 ) each with a common ground connection ( 33 ) and wherein each of the collector terminals ( 27 . 28 . 29 ) of the output transistors ( 20 . 21 . 22 ) each having an output switching signal line ( 30 . 31 . 32 ), which can be acted upon by an output switching signal. Multi-channel switching device according to claim 1, characterized in that the input switching signal lines ( 1 . 2 . 3 ) each with the basic connections ( 59 . 60 . 61 ) of the input transistors ( 4 . 5 . 6 ) and for switching on the respective input transistor ( 4 . 5 . 6 ) can be acted upon by an input switching signal for generating a base current. Multi-channel switching device according to claim 1, characterized in that each of the input transistors ( 4 . 5 . 6 ) one switching transistor each ( 37 . 38 . 39 ), each with a basic connection ( 44 . 45 . 46 ), a collector terminal ( 34 . 35 . 36 ) and an emitter terminal ( 40 . 41 . 42 ) and that the emitter terminals ( 7 . 8th . 9 ) of the input transistors ( 4 . 5 . 6 ) each with a collector terminal ( 34 . 35 . 36 ) of a switching transistor ( 37 . 38 . 39 ) whose emitter terminal ( 40 . 41 . 42 ) each with a common ground connection ( 43 ) and that the basic connections ( 44 . 45 . 46 ) of the switching transistors ( 37 . 38 . 39 ) each having an input switching signal line ( 14 . 15 . 16 ) are connected. Multi-channel switching device according to one of Claims 1 to 3, characterized in that the input transistors ( 4 . 5 . 6 ) and / or the output transistors ( 20 . 21 . 22 ) are formed as field effect transistors. Multi-channel switching device according to one of claims 1 to 4, characterized in that the main signal conductor ( 13 ) with the emitter terminal ( 48 ) of a control transistor ( 47 ) whose collector terminal ( 49 ) with a supply voltage connection ( 65 ) and whose base terminal is connected to a control signal terminal ( 50 ) is connected to control the gain of the multi-channel switching device. Multi-channel switching device according to claim 5, characterized in that the control transistor ( 47 ) is designed as a field effect transistor. Multi-channel switching device according to claim 6, characterized in that at the collector terminal ( 49 ) of the control transistor ( 47 ) a power measuring device ( 51 ) is provided. Multi-channel switching device according to claim 7, characterized in that the power measuring device ( 51 ) a device ( 52 . 53 ) for decoupling AC voltage at the collector terminal ( 49 ) of the control transistor ( 47 ) having. Multi-channel switching device according to one of claims 1 to 8, characterized in that at least two input signal lines ( 1 . 2 . 3 ) and at least two output signal lines ( 17 . 18 . 19 ) are provided. Multi-channel switching device according to one of claims 1 to 9, characterized in that a drive device ( 58 ) for the output of input switching signals and / or output switching signals for activating the input signal lines ( 1 . 2 . 3 ) and / or output signal lines ( 17 . 18 . 19 ) is provided.

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