DE102008008160A1 - Electrical component i.e. satellite/assistance sensor, supplying method for e.g. passenger protective system in vehicle, involves controlling voltage potential on return line such that voltage difference remains under predetermined value - Google Patents

Abstract

The method involves connecting an electrical component i.e. satellite/assistance sensor (3), with a voltage electrical system via an outgoing wire (8.1) and with a direct current voltage drain via a return wire (8.2). A voltage potential on the return line is controlled, such that a voltage difference (DeltaU) between the outgoing wire and the return wire remains under a predetermined value. A zener diode is connected in a supply unit between and the outgoing wire and the return wire, such that zener diode is permeable during a voltage difference at the predetermined value. Independent claims are also included for the following: (1) a supply unit for supplying an electrical component in a vehicle from a direct current voltage electrical system (2) a control device for passenger protective system.

Description

The The invention relates to a method for supplying an electrical Assembly in a vehicle according to the preamble of claim 1.

In The automotive industry is gaining electronic systems to increase the Safety, such as occupant protection systems to increase the safety of vehicle occupants or brake assist systems, to optimize the brake functionality or braking distance more and more important.

to Ensuring the system requirements, such as the required fast tripping times in the occupant protection systems It has become the state of the art that such Occupant protection systems from a preferably centrally arranged Control unit (central unit), and a plurality of so-called outsourced assistance sensors (outsourced Satellites), which are usually close to the vehicle's outer skin are arranged, are realized.

The Assistance sensors for occupant protection systems can based on different principles of action. Mostly However, for this purpose, sensors are used, which are based on acceleration or pressure respond.

As well The state of the art belongs to the brake assist systems so-called wheel speed sensors, which are outsourced sensors located directly on site at the braking facilities, for example in conjunction with the brake electronic system an ABS functionality to be able to represent or fulfill.

The Assistance sensors for brake assist systems are in the Rule a bit easier realized and are mostly based on this the principle of a Hall effect, or it get here so-called Hall sensors for use.

A Common feature of these different assistance sensors is in it to see that all assistance sensors record data or information, and this collected information or data, via interface to the respective "central control unit" or corresponding "central electronics" transmitted.

When Central unit or central electronics are here the units to understand, in this the actual algorithm (μC) is implemented, these units are not necessarily must be located in the center (center) of the vehicle. For the sake of simplicity, only the term "central device" will be used below. used.

Based the multitude of these assistance sensors in the vehicle become the interfaces usually realized as so-called two-wire interfaces, to limit the cabling effort to the bare minimum to be able to. The special feature of these so-called two-wire interfaces can be seen in the fact that by means of this interface both the energy supply of the assistant sensor as well as the data transfer from Assistance sensor to the central unit takes place by the to be transmitted Data from the assistant sensor by current modulation to that of the central unit provided supply current can be modulated.

From the Scriptures DE 196 09 290 C2 For example, an airbag system is known, in which by means of current modulation in a two-wire interface, the data is transmitted from the assistance sensors to the central device.

From the Scriptures DE 103 21 679 B4 For example, another occupant protection system is known, in which by means of current modulation in a two-wire interface, the data from the assistance sensors are transmitted to the central unit.

When Disadvantage of all these disclosed implementations can be considered be that the assist sensors on an increased Must have dielectric strength to be resistant against leaks and short circuits against live conductors To be lines, especially if these lines increased Have voltage potential to vehicle mass, since according to relevant vehicle specification requirements All cables short-circuit proof against vehicle ground and vehicle battery have to be realized.

These Demand ultimately means that the assistance sensors or the therein electronic circuits / components (usually realized as ASIC / semiconductor) according to the state the technology must have a dielectric strength of about 30 volts, resistant to a short circuit to a live line to be when at the same time the operating state "Jump-Start" is present.

The The object of the invention is therefore to present a solution which makes it possible for the realization of the assistance sensors inexpensive semiconductor processes are used can and on the other hand, the total dielectric strength remains guaranteed.

This object is solved by the features of the independent claims. Advantageous developments of the invention will become apparent from the dependent claims, wherein also combinations and developments of individual features with each other are bar.

These The object is achieved by the features of the independent claims solved. Advantageous developments of the invention result are from the subclaims, including combinations and further developments of individual features are conceivable with each other.

One essential idea of the invention is that the mass return the two-wire interface, depending on the actual existing voltage on the supply line of the two-wire interface, changed in terms of style or adjusted / tracked so that the resulting difference between the two wires of the two-wire interface, to none Time can exceed a predetermined threshold voltage.

The Invention will now be described below with reference to embodiments explained in more detail with the aid of the figures. The following may be for functionally same and / or the same elements with the same reference numerals. It demonstrate:

The Drawings show in

1 : A schematic representation of a central device with an outsourced satellite, as well as its connection to the central device by means of a two-wire interface, according to the prior art.

2 : A principle representation analogous to the 1 showing a short circuit of the two-wire interface with respect to a live line.

3 : A schematic representation of a first inventive solution example

4 : A schematic representation of a second inventive solution example.

5 : A schematic representation of a third inventive solution example.

The 1 shows a schematic representation of a central device ( 2 ) with an outsourced satellite ( 3 ) as a module to be supplied and its connection to the central device by means of a two-wire interface ( 8.1 . 8.2 ) according to the prior art.

As can be seen from the figure, the central device ( 2 ) (ECU / control unit) by means of two lines 5.1 (UBatt) and 5.2 (Mass) connected to the vehicle electrical system, in order to use the central unit internal power supply ( 2.2 ), which generates the voltages required by the system. As can also be seen from the figure, the central device has a voltage source ( 2.3.1 ), to supply the assistance sensor / satellite ( 3 ), as well as a power conditioning circuit ( 2.3.2 ), for detecting the modulated current on the supply line ( 8.1 ), on. The thus determined current signal information is the μC ( 2.1 ) for further processing. The voltage source ( 2.3.1 ) and the power conditioning circuit ( 2.3.2 ) are preferably ASIC ( 2 ) or semiconductor circuit ( 2 ) realized.

The assistant sensor ( 3 ) or satellite ( 3 ), as well as the central device is shown only in principle, and consists of the sensor element ( 3.2 ), a μC ( 3.1 ) (alternatively a hard-wired logic), and a current modulation unit ( 3.3 ), by means of this the satellite supply current on the supply line ( 8.1 ) a current signal information ( 4 ) can be modulated. The ground return line ( 8.2 ) of the two-wire interface, is in the central 2 ) connected directly or with low impedance to ground.

The 2 shows a schematic representation analogous to 1 , where a short circuit ( 6 ) on the positive supply line ( 8.1 ) of the two-wire interface with respect to a live line ( 7 ) is shown. As can be further seen from the illustration, the line ( 7 ), which typically carries the vehicle battery voltage (tolerance range of 6 V to 16.5 V), in the case of a "jump start" have 27 volts potential, this voltage due to the short circuit ( 6 ) then on the sensor ( 3 ) pending.

The 3 shows a schematic representation of a first inventive solution example to obtain the desired effect. As can be seen from the figure, the mass return ( 8.2 ) of the two-wire interface, depending on the actual voltage present on the supply line ( 8.1 ) of the two-wire interface, in terms of voltage with the control unit ( 2.4 ) is changed in the type or adapted / tracked, so that the resulting difference between the two lines ( 8.1 . 8.2 ) of the two-wire interface, at any time can not exceed a predetermined threshold voltage, wherein the desired or maximum allowable differential voltage by means of the zener diode ( 2.5 ) is given.

As can be seen from the illustration, the control unit ( 2.4 ) in conjunction with the zener diode ( 2.5 ) the potential of the ground return ( 8.2 ) of the two-wire interface held in principle as long as against ground, as long as the voltage difference between the two lines ( 8.1 . 8.2 ) of the Two-wire interface the zener voltage of the Zener diode ( 2.5 ) has not reached. Takes the supply line ( 8.1 ) of the two-wire interface, however, a voltage which is greater than the Zener voltage of the Zener diode ( 2.5 ), so in principle the potential of the ground return ( 8.2 ) of the two-wire interface continuously by means of the control unit ( 2.4 ) by the amount tracked to this the potential on the supply line ( 8.1 ) of the two-wire interface, the zener voltage of the Zener diode ( 2.5 ) exceeds.

In addition to the advantage that by means of this realization in the central device ( 2 ), the assistant sensor ( 3 ) or satellite ( 3 ) (in compliance with the relevant automotive specification requirements), only a limited dielectric strength (significantly less than 27 volts) must have, and thus cheaper semiconductor processes can be used in the satellite implementation, in addition to the voltage ruggedness another advantage can be obtained , which is to be seen in that additionally also an additional data transmission robustness against single errors can be obtained, if (as not further shown), also in the control unit ( 2.4 ) a power conditioning circuit ( 2.3.2 ) is implemented for detecting the modulation current, since then in this case (error), then the evaluation of the modulation current via the ground return line ( 8.2 ) of the two-wire interface can be done. The advantages mentioned are in an analogous manner, also by means of the following solution examples according to the 4 and 5 reachable.

The 4 shows a schematic representation of a second inventive solution example to obtain the desired effect. As can be seen from the figure, the mass return ( 8.2 ) of the two-wire interface, depending on the actual voltage present on the supply line ( 8.1 ) of the two-wire interface, in terms of voltage with the control unit ( 2.6 ) changed in style or adapted / tracked, so that the resulting difference between the two lines ( 8.1 . 8.2 ) of the two-wire interface, at any time can not exceed a predetermined threshold voltage, wherein the desired or maximum allowable differential voltage by means of the zener diode ( 2.5 ) is given.

As can be seen from the self-explanatory diagram, the control unit ( 2.6 ) in conjunction with the zener diode ( 2.5 ) the potential of the ground return ( 8.2 ) of the two-wire interface held in principle as long as against ground, as long as the voltage difference between the two lines ( 8.1 . 8.2 ) of the two-wire interface the zener voltage of the Zener diode ( 2.5 ) has not reached. Takes the supply line ( 8.1 ) of the two-wire interface, however, a voltage which is greater than the Zener voltage of the Zener diode ( 2.5 ), so in principle the potential of the ground return ( 8.2 ) of the two-wire interface continuously by means of the control unit ( 2.6 ) by the amount tracked to this the potential on the supply line ( 8.1 ) of the two-wire interface, the zener voltage of the Zener diode ( 2.5 ) exceeds.

The 5 shows a schematic representation of a third inventive solution example, to obtain the desired effect. As can be seen from the figure, the mass return ( 8.2 ) of the two-wire interface as a function of the actual voltage present on the supply line ( 8.1 ) of the two-wire interface, in voltage with the current sink ( 2.8 ) in conjunction with the zener diode ( 2.7 ) is changed in the type or adapted / tracked, so that the resulting difference between the two lines ( 8.1 . 8.2 ) of the two-wire interface, to none. Time may exceed a predetermined threshold voltage, wherein the desired or maximum allowable differential voltage by means of the zener diode ( 2.7 ) is given.

As can be seen from the self-explanatory illustration, the current sink ( 2.8 ) in conjunction with the zener diode ( 2.7 ) the potential of the ground return ( 8.2 ) of the two-wire interface held in principle as long as against ground, as long as the voltage difference between the two lines ( 8.1 . 8.2 ) of the two-wire interface the zener voltage of the Zener diode ( 2.7 ) has not reached. Takes the supply line ( 8.1 ) of the two-wire interface, however, a voltage which is greater than the Zener voltage of the Zener diode ( 2.7 ), so in principle the potential of the ground return ( 8.2 ) of the two-wire interface continuously by means of the Zener diode ( 2.7 ) by the amount tracked to this the potential on the supply line ( 8.1 ) of the two-wire interface, the zener voltage of the Zener diode ( 2.7 ) exceeds.

All three solutions shown have in common that to achieve a balanced distribution of power dissipation on the ASIC ( 2 ) the power loss in a manner not shown by suitable circuit measures, depending on the two components voltage source ( 2.3.1 ) as well as control unit ( 2.4 . 2.6 ) or current sink ( 2.8 ), can be divided in percentages as desired.

Finally, the completeness should be noted that, as already mentioned, it is not necessarily the mentioned central devices are electronic systems, which must necessarily be located directly in the center (center) of the vehicle, but that the electronics can also be arranged offset from the center, as well as in the outsourced satellites (assistance sensors) within the meaning of the invention can act to any type of assemblies, which are realized as compared to the housing potential-free two-pole electronics, and by means of a two- Wire interface are connected to the central unit.

1

Occupant protection system with central unit and satellite

2

central unit (Control unit)

2.1

.mu.C

2.2

AC adapter / power conditioning

2.3

ASIC / Semiconductors

2.3.1

voltage source

2.3.2

Power conditioning circuit

2.4

control unit

2.5

Zener diode

2.6

control unit

2.7

Zener diode

2.8

current sink

3

Satellite / Assistance sensor

3.1

.mu.C

3.2

sensor

3.3

Current modulation unit

4

Information / data in the form of a modulated stream

5.1

Onboard power supply "Plus" / UBatt. (Terminal 15)

5.2

Onboard power supply "ground" (Vehicle structure)

6

short circuit

7

checking live management

8.1

supply line the two-wire interface

8.2

Ground return line the two-wire interface

⟘

ground potential

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 19609290 C2 [0010]
• - DE 10321679 B4 [0011]

Claims (5)

Method for supplying an electrical assembly ( 3 ) in a vehicle from a DC electrical system ( 5.1 ), whereby the module is connected via an 8.1 ) with the DC electrical system and via a return line ( 8.2 ) is connected to a DC voltage sink (⟘), characterized in that the voltage potential on the return line ( 8.2 ) is controlled so that the voltage difference (ΔU) between the forward and return lines remains below a predetermined value. Supply unit for supplying an electrical assembly in a vehicle from a DC electrical system ( 5.1 ), whereby the module is connected via an 8.1 ) with the DC electrical system and via a return line ( 8.2 ) with a DC voltage sink (⟘, 2.8 ), characterized in that means for detecting the voltage difference (ΔU) between the forward and return lines and means for controlling the voltage potential on the return line ( 8.2 ) are provided as a function of the detected voltage difference (ΔU). Supply unit according to claim 2, characterized in that the DC voltage sink (⟘, 2.8 ) is designed so controllable that the voltage difference (.DELTA.U) between the forward and the return line remains below a predetermined value. Supply unit according to claim 2 or 3, characterized in that in the supply unit between the forward and the return line, a zener diode ( 2.5 . 2.7 ) is switched so that it is permeable to a voltage difference above the predetermined value. Control unit for occupant protection system with a supply unit according to one of the preceding claims.