Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
  • G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections

Definitions

• the present invention relates to a method and a circuit arrangement by means of which a state of loads connected in particular to low-side or high-side switches can be diagnosed.
• Integrated circuit breakers are often designed as so-called low-side switches, in which a switching connection to a predetermined low potential is usually switchable by means of a power transistor. This serves to control a load connected to the switching connection, for example a switching relay, which has to switch particularly high currents or voltages.
• a low-side switch connects a load at an operating voltage potential to ground.
• the respective switching connection can be set to a given high potential via a switching transistor in order to control the respective load.
• a high-side switch may connect a grounded load to the operating voltage potential.
• EMC electromagnetic compatibility
• a buffer capacitor must be connected to the switching connection in the rule.
• Such circuit breakers are used in particular in the automotive sector.
• a method for detecting the state of a load device which can be connected to a switching connection wherein the switching connection can be coupled to a predetermined switching potential and decoupled.
• a connectedness of the load at the switching terminal a non-recognized connectedness of the load on the switching connection or a short circuit between the wiring terminal and a first or a second switching potential in response to a clamping ⁇ voltage drop of the switching connection.
• ⁇ is equal to a decoupling of the switching connection of the predetermined switching potential an additional power source connected to the switching connection.
• a capacitor is provided between the switching connection and the first switching potential, by means of which the voltage drop is determined.
• an additional power source ⁇ is briefly switched on, the supports as a respective charging or discharging a capacitor connected to the switching connection and accelerated. So ⁇ reached at play, in the open-load case, the switching terminal quickly one example known diagnostic potential.
• the additional current source for a Popemm ⁇ th filter period is connected to the switching terminal.
• the additional current source for a Popemm ⁇ th filter period is removed from the switch port, if a measured at the switching terminal corresponds to a measurement potential diagnostic sepotenzial.
• the diagnostic potential can be so ge ⁇ selected, for example, that in the case of an open-load situation, the diagnostic potential must be run from the measuring potential through ⁇ to near, ⁇ represent a potential equilibrium or to ensure a charge equalization of the stored charge off of the capacitor ,
• the method comprises the following method ⁇ steps of:
• the present tapped at the switching terminal measurement potential and ver ⁇ aligned with the diagnostic potential is, for example, the present tapped at the switching terminal measurement potential and ver ⁇ aligned with the diagnostic potential.
• the predetermined filter period is chosen such that it can be brought to the reference potential by charging or discharging of the capacitor within the filter period by means of the Matters ⁇ th reference potential, and the auxiliary power source of the switchgear circuit, is a particularly high diagnostic or switching frequency for a given corresponding switching device, as by the connection of the additional power source, a particularly fast charging or discharging of the capacitor is possible.
• the respective diagnosis potential can be selected such that it is reached by the measurement potential before the reference potential.
• the load device is be- see the switching terminal and a ground potential as a pre ⁇ input switching potential is provided, and the switch terminal can be coupled by means of a controllable switch to a battery potential.
• the switch terminal can be coupled by means of a controllable switch to a battery potential.
• a non-connection of the load device to the switching connection and / or to the ground potential is detected if the measurement potential within the filter period is within a predetermined open-load potential range.
• the capacitor in particular via the additional current source, discharges rapidly, so that the reference potential would have to be set at the switching connection.
• the Diagnosepo ⁇ potential is then preferably above the Referenzpotenzi ⁇ as.
• the open-load potential range can then be defined as a voltage between an upper and a lower diagnostic potential.
• the shoulder to load ⁇ direction between the switching terminal and a Batteriepo ⁇ potential as the predetermined switching potential is provided, and the switch terminal can be coupled by means of a controllable switch to a ground potential. In this case, it is detected after the decoupling of the load device from the ground potential, a Dolphinundensein the load device to the switching terminal, and / or with the battery potential, if the measured potential of the filter period potential range is intra ⁇ half in a predetermined Open-Load.
• the capacitor is rapidly charged in particular by the set power source to ⁇ , so that the reference would have to stop potential in the switching terminal.
• the diagnostic ⁇ potential then is preferably below the Referenzpo ⁇ tenzials. As soon as the diagnosis potential is reached, the additional current source is switched off and a diagnostic result is provided.
• a circuit arrangement for detecting the state of a load device connectable between a switching connection and a first switching potential comprises:
• This circuit arrangement forms, for example, a high-side switch with a rapid diagnostic option for the load state.
• a circuit arrangement for detecting the state of a load device which can be connected to a switching connection is provided, with:
• controllable switch connected between the switching terminal and a first switching potential
• the load device can be connected between the switching connection and a second switching potential.
• This embodiment is particularly suitable for a low-side switch, which also allows a short filter time and thus a high switching frequency.
• the jewei ⁇ celled controllable switch as a MOSFET, in particular as a P or N-channel MOSFET is executed.
• the first and second current source and / or the additional current source are designed as switchable controllable current sources.
• a capacitor is further provided, which is connected between the switching terminal and the first switching potential.
• a control device coupled to the switching connection is provided, which is embodied such that an inventive device is provided. driving for detecting the state of the connectable to the switching terminal load device is performed.
• control device advantageously has a comparison device for comparing the measurement potential with the diagnosis potential.
• the circuit arrangement is designed as an integrated high-side switch or low-side switch, wherein the controllable switch, the first and second current source, the additional current source and the control ⁇ device are integrally formed on a chip.
• Figure 1 a first embodiment of the circuit arrangement according to the invention
• Figure 2 a variant of the method according to the invention
• FIG. 3 voltage curves for the first embodiment of the circuit arrangement
• FIG. 4 shows a second embodiment of the circuit arrangement according to the invention
• FIG. 5 voltage curves for the second embodiment of the circuit arrangement
• FIG. 6 a third embodiment of the circuit arrangement according to the invention. Unless otherwise specified, the same or functionally identical elements have been provided with the same reference symbol in the figures.
• the circuit arrangement 1 shows a first embodiment of a circuit arrangement for detecting the state of a connectable to a switching terminal load device is shown as a high-side switch.
• the circuit arrangement 1 has a control input 12 and a switching connection 5.
• a load device 2 is connected, which is, for example, connected between the switching port 5 and a ⁇ ers th switching potential that is selected here as a ground potential GND.
• a buffer capacitor 3 is connected, which buffers voltage spikes and thus the electromagnetic ⁇ compatibility of the high-side switch with guaranteed ⁇ tet.
• a controllable switch 4 embodied as a power MOSFET transistor is provided, which has a control terminal or gate terminal 13 and a controllable path between a source terminal 14 and a drain terminal 15.
• the drain terminal 15 is connected to a second switching potential VBR which, for example, has a battery potential VBR of 12 volts of a car battery derived from a battery voltage.
• the source terminal 14 is connected to the switching terminal 5.
• a logic control signal CTR to the gate terminal 13 can be coupled, whereby the switching transistor 4, the controllable path either opens or closes and thus triggers a coupling of the switching terminal 5 to the Batteriepotenzi ⁇ al VBR, or a decoupling causes at logical low level on the controllable terminal 13.
• the load device 2 can thus be coupled between the ground potential GND and the battery potential.
• a first and second current source 6, 8 intended.
• the first current source 6 is connected between the Lei ⁇ processing node 16 and a first Einstellpotenzial VN via a controllable switch.
• the second current source 8 is switchable between the line node 16 and a second on-potential VP by means of a controllable switch 9.
• the switches 7, 9 are controlled by a control device 22 such that a constant reference potential VREF is applied to the line node 16.
• the control device 22 is coupled to the line node 16 and outputs control signals CT1, CT2 to the switches 7, 9.
• Typischerwei ⁇ se is the first Einstellpotenzial VN to 0 volts, so set mass and the second Einstellpotenzial VP is at a logic level of 5 volts.
• first and second current sources 6, 8 are usually dimensioned to be approximately 0.1 mA, when the current sources 6, 8 are connected, a reference potential of 2.5 volts is produced at the line node 16 or the switching connection 5.
• an additional current ⁇ Source 10 which is connectable via a switch 11 between the first adjustment potential VN and the switching terminal 5 is provided.
• This additional current source 10 has a dimensioning of 20 mA in an exemplary embodiment.
• a first step S1 the transistor 4 is switched off via the control signal CTR, ie the switching connection 5 is decoupled from the battery potential VBR.
• the switch 11 is closed in step S2 so that the capacitor 3 can be discharged via the additional current source 10 if the load 2 has been disconnected from the switching connection 5.
• This can be done for example by a loose line in the engine or wiring harness of a vehicle.
• the filter time T is started, which determines the period for the diagnosis. T is z. B. chosen so that in an open-load situation with auxiliary power supply 10 switched on within this filter time T, the potential V2 at the switching connection 5 can be set.
• step S3 the potential present at the switching connection 5 is measured as the measuring potential VM and it is checked whether this is within the open-load potential range V2-V1.
• V2 can be for example 3 volts and Vl 2 volts. It can be determined from the comparison result or the time profile of the measurement potential VM, for example, if ⁇ an open-load error is present, ie the load device 2 is not connected to the switching terminal 5. If the Diag ⁇ nosepotenzial V2 is reached, the auxiliary power source 10 is turned off at step S4. In this case, an unconnected load 2 must be present. However, if VM is not within V2-V1, it is checked in step S5 whether the filter ⁇ time period T has expired.
• step S5 is performed again. If it is determined that the filter time has elapsed and the potential measurement has not approached to the diagnosis potential V2 can be ge ⁇ concluded that no error state of the load device is present. At the same time after the filter time T has expired in step S4, the additional current source. In lockable ⁇ sequent step S6, a corresponding diagnosis result is output. On the other hand, if step S4 has been initiated, an open-load error is diagnosed in step S6.
• FIG. 3 shows voltage waveforms of the potential Messpotenzi ⁇ as VM and the timing of switching of the additional current source and the filter time T schematically.
• the switching transistor 4 switches the switching terminal VM and the load device 2 coupled thereto to the battery potential VBR.
• the time ⁇ point to the transistor 4 is turned off, ie the switchgear ⁇ circuit 5 is disconnected from the battery potential VBR. This is controlled via the control signal CTR.
• the condenser 3 must first be discharged to the advertising adjusts the reference potential VREF of 2.5 volts to the switching connection. 5
• the dashed curve VMO shows the course of the measured voltage VMO without an additional current source.
• the condensation tor 3 is discharged in this case only slowly over the current source 6, so that only at the time t 2, the Referenzpo ⁇ potential VREF sets and open-load fault could be detected.
• the additional current source 10 is connected via the switch 11 at the same time as the decoupling, this being indicated by the course of the control signal CT3 (see FIG. 6).
• CT3 see FIG. 6
• the additional current source 10 can be switched off again after ti again and with the end of the filter time T, the fault diagnosis can be output.
• a filter time T is set such that, after the filter time T has elapsed, the capacitor 3, which is embodied, for example, in the order of magnitude of 6.8 nF, is reliably discharged when all three current sources 6, 8, 10 are connected in such a way that the open-load Potential range between V2 and Vl is achieved. It can thus be determined at the time to + T, which is considerably earlier than t 2 , whether an open-load situation exists.
• the substantially redu ⁇ ed by switching on the auxiliary power source 10 discharge time of the capacitor 3 allows a significantly ER- creased switching frequency, as with the switch 1 by driving of the gate terminal 13 of the transistor 4 again coupling the battery potential SUC ⁇ gene already at the time ti can.
• By connecting the additional current source 10 only during the implementation of the diagnosis or detection of a present or non-existing error there are hardly any leakage currents.
• the detection of a potential mögli ⁇ chen open-load state of the load device 2 takes place at statically switched off, so decoupled switching connection 5.
• FIG. 4 schematically shows an embodiment of a corresponding low-side switch 100.
• the low-side switch with diagnostic function 100 has a control input 12 and a switching connection 5. Between the switching terminal 5 and the battery potential VBR a Lasteinrich ⁇ device 2 is connected. Between the switching terminal 5 and the Ground potential GND is also an EMV buffer capacitor 3 connected.
• a MOSFET transistor is provided with a control terminal 13, a source terminal 14 and a drain terminal 15, the source terminal 14 being connected to ground GND and the drain terminal 15 being connected to the switching terminal 5 connected.
• a first and a second current source 6, 8 are provided, which are connected in series by means of two switches 7, 9 controlled by a control device 22 between the first setting potential VN and a second setting potential VP.
• a regulated reference potential VREF can thus be tapped off at a line node 16 between the two current sources 6, 8.
• an additional current source 10 between the switching terminal 5 and the second setting potential VP which is for example at 5 volts, via an additional switch 11 switchable.
• FIG. 5 shows a corresponding voltage curve for a measuring potential, which is tapped off at the switching connection 5 can be and the time sequence of switching the Zu ⁇ set current source and the filter time T shown.
• the control signal CTR As described in Be ⁇ train to Figures 1 and 3, at the time to the switch 4 is opened by the control signal CTR, that the controllable path between the source and the drain port 14, 15 of the transistor 4 becomes high. If the load device 2 has been removed, the reference potential VREF of 2.5 volts at the line node 16 or the switching connection 5 connected thereto would have to be set by connecting the two current sources 6, 8 via the switches 7, 9.
• the additional current source 10 is seen before ⁇ , which is connected at the same time with the decoupling of GND via the switch 11 to the switching terminal 5. This results in the solid line for the course of the measurement potential VM.
• the diagnosis potential Vl provides a ⁇ VREF to the switching terminal 5 since the additional current source 10 the con ⁇ capacitor 3 recharges quickly.
• the filter period T can thus be significantly reduced.
• the Arnold Böcklin supplied turn ⁇ te additional current source 10 can be designed as a 2mA current source. With a capacitance of the capacitor 3 6,8nF erge ⁇ ben so diagnostic or switching frequencies from about 5 kHz.
• FIG. 6 shows a third embodiment of the circuit arrangement according to the invention.
• the circuit arrangement 200 embodied as a high-side switch has substantially the same elements of the circuit arrangement 1 shown in FIG.
• control device 22 which a
• Comparator 17 and a controller 20 has.
• the comparator 17 has a first input 18 and a second input 19, the second input 19 being connected to the reference potential VREF.
• the first input 18 of the comparator 17 is connected to the switching connection 5.
• the comparator 17 supplies a comparison result CPR to the controller 20 which supplies control signals CT1, CT2, CT3 to the controllable switches 7, 9, 11 for coupling the first and second current sources 6 and 8 and the additional current source 10.
• the comparator 17 can, for example
• a comparison result CPR indicates that the measurement potential VM is greater than, less than or equal to the diagnostic potential V2.
• the controller 20 of the control device 16 evaluates This result CPR, and provides an error signal ER to a Def ⁇ lerausgang 21 of the circuit arrangement 200.
• the control device 16 is configured such that a erfindungsge ⁇ zeßes method for detecting the state of the load device 2, for example, as explained with reference to FIGS.
• control device 22 with two comparators, each with a measuring potential lower and an upper diagnostic potential Vl, V2 verglei ⁇ chen. It is then possible to determine whether a measuring potential VM is present at the switching connection 5 in the open-load potential range V2-V1.
• a corresponding optional comparator 17 ' with a first and a second input
• the second input 18 ' is connected to the lower diagnostic potential Vl, and the first input 18' to the switching connection 5.
• the inventive circuit arrangement is suitable in particular ⁇ sondere for integration on a semiconductor chip used in the automotive sector, where often circuit breakers are used as high or low side switch.
• the inventive connection of the additional current source results in an improved diagnostic capability for detecting at ⁇ example, open-load states of the provided load device.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Electronic Switches (AREA)
• Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)

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• 2006
  • 2006-09-26 DE DE102006045308A patent/DE102006045308B4/de active Active
• 2007
  • 2007-05-31 US US12/440,928 patent/US8416546B2/en active Active
  • 2007-05-31 WO PCT/EP2007/055330 patent/WO2008037510A1/de active Application Filing
  • 2007-05-31 EP EP07729733A patent/EP2069811A1/de not_active Withdrawn
  • 2007-05-31 CN CN2007800237091A patent/CN101490571B/zh active Active

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