WO2009021775A1 - Switching system - Google Patents

Switching system Download PDF

Info

Publication number
WO2009021775A1
WO2009021775A1 PCT/EP2008/058595 EP2008058595W WO2009021775A1 WO 2009021775 A1 WO2009021775 A1 WO 2009021775A1 EP 2008058595 W EP2008058595 W EP 2008058595W WO 2009021775 A1 WO2009021775 A1 WO 2009021775A1
Authority
WO
WIPO (PCT)
Prior art keywords
signal
switching element
switching
sensor signal
limit
Prior art date
Application number
PCT/EP2008/058595
Other languages
German (de)
French (fr)
Inventor
Volker Husslein
Original Assignee
Continental Automotive Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Continental Automotive Gmbh filed Critical Continental Automotive Gmbh
Publication of WO2009021775A1 publication Critical patent/WO2009021775A1/en

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/08—Modifications for protecting switching circuit against overcurrent or overvoltage
    • H03K17/082—Modifications for protecting switching circuit against overcurrent or overvoltage by feedback from the output to the control circuit
    • H03K17/0822—Modifications for protecting switching circuit against overcurrent or overvoltage by feedback from the output to the control circuit in field-effect transistor switches
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/08—Modifications for protecting switching circuit against overcurrent or overvoltage
    • H03K17/082—Modifications for protecting switching circuit against overcurrent or overvoltage by feedback from the output to the control circuit
    • H03K17/0826—Modifications for protecting switching circuit against overcurrent or overvoltage by feedback from the output to the control circuit in bipolar transistor switches

Definitions

  • high-side and / or low-side switches e.g. for switching lighting or air valves for level control used.
  • a load assigned to the high-side switch is typically connected to the mass of the motor vehicle.
  • This arrangement of the high-side switch with the ground-based load requires a control voltage which is higher than an input voltage supplying the load.
  • smart high-side switches are used, which generate the required control voltage internally.
  • a load associated with the low-side switch is typically connected to the input voltage.
  • the low-side switch is typically ground-referenced, whereby a special control as in the case of the high-side switch is not required.
  • the low-side switch can be designed as well as the high-side switch as a smart switching element.
  • Smart high-side and / or smart low-side switches are short-circuit protected switching elements that are switched off by thermal overload monitoring.
  • This thermal shutdown is typically well above the normal operating range of the switching element, ie the current through the switching element must be correspondingly high, so that the thermal shutdown responds and shuts off the load. Therefore, the corresponding smart high-side switch or smart low-side switch, the associated circuitry, the plug, etc. must be designed for this high overload current, so that no damage to the components and the circuit can occur.
  • the object underlying the invention is to provide a switching system with a switching element that switches off the switching element easily and as quickly as possible in overload operation.
  • the invention is characterized by a switching system with a switching element, which is assigned to a load, and with a drive device having a sensor signal unit, which is designed to determine a sensor signal, which is representative of a load current through the load. Furthermore, the drive device has a limit signal unit which is designed to specify a limit signal, which is representative of a predetermined load current limit of the load current. Furthermore, the drive device has a comparator which is designed to compare the sensor signal applied on the input side with the limit signal applied on the input side and to specify a switching signal dependent on the output side in such a way that when a value of the limit signal is reached by the sensor signal the switching element is switched off.
  • the sensor signal unit is particularly suitable for determining a sensor signal representing a load current. By means of the limit signal unit, a load current limit for the load current can be specified in a particularly suitable manner by means of the limit signal.
  • the comparator is particularly suitable to compare the sensor signal and the limit signal with each other and to specify the switching signal on the output side.
  • the switching element is switched off by means of the switching signal, so that the switching element is not operated unnecessarily long with a current greater than or equal to the value of the load current limit.
  • the comparator is designed as an operational amplifier, wherein the operational amplifier on the input side, the sensor signal and the Stahlsig- signal and the output side, the switching signal is assigned. Due to the operational amplifier, the comparator can be formed particularly simple, inexpensive and reliable.
  • the output of the comparator is designed as an open-collector output. As a result, it is particularly easy to specify the switching signal assigned to the output.
  • the sensor signal unit is designed as a voltage divider and assigned to the switching element and determines the sensor signal as a function of a current through the switching element.
  • the voltage divider makes it possible to determine the sensor signal in a particularly simple and cost-effective manner.
  • the sensor signal unit comprises a reset switching element, which is designed to release the switched-off switching element as a function of the reset signal assigned to the reset switching element.
  • the switching element can be released in a particularly simple manner such that the switching element can be switched on again.
  • the sensor signal unit comprises a capacitor which is arranged and configured as a low-pass filter with one or more resistors associated with the voltage divider, in such a way that the sensor signal is low-pass filtered.
  • the low pass can be made particularly simple.
  • the low-pass filter makes it particularly easy to filter out high-frequency signal components of the sensor signal.
  • the sensor signal U_IS is delayed given by the use of the low-pass filter, whereby short-term current changes of the load current IL, which are in the range of a predetermined by a predetermined dimensioning of the low-pass duration, do not lead to shutdown of the switching element.
  • the limit signal unit comprises a voltage divider.
  • the limit signal is dependent on the output signal applied to the comparator on the comparator.
  • the limit signal is also dependent on the currently valid state of the switching signal, whereby the limit signal can be adapted particularly suitable.
  • this can be specified such that by means of the switching signal, the switching element remains switched off after an overload operation until the switching element is released again by means of the reset signal and can be switched on again.
  • the switching element is designed as a smart high-side switch and / or as a smart low-side switch
  • the sensor signal is dependent on one of the smart high-side and / or the smart low - Side switch associated sensor current, which is representative of a current through the smart high-side and / or the smart low-side switch.
  • the sensor signal can be particularly easily associated with the sensor current of the smart high-side and / or smart low-side switch.
  • the sensor current may be formed in the smart high side or the smart low side switch as a current derived from the current through the switch.
  • the sensor current can also be embodied as the current through the switch, ie the load current.
  • the switching element is designed as a field effect and / or as a bipolar transistor and the sensor signal depends on the current through the corresponding switching element. This makes it particularly easy to represent the current through the corresponding switching element as a sensor signal.
  • Figure 1 shows a circuit arrangement of a switching system with drive device
  • Figure 2 shows another circuit arrangement of a switching system with drive device
  • FIG. It shows the designed as a smart low-side switch switching element Tl, which is associated with a load RL.
  • the load RL is additionally assigned an input voltage V IN, which can be assigned, for example, to a supply voltage of a vehicle electrical system of a motor vehicle.
  • the switching element Tl comprises, in addition to a drain connection D and a source connection S, a switching connection IN, by means of which the switching element Tl can be switched on or off.
  • the drive device CU comprises a sensor signal unit SU, which is arranged between the switching element Tl and the ground GND.
  • the sensor signal unit S_U is assigned a load current IL, which flows through the load RL and the switching element Tl when the switching element T1 is switched on.
  • the load current IL the sensor current IS can be assigned.
  • the sensor signal unit S_U generates a sensor signal U_IS, which is representative of the load current IL.
  • the sensor signal can be designed as current or voltage.
  • the sensor signal unit S_U has a reset signal input for a reset signal S_RESET, by means of which the sensor signal U_IS can be set to ground potential GND, for example.
  • the drive device C_U of the switching element Tl comprises a limit signal unit L_U.
  • a limit signal UL is determined, which is representative of a predetermined load current limit of the load current IL.
  • the limit signal UL can be embodied as a current or voltage and is preferably predetermined such that the load current limit represented by the limit signal UL is smaller than a current limit of the switching element Tl designed as a smart low-side switch.
  • the drive device C_U comprises a comparator COMP on the input side of which the sensor signal U_IS of the sensor signal unit S U and the limit signal UL of the limit signal unit L U are assigned.
  • the comparator COMP is designed to compare the signals present on the input side with one another and, depending on the comparison, to predetermine a switching signal S S1 on the output side.
  • the switching signal S S1 is assigned to the switching terminal IN of the switching element T1.
  • a control unit CTRL is shown in FIG. 1, which is designed, for example, as a microcontroller and controls the drive device C_U.
  • the control unit CTRL is assigned a further switching signal S S2, which is output via a preceding switch signal S S2.
  • the resistor R6 is connected to the switching signal S Sl, whereby the switching element Tl can be switched on or off by means of the further switching signal S_S2.
  • the control unit CTRL is assigned on the input side the switching signal S_S1 of the comparator COMP in order to detect the current status of the drive device CU and thus the status of the switching element Tl.
  • the control unit CTRL is connected on the output side to the sensor signal unit SU by means of the reset signal S RESET.
  • the switching element Tl In normal operation of the switching element Tl, which is characterized in that a load current IL flows through the switching element Tl, which is smaller than the predetermined load current limit, the switching element Tl by means of the further switching signal S_S2 is controlled by the control unit CTRL.
  • the value of the sensor signal U_IS determined by means of the sensor signal unit S_U is smaller than the value of the limit signal UL, whereby the switching signal S_S1 specified on the output side by the comparator COMP releases the further switching signal S_S2.
  • the control unit CTRL turn off the switching element Tl and turn on the switching element Tl again with simultaneous switching on of the reset transistor T_RESET by means of the reset signal S RESET for a predetermined period of time.
  • An overload operation of the switching element Tl is characterized by a load current IL whose value is greater than that of the load current limit.
  • the sensor signal U_IS determined by means of the sensor signal unit S_U represents the current load flow IL.
  • the switching signal S S1 is preset at the comparator COMP such that the further switching signal S_S2 is not further enabled with respect to the switching terminal IN, but is predetermined by the switching signal S S1 and though such that the switching element Tl is turned off.
  • the control device C_U is preferably designed such that the switching element Tl remains switched off until the control unit CTRL releases the further switching signal S_S2 by means of the reset signal S_RESET and the switching element Tl can be switched on again.
  • the switching element T1 is designed as a smart high-side switch. This includes the switching terminal IN by means of which the switching element Tl can be switched on or off. Furthermore, the switching element Tl comprises a load output OUT, which is assigned to the mass-based load RL and over which the full load current IL flows when the switching element Tl is turned on. Furthermore, the switching element Tl comprises a
  • the sensor current IS is derived from the current through the switching element Tl and is typically smaller, e.g. by a factor of 5000, as the current through the switching element Tl.
  • the switching element Tl is fed via the input voltage V_IN.
  • the sensor signal unit S_U in the drive device C U comprises a voltage divider R4, R5, RS, wherein the resistor R4 is assigned a supply voltage VCC, e.g. 5 V.
  • the sensor current IS is fed to the voltage divider R4, R5, RS via a first connection point VK1.
  • the sensor signal U_IS is tapped off via a second connection point VK2.
  • the sensor signal unit S_U comprises a reset switching element T_RESET which is assigned to the sensor signal U_IS and by means of which the
  • Sensor signal U IS can be set depending on the reset signal S RESET to ground potential GND.
  • a first current Il associated with the supply voltage VCC flows through the resistors R4, R5 and RS. Since the resistors R4, R5 and RS are predetermined and their resistance values do not change during the operation of the drive device C_U, the first current Il is corresponding to the predetermined dimensioning of the resistors Fixed R4, R5 and RS.
  • the sensor current IS is additionally fed via the first connection point VK1, which is assigned to the resistor RS designed as a shunt resistor, so that a resulting current flows through the shunt resistor RS from the sum of the first current Il and the sensor current IS, if a load current IL is flowing.
  • the voltage drop across the shunt resistor RS is thus dependent on the sensor current IS.
  • the sensor signal U IS which is tapped as a voltage signal across the resistors R5 and RS, depending on the sensor current IS. Since the
  • Sensor current IS is representative of the load current IL through the switching element Tl
  • the sensor signal U_IS is representative of the load current IL.
  • the limit signal unit L_U comprises a voltage divider with the resistors Rl, R2, R3.
  • the limit signal UL is specified as a voltage signal.
  • the resistor Rl is assigned to the supply voltage VCC.
  • the resistors R2 and R3 are assigned to the resistor R1 and the resistor R2 is connected to the ground GND.
  • About a third node VK3 the limit signal UL is tapped.
  • the limit signal UL is thus dependent on the dimensioning of the resistors Rl, R2, R3.
  • the limit signal UL is also dependent on the respective value of the switching signal S_S1 associated with the resistor R3.
  • the comparator COMP is designed as a voltage comparator with an operating amplifier OPV with an inverted and a non-inverted input.
  • the inverting input of the operational amplifier OPV is assigned the sensor signal U_IS and the non-inverting input the limit signal UL.
  • the output of the comparator COMP is typically formed as an open-collector output and assigned the switching signal S Sl.
  • the drive device CU as already shown in Figure 1, controlled by the control unit CTRL.
  • control unit CTRL prescribes the further switching signal S S2 with a voltage in the amount of the supply voltage VCC, and thus the switching element T 1 is switched on.
  • the switching signal S_S1 is connected to the further switching signal S_S2 by means of the series resistor R6, when the switching signal S_S1 is switched on, the supply voltage potential VCC of the further switching signal S_S2 is approximately also applied to the resistor R3 in the limit signal unit L_U.
  • the resistor R3 is thus arranged electrically parallel to the resistor Rl.
  • the limit signal UL is thus assigned the voltage across the resistor R2.
  • the switching element Tl is operated in normal operation and the resistors Rl, R2 and R3 of the limit signal unit LU, and the resistors R4, R5, RS of the sensor signal unit S_U are predetermined such that the voltage value of the sensor signal U_IS at the inverting input of the comparator COMP is smaller than the voltage value of the limit signal UL at the non-inverting input, the comparator COMP blocks its open-collector output and the supply voltage potential VCC of the further switching signal S S2 remains approximately at the switching terminal IN of
  • Value of the given load current limit is.
  • the load current IL representing, the value of the sensor current IS through the shunt resistor RS increases in the sensor signal unit SU and thus the voltage value of the sensor signal U_IS.
  • the voltage value of the limit signal UL at the non-inverting input of the comparator COMP is exceeded by the voltage value of the sensor signal U IS at the inverting input, whereby the comparator COMP turns on its open-collector output.
  • the switching signal S Sl is put through the switching of the open-collector output to ground potential GND, so that in the limit signal unit L_U, the resistor R3 is arranged electrically parallel to the resistor R2 to ground GND, whereby the limit signal UL, the voltage across the e- lektrisch associated in parallel with resistors R2 and R3.
  • the voltage value of the limit signal UL is thus smaller in overload operation than in normal operation of the switching element Tl.
  • the switching terminal IN of the switching element Tl is set to ground potential GND by means of the switching signal S_S1 and thus the switching element Tl is switched off.
  • the load current IL through the switching element Tl, as well as the load current IL representing sensor current IS drops to 0 A.
  • the shunt resistor RS flows with switched-off switching element Tl only the first current II, whereby the voltage value of the sensor signal U IS is smaller than immediately before switching off of the switching element Tl in overload operation.
  • the voltage value of the limit signal UL by means of the switching signal S Sl is smaller and the resistors R4, R5, RS are dimensioned appropriately, the voltage value of the sensor signal U_IS at the comparator COMP remains above that of the limit signal UL, whereby the switching signal S_S1 means of Open collector output of the comparator COMP is still at ground potential GND and the switching element Tl remains off. Also by means of the further switching signal S S2, the switching element Tl can not be turned on again.
  • the control unit CTRL can reset the reset element T RESET in the sensor signal unit SU turn on and thus set the sensor signal U_IS at ground potential GND, whereby the input side of the comparator COMP the voltage value of the limit signal UL exceeds that of the sensor signal U_IS.
  • the comparator COMP blocks its open collector output and the still applied supply voltage VCC of the further switching signal S_S2 turn on the switching element Tl again.
  • the switching element Tl can be turned off by means of the control unit CTRL, whereby the further switching signal S_S2 and the switching signal S_S1 are set to ground potential GND.
  • the limit signal unit L U of the resistor R3 is electrically connected in parallel to the resistor R2 to ground GND, whereby the limit signal UL, the voltage across the electrical parallel-connected resistors R2 and R3 is assigned.
  • the voltage value of the sensor signal U_IS at the inverting input of the comparator COMP is thereby greater than that of the limit signal UL at the noninverting input, whereby the open collector output of the comparator COMP is turned on and the switching signal S_S1 is switched through to ground GND.
  • the switching element Tl can be switched on again in the non-overload operation, wherein, in addition to the further switching signal S_S2, the reset switching signal S_RESET is also switched to the supply voltage potential VCC for the predetermined period of time.
  • the reset switching element T_RESET is turned on and by means of this the sensor signal U_IS is set to ground potential GND.
  • the lying at ground potential GND sensor signal U IS of the open-collector output of the comparator COMP is disabled, whereby the lying on the supply voltage potential VCC further switching signal S_S2 released and the switching element Tl is turned on.
  • the reset switching element T RESET is switched off.
  • the sensor signal unit SU comprises a capacitor Cl. This is assigned to the first node VK1 and the ground GND.
  • the capacitor Cl forms a low-pass filter with the resistors R4 and R5, whereby, on the one hand, voltage and / or current peaks in the supply voltage VCC and / or in the sensor current IS are diverted to ground GND.
  • the sensor signal U_IS is delayed given by the low-pass filter, whereby short-term current changes of the load current IL, which are in the range specified by the predetermined dimensioning of the resistors R4, R5 duration, such as current changes in the range 2 ms to 5 ms, not to shutdown of the switching element Tl lead.
  • the capacitor Cl is discharged by means of the through-connected reset switching element T RESET. After expiration of the predetermined period of time, the
  • Reset switching element T_RESET switched off by means of reset signal S_RESET and the sensor signal U_IS is delayed by the low-pass filter formed by capacitor Cl.
  • load currents IL which are greater than the predetermined load current limit, such as typical inrush currents in lighting means in the motor vehicle, to no unwanted shutdown of the switching element Tl.
  • load currents IL can also be conducted above the predetermined load current limit by means of the switching element T1.

Landscapes

  • Electronic Switches (AREA)

Abstract

The invention relates to a switching system comprising a switch element (T1) associated with a load (RL) and having a control device (C_U), a sensor signal unit (S_U) designed to determine a sensor signal (U_IS) representative of a load current (IL) through the load (RL). The control device (C_U) further comprises a limit signal unit (L_U) designed to provide a limit signal (UL) representative of a prescribed load current limit of the load current (IL). The control device (C_U) further comprises a comparator (COMP) designed to compare the sensor signal (U_IS) present at the input side with the limit signal (UL) present at the input side, and to generate as a function thereof an output-side switch signal (S_S1), such that when a value of the limit signal (UL) is reached by the sensor signal (U_IS), the switching element (T1) is switched off.

Description

Schaltsystem switching system
In heutigen Kraftfahrzeugen werden zum Schalten von ohmschen und induktiven Lasten bevorzugt High-Side- und/oder Low-Side- Schalter, so z.B. zum Schalten von Beleuchtungsmitteln oder Luftventile zur Niveauregelung, verwendet. Dabei ist eine dem High-Side-Schalter zugeordnete Last typischerweise mit der Masse des Kraftfahrzeugs verbunden. Diese Anordnung des High- Side-Schalters mit der massebezogenen Last benötigt eine Steuerspannung, die höher ist als eine die Last versorgende Eingangsspannung. Für die Ansteuerung derartiger Schaltelemente werden beispielsweise Smart-High-Side-Schalter verwendet, die die benötigte Steuerspannung intern erzeugen.In today's motor vehicles, for switching ohmic and inductive loads, preference is given to high-side and / or low-side switches, e.g. for switching lighting or air valves for level control used. In this case, a load assigned to the high-side switch is typically connected to the mass of the motor vehicle. This arrangement of the high-side switch with the ground-based load requires a control voltage which is higher than an input voltage supplying the load. For the control of such switching elements, for example, smart high-side switches are used, which generate the required control voltage internally.
Eine dem Low-Side-Schalter zugeordnete Last ist typischerweise mit der Eingangsspannung verbunden. Der Low-Side-Schalter ist typischerweise massebezogen angeordnet, wodurch eine besondere Ansteuerung wie im Falle des High-Side-Schalters nicht erforderlich ist. Der Low-Side-Schalter kann aber, wie auch der High-Side-Schalter als Smart-Schaltelement ausgeführt sein.A load associated with the low-side switch is typically connected to the input voltage. The low-side switch is typically ground-referenced, whereby a special control as in the case of the high-side switch is not required. The low-side switch can be designed as well as the high-side switch as a smart switching element.
Smart-High-Side- und/oder Smart-Low-Side-Schalter sind kurzschlussgeschützte Schaltelemente, die durch eine thermische Überwachung bei Überlaststrom abgeschaltet werden. Diese thermische Abschaltung erfolgt typischerweise weit oberhalb des normalen Arbeitsbereiches des Schaltelements, d.h. der Strom durch das Schaltelement muss entsprechend hoch sein, damit die thermische Abschaltung reagiert und die Last abschaltet. Deshalb muss der entsprechende Smart-High-Side- Schalter oder Smart-Low-Side-Schalter, die dazugehörige Schaltungsanordnung, die Stecker, etc. für diesen hohen Überlaststrom ausgelegt sein, damit keine Schädigung der Bauelemente und der Schaltungsanordnung auftreten kann. Die Aufgabe, die der Erfindung zugrunde liegt, ist es, ein Schaltsystem mit einem Schaltelement zu schaffen, das einfach und möglichst schnell im Überlastbetrieb das Schaltelement abschaltet .Smart high-side and / or smart low-side switches are short-circuit protected switching elements that are switched off by thermal overload monitoring. This thermal shutdown is typically well above the normal operating range of the switching element, ie the current through the switching element must be correspondingly high, so that the thermal shutdown responds and shuts off the load. Therefore, the corresponding smart high-side switch or smart low-side switch, the associated circuitry, the plug, etc. must be designed for this high overload current, so that no damage to the components and the circuit can occur. The object underlying the invention is to provide a switching system with a switching element that switches off the switching element easily and as quickly as possible in overload operation.
Die Aufgabe wird gelöst durch die Merkmale des unabhängigen Patentanspruchs. Vorteilhafte Ausgestaltungen der Erfindung sind in den Unteransprüchen gekennzeichnet.The object is solved by the features of the independent claim. Advantageous embodiments of the invention are characterized in the subclaims.
Die Erfindung zeichnet sich aus durch ein Schaltsystem mit einem Schaltelement, das einer Last zugeordnet ist, und mit einer Ansteuervorrichtung aufweisend eine Sensorsignaleinheit, die dazu ausgebildet ist, ein Sensorsignal, welches repräsentativ ist für einen Laststrom durch die Last, zu ermit- teln . Ferner weist die Ansteuervorrichtung eine Grenzsignaleinheit auf, die dazu ausgebildet ist, ein Grenzsignal, welches repräsentativ ist für eine vorgegebene Laststromgrenze des Laststroms, vorzugeben. Des Weiteren weist die Ansteuervorrichtung einen Komparator auf, der dazu ausgebildet ist, das eingangsseitig anliegende Sensorsignal mit dem eingangs- seitig anliegenden Grenzsignal zu vergleichen und davon abhängig ausgangsseitig ein Schaltsignal vorzugeben und zwar derart, dass beim Erreichen eines Werts des Grenzsignals durch das Sensorsignal das Schaltelement abgeschaltet wird. Die Sensorsignaleinheit ist besonders geeignet, ein Laststrom repräsentierendes Sensorsignal zu ermitteln. Mittels der Grenzsignaleinheit kann besonders geeignet eine Laststromgrenze für den Laststrom mittels des Grenzsignals vorgegeben werden. Der Komparator ist besonders geeignet das Sensorsig- nal und das Grenzsignal miteinander zu vergleichen und ausgangsseitig das Schaltsignal vorzugeben.The invention is characterized by a switching system with a switching element, which is assigned to a load, and with a drive device having a sensor signal unit, which is designed to determine a sensor signal, which is representative of a load current through the load. Furthermore, the drive device has a limit signal unit which is designed to specify a limit signal, which is representative of a predetermined load current limit of the load current. Furthermore, the drive device has a comparator which is designed to compare the sensor signal applied on the input side with the limit signal applied on the input side and to specify a switching signal dependent on the output side in such a way that when a value of the limit signal is reached by the sensor signal the switching element is switched off. The sensor signal unit is particularly suitable for determining a sensor signal representing a load current. By means of the limit signal unit, a load current limit for the load current can be specified in a particularly suitable manner by means of the limit signal. The comparator is particularly suitable to compare the sensor signal and the limit signal with each other and to specify the switching signal on the output side.
Erreicht das Sensorsignal den Wert des Grenzsignals wird mittels des Schaltsignals das Schaltelement abgeschaltet, so dass das Schaltelement nicht unnötig lange mit einem Strom größer oder gleich dem Wert der Laststromgrenze betrieben wird . Gemäß einer vorteilhaften Ausgestaltung ist der Komparator als Operationsverstärker ausgebildet, wobei dem Operationsverstärker eingangsseitig das Sensorsignal und das Grenzsig- nal und ausgangsseitig das Schaltsignal zugeordnet ist. Durch den Operationsverstärker kann der Komparator besonders einfach, kostengünstig und zuverlässig ausgebildet werden.If the sensor signal reaches the value of the limit signal, the switching element is switched off by means of the switching signal, so that the switching element is not operated unnecessarily long with a current greater than or equal to the value of the load current limit. According to an advantageous embodiment of the comparator is designed as an operational amplifier, wherein the operational amplifier on the input side, the sensor signal and the Grenzsig- signal and the output side, the switching signal is assigned. Due to the operational amplifier, the comparator can be formed particularly simple, inexpensive and reliable.
Gemäß einer weiteren vorteilhaften Ausgestaltung ist der Aus- gang des Komparators als Open-Collector-Ausgang ausgebildet. Dadurch kann besonders einfach das dem Ausgang zugeordnete Schaltsignal vorgegeben werden.According to a further advantageous embodiment, the output of the comparator is designed as an open-collector output. As a result, it is particularly easy to specify the switching signal assigned to the output.
Gemäß einer weiteren vorteilhaften Ausgestaltung ist die Sen- sorsignaleinheit als ein Spannungsteiler ausgebildet und dem Schaltelement zugeordnet und ermittelt abhängig von einem Strom durch das Schaltelement das Sensorsignal. Durch den Spannungsteiler kann besonders einfach und kostengünstig das Sensorsignal ermittelt werden.According to a further advantageous refinement, the sensor signal unit is designed as a voltage divider and assigned to the switching element and determines the sensor signal as a function of a current through the switching element. The voltage divider makes it possible to determine the sensor signal in a particularly simple and cost-effective manner.
Gemäß einer weiteren vorteilhaften Ausgestaltung umfasst die Sensorsignaleinheit ein Resetschaltelement, das dazu ausgebildet ist, abhängig vom einem dem Resetschaltelement zugeordneten vorgegeben Resetsignal, das ausgeschaltete Schalt- element freizugeben. Mittels des Resetschaltelements kann besonders einfach das Schaltelement derart freigegeben werden, dass das Schaltelement wieder eingeschaltet werden kann.According to a further advantageous embodiment, the sensor signal unit comprises a reset switching element, which is designed to release the switched-off switching element as a function of the reset signal assigned to the reset switching element. By means of the reset switching element, the switching element can be released in a particularly simple manner such that the switching element can be switched on again.
Gemäß einer weiteren vorteilhaften Ausgestaltung umfasst die Sensorsignaleinheit einen Kondensator, der mit einem oder mehreren dem Spannungsteiler zugeordneten Widerständen als Tiefpass angeordnet und ausgebildet ist, und zwar derart, dass das Sensorsignal tiefpassgefiltert wird. Mittels des o- der der Widerstände und des Kondensators kann der Tiefpass besonders einfach ausgebildet werden. Mit dem Tiefpass lassen sich hochfrequente Signalkomponenten des Sensorsignals besonders einfach herausfiltern. Des Weiteren wird durch die Verwendung des Tiefpasses das Sensorsignal U_IS verzögert vorgegeben, wodurch kurzzeitige Stromänderun- gen des Laststroms IL, die im Bereich einer durch eine vorgegebene Dimensionierung des Tiefpasses vorgegebenen Zeitdauer liegen, nicht zum Abschalten des Schaltelements führen.According to a further advantageous embodiment, the sensor signal unit comprises a capacitor which is arranged and configured as a low-pass filter with one or more resistors associated with the voltage divider, in such a way that the sensor signal is low-pass filtered. By means of the o- of the resistors and the capacitor, the low pass can be made particularly simple. The low-pass filter makes it particularly easy to filter out high-frequency signal components of the sensor signal. Furthermore, the sensor signal U_IS is delayed given by the use of the low-pass filter, whereby short-term current changes of the load current IL, which are in the range of a predetermined by a predetermined dimensioning of the low-pass duration, do not lead to shutdown of the switching element.
Gemäß einer weiteren vorteilhaften Ausgestaltung umfasst die Grenzsignaleinheit einen Spannungsteiler. Mit diesem lässt sich die Grenzsignaleinheit besonders einfach und zuverlässig realisieren .According to a further advantageous embodiment, the limit signal unit comprises a voltage divider. With this, the limit signal unit can be implemented particularly easily and reliably.
Gemäß einer weiteren vorteilhaften Ausgestaltung ist das Grenzsignal abhängig von dem am Komparator ausgangsseitig anliegenden Schaltsignal. Dadurch ist das Grenzsignal auch abhängig von dem gerade gültigen Zustand des Schaltsignals, wodurch besonders geeignet das Grenzsignal angepasst werden kann .According to a further advantageous embodiment, the limit signal is dependent on the output signal applied to the comparator on the comparator. As a result, the limit signal is also dependent on the currently valid state of the switching signal, whereby the limit signal can be adapted particularly suitable.
Durch die Anpassung des Grenzsignals kann dieses derart vorgegeben werden, dass mittels des Schaltsignals das Schaltelement nach einem Überlastbetrieb solange abgeschaltet bleibt, bis mittels des Resetsignals das Schaltelement wieder freige- geben wird und wieder eingeschaltet werden kann.By adjusting the limit signal, this can be specified such that by means of the switching signal, the switching element remains switched off after an overload operation until the switching element is released again by means of the reset signal and can be switched on again.
Gemäß einer weiteren vorteilhaften Ausgestaltung ist das Schaltelement als Smart-High-Side-Schalter und/oder als Smart-Low-Side-Schalter ausgebildet und das Sensorsignal ab- hängig von einem dem Smart-High-Side- und/oder dem Smart-Low- Side-Schalter zugeordneten Sensorstrom, der repräsentativ ist für einen Strom durch den Smart-High-Side- und/oder den Smart-Low-Side-Schalter. Dadurch kann das Sensorsignal besonders einfach dem Sensorstrom des Smart-High-Side- und/oder Smart-Low-Side-Schalters zugeordnet werden. Der Sensorstrom kann bei dem Smart-High-Side- oder dem Smart- Low-Side-Schalter als ein vom Strom durch den Schalter abgeleiteter Strom ausgebildet sein. Der Sensorstrom kann aber auch als der Strom durch den Schalter, d.h. der Laststrom, ausgebildet sein.According to a further advantageous embodiment, the switching element is designed as a smart high-side switch and / or as a smart low-side switch, and the sensor signal is dependent on one of the smart high-side and / or the smart low - Side switch associated sensor current, which is representative of a current through the smart high-side and / or the smart low-side switch. As a result, the sensor signal can be particularly easily associated with the sensor current of the smart high-side and / or smart low-side switch. The sensor current may be formed in the smart high side or the smart low side switch as a current derived from the current through the switch. However, the sensor current can also be embodied as the current through the switch, ie the load current.
Gemäß einer weiteren vorteilhaften Ausgestaltung ist das Schaltelement als Feldeffekt- und/oder als Bipolartransistor ausgebildet und das Sensorsignal abhängig von dem Strom durch das entsprechende Schaltelement. Dadurch lässt sich besonders einfach der Strom durch das entsprechende Schaltelement als Sensorsignal darstellen.According to a further advantageous embodiment, the switching element is designed as a field effect and / or as a bipolar transistor and the sensor signal depends on the current through the corresponding switching element. This makes it particularly easy to represent the current through the corresponding switching element as a sensor signal.
Ausführungsbeispiele der Erfindung sind im Folgenden anhand der schematischen Zeichnungen näher erläutert. Es zeigen:Embodiments of the invention are explained in more detail below with reference to the schematic drawings. Show it:
Figur 1 eine Schaltungsanordnung eines Schaltsystems mit AnsteuervorrichtungFigure 1 shows a circuit arrangement of a switching system with drive device
Figur 2 eine weitere Schaltungsanordnung eines Schaltsystems mit AnsteuervorrichtungFigure 2 shows another circuit arrangement of a switching system with drive device
Elemente gleicher Konstruktion oder Funktion sind figurenübergreifend mit dem gleichen Bezugszeichen gekennzeichnet.Elements of the same construction or function are identified across the figures by the same reference numeral.
Eine Schaltungsanordnung eines Schaltsystems mit einem Schaltelement Tl und einer Ansteuervorrichtung C U ist in Figur 1 dargestellt. Es zeigt das als Smart-Low-Side-Schalter ausgebildete Schaltelement Tl, dem eine Last RL zugeordnet ist. Der Last RL ist zusätzlich eine Eingangsspannung V IN zugeordnet, die beispielsweise einer Versorgungsspannung eines Bordnetzes eines Kraftfahrzeugs zugeordnet werden kann. Das Schaltelement Tl umfasst neben einem Drainanschluss D und einem Sourceanschluss S einen Schaltanschluss IN, mittels dessen das Schaltelement Tl ein- oder ausgeschaltet werden kann . Die Ansteuervorrichtung C U umfasst eine Sensorsignaleinheit S U, die zwischen dem Schaltelement Tl und der Masse GND angeordnet ist. Der Sensorsignaleinheit S_U wird ein Laststrom IL, der bei eingeschaltetem Schaltelement Tl durch die Last RL und das Schaltelement Tl fließt, zugeordnet. Dem Laststrom IL kann der Sensorstrom IS zugeordnet werden. Abhängig von diesem generiert die Sensorsignaleinheit S_U ein Sensorsignal U_IS, das repräsentativ ist für den Laststrom IL. Das Sensorsignal kann als Strom oder Spannung ausgebildet sein. Ferner hat die Sensorsignaleinheit S_U einen Resetsignaleingang für ein Resetsignal S_RESET, mittels dessen das Sensorsignal U_IS beispielsweise auf Massepotential GND gelegt werden kann.A circuit arrangement of a switching system with a switching element Tl and a drive device CU is shown in FIG. It shows the designed as a smart low-side switch switching element Tl, which is associated with a load RL. The load RL is additionally assigned an input voltage V IN, which can be assigned, for example, to a supply voltage of a vehicle electrical system of a motor vehicle. The switching element Tl comprises, in addition to a drain connection D and a source connection S, a switching connection IN, by means of which the switching element Tl can be switched on or off. The drive device CU comprises a sensor signal unit SU, which is arranged between the switching element Tl and the ground GND. The sensor signal unit S_U is assigned a load current IL, which flows through the load RL and the switching element Tl when the switching element T1 is switched on. The load current IL, the sensor current IS can be assigned. Depending on this, the sensor signal unit S_U generates a sensor signal U_IS, which is representative of the load current IL. The sensor signal can be designed as current or voltage. Furthermore, the sensor signal unit S_U has a reset signal input for a reset signal S_RESET, by means of which the sensor signal U_IS can be set to ground potential GND, for example.
Des Weiteren umfasst die Ansteuervorrichtung C_U des Schalt- elements Tl eine Grenzsignaleinheit L_U . Mittels dieser wird ein Grenzsignal UL ermittelt, das repräsentativ ist für eine vorgegebene Laststromgrenze des Laststroms IL. Das Grenzsignal UL kann als Strom oder Spannung ausgebildet sein und ist bevorzugt derart vorgegeben, dass die durch das Grenzsignal UL repräsentierte Laststromgrenze kleiner ist als eine durch eine thermische Abschaltung vorgegebene Stromgrenze des als Smart-Low-Side-Schalters ausgebildeten Schaltelements Tl.Furthermore, the drive device C_U of the switching element Tl comprises a limit signal unit L_U. By means of this a limit signal UL is determined, which is representative of a predetermined load current limit of the load current IL. The limit signal UL can be embodied as a current or voltage and is preferably predetermined such that the load current limit represented by the limit signal UL is smaller than a current limit of the switching element Tl designed as a smart low-side switch.
Ferner umfasst die Ansteuervorrichtung C_U einen Komparator COMP dem eingangsseitig das Sensorsignal U_IS der Sensorsignaleinheit S U und das Grenzsignal UL der Grenzsignaleinheit L U zugeordnet sind. Der Komparator COMP ist dazu ausgebildet, die eingangsseitig anliegenden Signale miteinander zu vergleichen und abhängig von dem Vergleich ausgangsseitig ein Schaltsignal S Sl vorzugeben. Das Schaltsignal S Sl ist dem Schaltanschluss IN des Schaltelements Tl zugeordnet.Furthermore, the drive device C_U comprises a comparator COMP on the input side of which the sensor signal U_IS of the sensor signal unit S U and the limit signal UL of the limit signal unit L U are assigned. The comparator COMP is designed to compare the signals present on the input side with one another and, depending on the comparison, to predetermine a switching signal S S1 on the output side. The switching signal S S1 is assigned to the switching terminal IN of the switching element T1.
Neben der Ansteuervorrichtung C U ist in Figur 1 eine Steuereinheit CTRL dargestellt, die beispielsweise als ein Mikro- Controller ausgebildet ist und die Ansteuervorrichtung C_U ansteuert. Der Steuereinheit CTRL ist ausgangsseitig ein weiteres Schaltsignal S S2 zugeordnet, welches über einen Vorwi- derstand R6 mit dem Schaltsignal S Sl verbunden ist, wodurch mittels des weiteren Schaltsignals S_S2 das Schaltelement Tl ein- oder ausgeschaltet werden kann. Ferner ist der Steuereinheit CTRL eingangsseitig das Schaltsignal S_S1 des Kompa- rators COMP zugeordnet, um den aktuellen Status der Ansteuervorrichtung C U und somit den Status des Schaltelements Tl zu erfassen. Des Weiteren ist die Steuereinheit CTRL ausgangs- seitig mittels des Resetsignals S RESET mit der Sensorsignaleinheit S U verbunden.In addition to the drive device CU, a control unit CTRL is shown in FIG. 1, which is designed, for example, as a microcontroller and controls the drive device C_U. On the output side, the control unit CTRL is assigned a further switching signal S S2, which is output via a preceding switch signal S S2. the resistor R6 is connected to the switching signal S Sl, whereby the switching element Tl can be switched on or off by means of the further switching signal S_S2. Furthermore, the control unit CTRL is assigned on the input side the switching signal S_S1 of the comparator COMP in order to detect the current status of the drive device CU and thus the status of the switching element Tl. Furthermore, the control unit CTRL is connected on the output side to the sensor signal unit SU by means of the reset signal S RESET.
Im Normalbetrieb des Schaltelements Tl, der dadurch gekennzeichnet ist, dass ein Laststrom IL durch das Schaltelement Tl fließt, der kleiner ist als die vorgegebene Laststromgrenze, wird das Schaltelement Tl mittels des weiteren Schaltsig- nals S_S2 von der Steuereinheit CTRL angesteuert. Im Normalbetrieb ist der Wert des mittels der Sensorsignaleinheit S_U ermittelten Sensorsignals U_IS kleiner als der Wert des Grenzsignals UL, wodurch das ausgangsseitig vom Komparator COMP vorgegebene Schaltsignal S_S1 das weitere Schaltsignal S_S2 freigibt. Mittels diesem kann die Steuereinheit CTRL das Schaltelement Tl ausschalten und bei gleichzeitigem Einschalten des Resettransistors T_RESET mittels des Resetsignals S RESET für eine vorgegebene Zeitdauer das Schaltelement Tl auch wieder einschalten.In normal operation of the switching element Tl, which is characterized in that a load current IL flows through the switching element Tl, which is smaller than the predetermined load current limit, the switching element Tl by means of the further switching signal S_S2 is controlled by the control unit CTRL. In normal operation, the value of the sensor signal U_IS determined by means of the sensor signal unit S_U is smaller than the value of the limit signal UL, whereby the switching signal S_S1 specified on the output side by the comparator COMP releases the further switching signal S_S2. By means of this, the control unit CTRL turn off the switching element Tl and turn on the switching element Tl again with simultaneous switching on of the reset transistor T_RESET by means of the reset signal S RESET for a predetermined period of time.
Ein Überlastbetrieb des Schaltelements Tl ist gekennzeichnet durch einen Laststrom IL, dessen Wert größer ist als der der Laststromgrenze. Das mittels der Sensorsignaleinheit S_U ermittelte Sensorsignal U_IS repräsentiert den aktuellen Last- ström IL. Somit ist der Wert des Sensorsignals U IS in demAn overload operation of the switching element Tl is characterized by a load current IL whose value is greater than that of the load current limit. The sensor signal U_IS determined by means of the sensor signal unit S_U represents the current load flow IL. Thus, the value of the sensor signal U IS in the
Überlastbetrieb des Schaltelements Tl größer oder gleich dem Wert des Grenzsignals UL. Dem eingangsseitigen Vergleich des Sensorsignals U IS und des Grenzsignals UL entsprechend, wird ausgangsseitig am Komparator COMP das Schaltsignal S Sl der- art vorgegeben, dass das weitere Schaltsignal S_S2 nicht weiter bezüglich des Schaltanschlusses IN freigegeben ist, sondern durch das Schaltsignal S Sl vorgegeben wird und zwar derart, dass das Schaltelement Tl abgeschaltet wird. Dabei ist die Ansteuervorrichtung C_U bevorzugt derart ausgebildet, dass das Schaltelement Tl solange abgeschaltet bleibt, bis die Steuereinheit CTRL mittels des Resetsignals S_RESET das weitere Schaltsignal S_S2 freigibt und das Schaltelement Tl wieder eingeschaltet werden kann.Overload operation of the switching element Tl greater than or equal to the value of the limit signal UL. On the input side comparison of the sensor signal U IS and the limit signal UL, the switching signal S S1 is preset at the comparator COMP such that the further switching signal S_S2 is not further enabled with respect to the switching terminal IN, but is predetermined by the switching signal S S1 and though such that the switching element Tl is turned off. The control device C_U is preferably designed such that the switching element Tl remains switched off until the control unit CTRL releases the further switching signal S_S2 by means of the reset signal S_RESET and the switching element Tl can be switched on again.
In einem weiteren Ausführungsbeispiel (Figur 2) ist das Schaltelement Tl als ein Smart-High-Side-Schalter ausgebil- det . Dieses umfasst den Schaltanschluss IN mittels dessen das Schaltelement Tl ein- oder abgeschaltet werden kann. Des Weiteren umfasst das Schaltelement Tl einen Lastausgang OUT, der der massebezogenen Last RL zugeordnet ist und über dem der volle Laststrom IL fließt, wenn das Schaltelement Tl einge- schaltet ist. Ferner umfasst das Schaltelement Tl einenIn a further exemplary embodiment (FIG. 2), the switching element T1 is designed as a smart high-side switch. This includes the switching terminal IN by means of which the switching element Tl can be switched on or off. Furthermore, the switching element Tl comprises a load output OUT, which is assigned to the mass-based load RL and over which the full load current IL flows when the switching element Tl is turned on. Furthermore, the switching element Tl comprises a
Stromsensierungsausgang I_S, mittels dessen ein den Laststrom IL repräsentierender Sensorstrom IS der Ansteuervorrichtung C_U zugeführt wird. Der Sensorstrom IS ist von dem Strom durch das Schaltelement Tl abgeleitet und ist typischerweise kleiner, so z.B. um einen Faktor 5000, als der Strom durch das Schaltelement Tl. Das Schaltelement Tl wird über die Eingangsspannung V_IN gespeist. Die Sensorsignaleinheit S_U in der Ansteuervorrichtung C U umfasst einen Spannungsteiler R4 , R5, RS, wobei dem Widerstand R4 eine Versorgungsspannung VCC zugeordnet ist, so z.B. 5 V. Über einen ersten Verknüpfungspunkt VKl wird dem Spannungsteiler R4, R5, RS der Sensorstrom IS zugeführt. Über einen zweiten Verknüpfungspunkt VK2 wird das Sensorsignal U_IS abgegriffen. Des Weiteren umfasst die Sensorsignaleinheit S_U ein Resetschaltelement T_RESET, das dem Sensorsignal U_IS zugeordnet ist und mittels dessen dasCurrent sensing output I_S, by means of which a load current IL representing sensor current IS of the drive device C_U is supplied. The sensor current IS is derived from the current through the switching element Tl and is typically smaller, e.g. by a factor of 5000, as the current through the switching element Tl. The switching element Tl is fed via the input voltage V_IN. The sensor signal unit S_U in the drive device C U comprises a voltage divider R4, R5, RS, wherein the resistor R4 is assigned a supply voltage VCC, e.g. 5 V. The sensor current IS is fed to the voltage divider R4, R5, RS via a first connection point VK1. The sensor signal U_IS is tapped off via a second connection point VK2. Furthermore, the sensor signal unit S_U comprises a reset switching element T_RESET which is assigned to the sensor signal U_IS and by means of which the
Sensorsignal U IS abhängig vom Resetsignal S RESET auf Massepotential GND gelegt werden kann. Ein der Versorgungsspannung VCC zugeordneter erster Strom Il fließt durch die Widerstände R4, R5 und RS. Da die Widerstände R4 , R5 und RS vorgegeben sind und sich deren Widerstandswerte während des Betriebs der Ansteuervorrichtung C_U nicht ändern, ist der erste Strom Il entsprechend der vorgegebenen Dimensionierung der Widerstände R4 , R5 und RS fest vorgegeben. Über den ersten Verknüpfungspunkt VKl, der dem als Shuntwiderstand ausgebildeten Widerstand RS zugeordnet ist, wird zusätzlich der Sensorstrom IS eingespeist, so dass durch den Shuntwiderstand RS ein resul- tierender Strom aus der Summe des ersten Stroms Il und des Sensorstroms IS fließt, wenn ein Laststrom IL fließt. Der Spannungsabfall über dem Shuntwiderstand RS ist somit abhängig von dem Sensorstrom IS. Somit ist auch das Sensorsignal U IS, das als Spannungssignal über den Widerständen R5 und RS abgegriffen wird, abhängig von dem Sensorstrom IS. Da derSensor signal U IS can be set depending on the reset signal S RESET to ground potential GND. A first current Il associated with the supply voltage VCC flows through the resistors R4, R5 and RS. Since the resistors R4, R5 and RS are predetermined and their resistance values do not change during the operation of the drive device C_U, the first current Il is corresponding to the predetermined dimensioning of the resistors Fixed R4, R5 and RS. The sensor current IS is additionally fed via the first connection point VK1, which is assigned to the resistor RS designed as a shunt resistor, so that a resulting current flows through the shunt resistor RS from the sum of the first current Il and the sensor current IS, if a load current IL is flowing. The voltage drop across the shunt resistor RS is thus dependent on the sensor current IS. Thus, the sensor signal U IS, which is tapped as a voltage signal across the resistors R5 and RS, depending on the sensor current IS. Since the
Sensorstrom IS repräsentativ ist für den Laststrom IL durch das Schaltelement Tl, ist auch das Sensorsignal U_IS repräsentativ für den Laststrom IL.Sensor current IS is representative of the load current IL through the switching element Tl, the sensor signal U_IS is representative of the load current IL.
Die Grenzsignaleinheit L_U umfasst einen Spannungsteiler mit den Widerständen Rl, R2 , R3. Mittels der vorgegebenen Dimensionierung der Widerstände Rl, R2, R3 wird das Grenzsignal UL als Spannungssignal vorgegeben. Der Widerstand Rl ist der Versorgungsspannung VCC zugeordnet. Die Widerstände R2 und R3 sind dem Widerstand Rl zugeordnet und der Widerstand R2 ist mit der Masse GND verbunden. Über einen dritten Verknüpfungspunkt VK3 wird das Grenzsignal UL abgegriffen. Das Grenzsignal UL ist somit von der Dimensionierung der Widerstände Rl, R2, R3 abhängig. Ferner ist das Grenzsignal UL auch abhängig von dem jeweiligen Wert des Schaltsignals S_S1, dass dem Widerstand R3 zugeordnet ist.The limit signal unit L_U comprises a voltage divider with the resistors Rl, R2, R3. By means of the predetermined dimensioning of the resistors Rl, R2, R3, the limit signal UL is specified as a voltage signal. The resistor Rl is assigned to the supply voltage VCC. The resistors R2 and R3 are assigned to the resistor R1 and the resistor R2 is connected to the ground GND. About a third node VK3 the limit signal UL is tapped. The limit signal UL is thus dependent on the dimensioning of the resistors Rl, R2, R3. Furthermore, the limit signal UL is also dependent on the respective value of the switching signal S_S1 associated with the resistor R3.
Der Komparator COMP ist als Spannungskomparator mit einem O- perationsverstärker OPV mit einem invertierten und einem nicht-invertierten Eingang ausgebildet. Dem invertierenden Eingang des Operationsverstärkers OPV ist das Sensorsignal U_IS zugeordnet und dem nicht-invertierenden Eingang das Grenzsignal UL. Der Ausgang des Komparators COMP ist typischerweise als Open-Collector-Ausgang ausgebildet und das Schaltsignal S Sl zugeordnet. Auch in Figur 2 wird die Ansteuervorrichtung C U, wie bereits in Figur 1 dargestellt, mittels der Steuereinheit CTRL angesteuert .The comparator COMP is designed as a voltage comparator with an operating amplifier OPV with an inverted and a non-inverted input. The inverting input of the operational amplifier OPV is assigned the sensor signal U_IS and the non-inverting input the limit signal UL. The output of the comparator COMP is typically formed as an open-collector output and assigned the switching signal S Sl. Also in Figure 2, the drive device CU, as already shown in Figure 1, controlled by the control unit CTRL.
Für die folgende Darstellung wird angenommen, dass die Steuereinheit CTRL das weitere Schaltsignal S S2 mit einer Spannung in Höhe der Versorgungsspannung VCC vorgibt und somit das Schaltelement Tl eingeschaltet ist.For the following illustration, it is assumed that the control unit CTRL prescribes the further switching signal S S2 with a voltage in the amount of the supply voltage VCC, and thus the switching element T 1 is switched on.
Weiter wird der Normalbetrieb angenommen, d.h. der Wert des durch das Schaltelement Tl fließenden Laststroms IL ist kleiner als der Wert der vorgegebenen Laststromgrenze.Further, normal operation is assumed, i. the value of the load current IL flowing through the switching element Tl is smaller than the value of the predetermined load current limit.
Da das Schaltsignal S_S1 mittels des Vorwiderstandes R6 mit dem weiteren Schaltsignal S_S2 verbunden ist, liegt bei eingeschaltetem Schaltsignal S_S1 das Versorgungsspannungpotential VCC des weiteren Schaltsignals S_S2 näherungsweise auch am Widerstand R3 in der Grenzsignaleinheit L_U an. Der Widerstand R3 ist somit elektrisch parallel zum Widerstand Rl an- geordnet. Dem Grenzsignal UL wird somit die Spannung über dem Widerstand R2 zugeordnet. Da das Schaltelement Tl im Normalbetrieb betrieben wird und die Widerstände Rl, R2 und R3 der Grenzsignaleinheit L U, sowie die Widerstände R4 , R5, RS der Sensorsignaleinheit S_U derart vorgegeben sind, dass der Spannungswert des Sensorsignals U_IS am invertierenden Eingang des Komparators COMP kleiner ist als der Spannungswert des Grenzsignals UL am nicht-invertierenden Eingang, sperrt der Komparator COMP seinen Open-Collector-Ausgang und das Versorgungsspannungpotential VCC des weiteren Schaltsignals S S2 bleibt näherungsweise weiter am Schaltanschluss IN desSince the switching signal S_S1 is connected to the further switching signal S_S2 by means of the series resistor R6, when the switching signal S_S1 is switched on, the supply voltage potential VCC of the further switching signal S_S2 is approximately also applied to the resistor R3 in the limit signal unit L_U. The resistor R3 is thus arranged electrically parallel to the resistor Rl. The limit signal UL is thus assigned the voltage across the resistor R2. Since the switching element Tl is operated in normal operation and the resistors Rl, R2 and R3 of the limit signal unit LU, and the resistors R4, R5, RS of the sensor signal unit S_U are predetermined such that the voltage value of the sensor signal U_IS at the inverting input of the comparator COMP is smaller than the voltage value of the limit signal UL at the non-inverting input, the comparator COMP blocks its open-collector output and the supply voltage potential VCC of the further switching signal S S2 remains approximately at the switching terminal IN of
Schaltelements Tl anliegen, so dass dieser weiter eingeschaltet bleibt.Apply switching element Tl, so that it remains turned on.
Nun wird angenommen, dass ein Überlastbetrieb einsetzt, der dadurch gekennzeichnet ist, dass durch das Schaltelement Tl der Laststrom IL fließt, dessen Wert größer oder gleich demIt is now assumed that an overload operation starts, which is characterized in that the load current IL flows through the switching element Tl whose value is greater than or equal to
Wert der vorgegebenen Laststromgrenze ist. Den Laststrom IL repräsentierend, steigt auch der Wert des Sensorstroms IS durch den Shuntwiderstand RS in der Sensorsignaleinheit S U und somit der Spannungswert des Sensorsignals U_IS. Der Spannungswert des Grenzsignals UL am nicht-invertierenden Eingang des Komparators COMP wird durch den Spannungswert des Sensorsignals U IS am invertierenden Eingang überschritten, wodurch der Komparator COMP seinen Open-Collector-Ausgang durchschaltet. Das Schaltsignal S Sl wird durch das Durchschalten des Open-Collector-Ausgangs auf Massepotential GND gelegt, so dass in der Grenzsignaleinheit L_U der Widerstand R3 elektrisch parallel zum Widerstand R2 an Masse GND angeordnet wirkt, wodurch dem Grenzsignal UL die Spannung über den e- lektrisch parallelgeschalteten Widerständen R2 und R3 zugeordnet wird. Der Spannungswert des Grenzsignals UL ist somit im Überlastbetrieb kleiner als im Normalbetrieb des Schaltelements Tl. Gleichzeitig wird der Schaltanschluss IN des Schaltelements Tl mittels des Schaltsignals S_S1 auf Massepotential GND gelegt und somit das Schaltelement Tl abgeschaltet. Der Laststrom IL durch das Schaltelement Tl, sowie der den Laststrom IL repräsentierende Sensorstrom IS sinken auf 0 A. Durch den Shuntwiderstand RS fließt bei abgeschaltetem Schaltelement Tl nur der erste Strom II, wodurch der Spannungswert des Sensorsignals U IS kleiner ist als unmittelbar vor dem Abschalten des Schaltelements Tl im Überlastbetrieb. Da aber auch der Spannungswert des Grenzsignals UL mittels des Schaltsignals S Sl kleiner ist und die Widerstände R4 , R5, RS entsprechend geeignet dimensioniert sind, bleibt der Spannungswert des Sensorsignals U_IS am Komparator COMP weiterhin über dem des Grenzsignals UL, wodurch das Schaltsignal S_S1 mittels des Open-Collector-Ausgangs des Komparators COMP weiterhin auf Massepotential GND liegt und das Schaltelement Tl ausgeschaltet bleibt. Auch mittels des weiteren Schaltsignals S S2 kann das Schaltelement Tl nicht wieder eingeschaltet werden.Value of the given load current limit is. The load current IL representing, the value of the sensor current IS through the shunt resistor RS increases in the sensor signal unit SU and thus the voltage value of the sensor signal U_IS. The voltage value of the limit signal UL at the non-inverting input of the comparator COMP is exceeded by the voltage value of the sensor signal U IS at the inverting input, whereby the comparator COMP turns on its open-collector output. The switching signal S Sl is put through the switching of the open-collector output to ground potential GND, so that in the limit signal unit L_U, the resistor R3 is arranged electrically parallel to the resistor R2 to ground GND, whereby the limit signal UL, the voltage across the e- lektrisch associated in parallel with resistors R2 and R3. The voltage value of the limit signal UL is thus smaller in overload operation than in normal operation of the switching element Tl. At the same time, the switching terminal IN of the switching element Tl is set to ground potential GND by means of the switching signal S_S1 and thus the switching element Tl is switched off. The load current IL through the switching element Tl, as well as the load current IL representing sensor current IS drops to 0 A. Through the shunt resistor RS flows with switched-off switching element Tl only the first current II, whereby the voltage value of the sensor signal U IS is smaller than immediately before switching off of the switching element Tl in overload operation. But since the voltage value of the limit signal UL by means of the switching signal S Sl is smaller and the resistors R4, R5, RS are dimensioned appropriately, the voltage value of the sensor signal U_IS at the comparator COMP remains above that of the limit signal UL, whereby the switching signal S_S1 means of Open collector output of the comparator COMP is still at ground potential GND and the switching element Tl remains off. Also by means of the further switching signal S S2, the switching element Tl can not be turned on again.
Mittels des Resetsignals S_RESET kann die Steuereinheit CTRL das Resetschaltelement T RESET in der Sensorsignaleinheit S U einschalten und somit das Sensorsignal U_IS auf Massepotential GND legen, wodurch eingangsseitig am Komparator COMP der Spannungswert des Grenzsignals UL den des Sensorsignals U_IS überschreitet. Der Komparator COMP sperrt seinen Open- Collector-Ausgang und die noch anliegende Versorgungsspannung VCC des weiteren Schaltsignals S_S2 schalten das Schaltelement Tl wieder ein.By means of the reset signal S_RESET, the control unit CTRL can reset the reset element T RESET in the sensor signal unit SU turn on and thus set the sensor signal U_IS at ground potential GND, whereby the input side of the comparator COMP the voltage value of the limit signal UL exceeds that of the sensor signal U_IS. The comparator COMP blocks its open collector output and the still applied supply voltage VCC of the further switching signal S_S2 turn on the switching element Tl again.
Im Nicht-Überlastbetrieb kann das Schaltelements Tl mittels der Steuereinheit CTRL ausgeschaltet werden, wodurch das weitere Schaltsignal S_S2 und das Schaltsignal S_S1 auf Massepotential GND gelegt werden. Dadurch ist in der Grenzsignaleinheit L U der Widerstand R3 elektrisch parallel zum Widerstand R2 an Masse GND angeordnet, wodurch dem Grenzsignal UL die Spannung über den elektrisch parallelgeschalteten Widerständen R2 und R3 zugeordnet wird. Wie bereits dargestellt, ist dadurch der Spannungswert des Sensorsignals U_IS am invertierenden Eingang des Komparators COMP größer als der des Grenzsignals UL am nicht-invertierenden Eingang, wodurch der Open- Collector-Ausgang des Komparators COMP durchschaltet und das Schaltsignal S_S1 auf Masse GND durchgeschaltet wird.In non-overload operation, the switching element Tl can be turned off by means of the control unit CTRL, whereby the further switching signal S_S2 and the switching signal S_S1 are set to ground potential GND. As a result, in the limit signal unit L U of the resistor R3 is electrically connected in parallel to the resistor R2 to ground GND, whereby the limit signal UL, the voltage across the electrical parallel-connected resistors R2 and R3 is assigned. As already stated, the voltage value of the sensor signal U_IS at the inverting input of the comparator COMP is thereby greater than that of the limit signal UL at the noninverting input, whereby the open collector output of the comparator COMP is turned on and the switching signal S_S1 is switched through to ground GND.
Mittels der Steuereinheit CTRL kann das Schaltelements Tl im Nicht-Überlastbetrieb wieder eingeschaltet werden, wobei ne- ben dem weiteren Schaltsignal S_S2 auch das Resetschaltsignal S_RESET für die vorgegebene Zeitdauer auf das Versorgungs- spannungspotential VCC geschaltet wird. Dadurch wird das Re- setschaltelement T_RESET eingeschaltet und mittels diesem das Sensorsignal U_IS auf Massepotential GND gelegt. Mittels des auf Massepotential GND liegenden Sensorsignals U IS wird der Open-Collector-Ausgang des Komparators COMP gesperrt, wodurch das auf Versorgungsspannungspotential VCC liegende weitere Schaltsignal S_S2 freigegeben und das Schaltelement Tl eingeschaltet wird. Nach Ablauf der vorgegeben Zeitdauer wird das Resetschaltelement T RESET abgeschaltet. In einer weiteren bevorzugten Ausführung umfasst die Sensorsignaleinheit S U einen Kondensator Cl. Dieser ist dem ersten Verknüpfungspunkt VKl und der Masse GND zugeordnet. Der Kondensator Cl bildet mit den Widerständen R4 und R5 einen Tief- passfilter, wodurch zum einen Spannungs- und/der Stromspitzen in der Versorgungsspannung VCC und/oder in dem Sensorstrom IS zur Masse GND abgeleitet werden. Zum Anderen wird durch den Tiefpassfilter das Sensorsignal U_IS verzögert vorgegeben, wodurch kurzzeitige Stromänderungen des Laststromes IL, die im Bereich der durch die vorgegebene Dimensionierung der Widerstände R4 , R5 vorgegebenen Zeitdauer liegen, so z.B. Stromänderungen im Bereich 2 ms bis 5 ms, nicht zum Abschalten des Schaltelements Tl führen.By means of the control unit CTRL, the switching element Tl can be switched on again in the non-overload operation, wherein, in addition to the further switching signal S_S2, the reset switching signal S_RESET is also switched to the supply voltage potential VCC for the predetermined period of time. As a result, the reset switching element T_RESET is turned on and by means of this the sensor signal U_IS is set to ground potential GND. By means of the lying at ground potential GND sensor signal U IS of the open-collector output of the comparator COMP is disabled, whereby the lying on the supply voltage potential VCC further switching signal S_S2 released and the switching element Tl is turned on. After the predetermined time has elapsed, the reset switching element T RESET is switched off. In a further preferred embodiment, the sensor signal unit SU comprises a capacitor Cl. This is assigned to the first node VK1 and the ground GND. The capacitor Cl forms a low-pass filter with the resistors R4 and R5, whereby, on the one hand, voltage and / or current peaks in the supply voltage VCC and / or in the sensor current IS are diverted to ground GND. On the other hand, the sensor signal U_IS is delayed given by the low-pass filter, whereby short-term current changes of the load current IL, which are in the range specified by the predetermined dimensioning of the resistors R4, R5 duration, such as current changes in the range 2 ms to 5 ms, not to shutdown of the switching element Tl lead.
Wird im Nicht-Überlastbetrieb zum Einschalten des Schaltelements Tl neben dem weiteren Schaltsignal S S2 auch das Reset- schaltsignal S_RESET für die vorgegebene Zeitdauer auf Ver- sorgungsspannungspotential VCC gelegt, wird der Kondensator Cl mittels des durchgeschalteten Resetschaltelements T RESET entladen. Nach Ablauf der vorgegebenen Zeitdauer, wird dasIf in non-overload operation for switching on the switching element Tl in addition to the further switching signal S S2 and the reset switching signal S_RESET for supply voltage supply potential VCC for the predetermined period of time, the capacitor Cl is discharged by means of the through-connected reset switching element T RESET. After expiration of the predetermined period of time, the
Resetschaltelement T_RESET mittels Resetsignals S_RESET abgeschaltet und das Sensorsignal U_IS wird durch den mittels Kondensator Cl gebildeten Tiefpassfilter verzögert vorgegeben. Während der verzögerten Vorgabe des Sensorsignals U_IS führen Lastströme IL, die größer sind als die vorgegebene Laststromgrenze, so z.B. typische Einschaltströme bei Beleuchtungsmitteln im Kraftfahrzeug, zu keiner ungewollten Abschaltung des Schaltelements Tl . Des Weiteren können während der vorgegebenen Zeitdauer, in der das Resetschaltelement T_RESET eingeschaltet ist, auch Lastströme IL über der vorgegebenen Laststromgrenze mittels des Schaltelements Tl geführt werden. Auch durch Einschalten des Resetschaltelements T RESET während des eingeschalteten Schaltelements Tl können Lastströme IL über der vorgegebenen Laststromgrenze während dem eingeschalteten Resetschaltelement T_RESET geführt werden . Neben der Ansteuerung von High-Side- und/oder Low-Side- Schaltern, die typischerweise Leistungsfeldeffekttransistoren umfassen, können auch andere Ausführungen von Schaltelementen, so z.B. Bipolartransistoren, etc., mittels der Ansteuervorrichtung C U überwacht werden. Auch sind neben der Verwendung der Ansteuervorrichtung C U im Kraftfahrzeug auch andere Einsatzgebiete der Ansteuervorrichtung C U möglich. Reset switching element T_RESET switched off by means of reset signal S_RESET and the sensor signal U_IS is delayed by the low-pass filter formed by capacitor Cl. During the delayed specification of the sensor signal U_IS load currents IL, which are greater than the predetermined load current limit, such as typical inrush currents in lighting means in the motor vehicle, to no unwanted shutdown of the switching element Tl. Furthermore, during the predetermined time period in which the reset switching element T_RESET is switched on, load currents IL can also be conducted above the predetermined load current limit by means of the switching element T1. By switching on the reset switching element T RESET during the switched-on switching element T1, load currents IL can also be conducted above the predetermined load current limit during the switched-on reset switching element T_RESET. In addition to the control of high-side and / or low-side switches, which typically include power field effect transistors, other types of switching elements, such as bipolar transistors, etc., can be monitored by means of the drive device CU. In addition to the use of the drive device CU in the motor vehicle, other fields of application of the drive device CU are also possible.

Claims

Patentansprüche claims
1. Schaltsystem mit einem Schaltelement (Tl), das einer Last (RL) zugeordnet ist, und mit einer Ansteuervor- richtung (C_U) aufweisend, eine Sensorsignaleinheit (S_U) , die dazu ausgebildet ist, ein Sensorsignal (U_IS), welches repräsentativ ist für einen Laststrom (IL) durch die Last (RL) , zu ermitteln, - eine Grenzsignaleinheit (L_U) , die dazu ausgebildet ist, ein Grenzsignal (UL) , welches repräsentativ ist für eine vorgegebene Laststromgrenze des Laststroms (IL) , vorzugeben und einen Komparator (COMP) , der dazu ausgebildet ist, das eingangsseitig anliegende Sensorsignal (U_IS) mit dem eingangsseitig anliegenden Grenzsignal (UL) zu vergleichen und davon abhängig ausgangsseitig ein Schaltsignal (S_S1) vorzugeben und zwar derart, dass beim Erreichen eines Werts des Grenzsignals (UL) durch das Sensorsignal (U_IS) das Schaltelement (Tl) abgeschaltet wird.A switching system comprising a switching element (T1) associated with a load (RL) and having a driving device (C_U), a sensor signal unit (S_U) adapted to generate a sensor signal (U_IS) representative of the same for a load current (IL) through the load (RL), - a limit signal unit (L_U), which is designed to specify a limit signal (UL) which is representative of a predetermined load current limit of the load current (IL), and a Comparator (COMP), which is adapted to compare the input side applied sensor signal (U_IS) with the input side limit signal (UL) and dependent on the output side, a switching signal (S_S1) to specify such that upon reaching a value of the limit signal (UL ) is switched off by the sensor signal (U_IS), the switching element (Tl).
2. Schaltsystem nach Anspruch 1, bei dem der Komparator2. Switching system according to claim 1, wherein the comparator
(COMP) als Operationsverstärker (OPV) ausgebildet ist, wobei dem Operationsverstärker (OPV) eingangsseitig das Sensorsignal (U IS) und das Grenzsignal (UL) und ausgangsseitig das Schaltsignal (S_S1) zugeordnet ist.(COMP) is designed as an operational amplifier (OPV), wherein the operational amplifier (OPV) on the input side, the sensor signal (U IS) and the limit signal (UL) and the output side, the switching signal (S_S1) is assigned.
3. Schaltsystem nach Anspruch 2, bei dem der Ausgang des Komparators (COMP) als Open-Collector-Ausgang ausgebildet ist.3. Switching system according to claim 2, wherein the output of the comparator (COMP) is designed as an open-collector output.
4. Schaltsystem nach Anspruch 1, bei dem die Sensorsignaleinheit (S_U) als ein Spannungsteiler (R4, R5, RS) aus- gebildet ist und dem Schaltelement (Tl) zugeordnet ist und abhängig von einem Strom (IL) durch das Schaltelement (Tl) das Sensorsignal (U_IS) ermittelt. 4. Switching system according to claim 1, in which the sensor signal unit (S_U) is formed as a voltage divider (R4, R5, RS) and is assigned to the switching element (T1) and dependent on a current (IL) through the switching element (T1) the sensor signal (U_IS) determined.
5. Schaltsystem nach Anspruch 1 oder 4, bei dem die Sensorsignaleinheit (S_U) ein Resetschaltelement (T_RESET) umfasst, das dazu ausgebildet ist, abhängig vom einem dem Resetschaltelement (T RESET) zugeordneten vorgegeben Resetsignal (S_RESET) , das ausgeschaltete Schaltelement (Tl) freizugeben.5. A switching system according to claim 1 or 4, wherein the sensor signal unit (S_U) comprises a reset switching element (T_RESET), which is designed, depending on a the reset switching element (T RESET) assigned predetermined reset signal (S_RESET), the switched-off switching element (Tl) release.
6. Schaltsystem nach Anspruch 1, 4 oder 5, bei dem die Sensorsignaleinheit (S_U) einen Kondensator (Cl) umfasst, der mit einem oder mehreren dem Spannungsteiler zugeordneten Widerständen (R4, R5) als Tiefpass angeordnet und ausgebildet ist, und zwar derart, dass das Sensorsignal (U_IS) tiefpassgefiltert wird.6. Switching system according to claim 1, 4 or 5, wherein the sensor signal unit (S_U) comprises a capacitor (Cl) which is arranged and formed with one or more of the voltage divider associated resistors (R4, R5) as a low-pass filter, and in such a way that the sensor signal (U_IS) is low-pass filtered.
7. Schaltsystem nach Anspruch 1, bei dem die Grenzsignaleinheit (L_U) einen Spannungsteiler (Rl, R2, R3) umfasst .7. Switching system according to claim 1, wherein the limit signal unit (L_U) comprises a voltage divider (Rl, R2, R3).
8. Schaltsystem nach Anspruch 1 oder 7, bei dem das Grenzsignal (UL) abhängig von dem am Komparator (COMP) aus- gangsseitig anliegenden Schaltsignal (S_S1) ist.8. A switching system according to claim 1 or 7, wherein the limit signal (UL) is dependent on the output side of the comparator (COMP) applied switching signal (S_S1).
9. Schaltsystem nach einem der vorstehenden Ansprüche, bei dem das Schaltelement (Tl) als Smart High-Side-Schalter und/oder als Smart Low-Side-Schalter ausgebildet ist und das Sensorsignal (U IS) abhängig von einem dem Smart High-Side- und/oder dem Smart Low-Side-Schalter zugeordneten Sensorstrom (IS) , der repräsentativ ist für einen Strom (IL) durch den High-Side- und/oder dem Smart Low-Side-Schalter, ist.9. Switching system according to one of the preceding claims, wherein the switching element (Tl) is designed as a smart high-side switch and / or as a smart low-side switch and the sensor signal (U IS) depending on a smart high-side - and / or the smart low-side switch associated sensor current (IS), which is representative of a current (IL) through the high-side and / or the smart low-side switch is.
10. Schaltsystem nach einem der vorstehenden Ansprüche, bei dem das Schaltelement (Tl) als Feldeffekt- und/oder als Bipolartransistor ausgebildet ist und das Sensorsignal (U_IS) abhängig vom Strom (IL) durch das entsprechende Schaltelement (Tl) ist. 10. Switching system according to one of the preceding claims, wherein the switching element (Tl) is designed as a field effect and / or as a bipolar transistor and the sensor signal (U_IS) is dependent on the current (IL) through the corresponding switching element (Tl).
PCT/EP2008/058595 2007-08-13 2008-07-03 Switching system WO2009021775A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102007038143.5 2007-08-13
DE200710038143 DE102007038143A1 (en) 2007-08-13 2007-08-13 switching system

Publications (1)

Publication Number Publication Date
WO2009021775A1 true WO2009021775A1 (en) 2009-02-19

Family

ID=40032391

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2008/058595 WO2009021775A1 (en) 2007-08-13 2008-07-03 Switching system

Country Status (2)

Country Link
DE (1) DE102007038143A1 (en)
WO (1) WO2009021775A1 (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040207967A1 (en) * 2001-05-25 2004-10-21 Shunzuo Ohshima Overcurrent detection and protection apparatus for switching element
US20050024900A1 (en) * 2003-07-28 2005-02-03 Matsushita Elec. Ind. Co. Ltd. Semiconductor device
EP1693942A1 (en) * 2005-02-21 2006-08-23 Yazaki Corporation Overcurrent detecting device

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000013279A1 (en) * 1998-08-31 2000-03-09 Siemens Aktiengesellschaft Circuit configuration and method for an electronic fuse
JP2000299924A (en) * 1999-02-14 2000-10-24 Yazaki Corp Power supply control device and method
JP2005341663A (en) * 2004-05-25 2005-12-08 Yazaki Corp Overcurrent detector
DE102005046979B4 (en) * 2005-09-30 2020-03-12 Infineon Technologies Ag Fuse circuit and method for securing a load circuit

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040207967A1 (en) * 2001-05-25 2004-10-21 Shunzuo Ohshima Overcurrent detection and protection apparatus for switching element
US20050024900A1 (en) * 2003-07-28 2005-02-03 Matsushita Elec. Ind. Co. Ltd. Semiconductor device
EP1693942A1 (en) * 2005-02-21 2006-08-23 Yazaki Corporation Overcurrent detecting device

Also Published As

Publication number Publication date
DE102007038143A1 (en) 2009-02-19

Similar Documents

Publication Publication Date Title
DE112006003483B4 (en) Power supply control and threshold setting method therefor
DE19619120A1 (en) Power FET switching and short circuit recognition module
WO2008003534A1 (en) Method and device for recognition of a short circuit in a circuit arrangement
AT408494B (en) PROTECTIVE CIRCUIT FOR AN ELECTRONIC DEVICE
DE102019119975B3 (en) INTELLIGENT ELECTRONIC SWITCH
DE102015218256B4 (en) Speed sensor interface with differential amplifier
DE10118189A1 (en) Test circuit to check state of switch in battery powered equipment operating in standby mode has voltage supply connected to parallel circuit that connects with control unit and switching stage
WO2016078909A1 (en) Protective circuit for overvoltage and/or overcurrent protection
DE19941489A1 (en) Protection circuit for a series connection of power semiconductor output stage and inductive consumer
DE4403375A1 (en) Device and method for controlling an inductive load
EP2203977B1 (en) Circuit configuration for protecting a circuit element having overcurrent and overtemperature detection
DE10356089A1 (en) Circuit arrangement and method for controlling an inductive load
EP0098460B1 (en) Control device for an electrical actuator
EP3017543B1 (en) Circuit arrangement for protecting at least one component part of a two-wire circuit
WO2009021775A1 (en) Switching system
EP2130275A1 (en) Error recognition in a control unit
WO2009103584A1 (en) Method and device for operating a switching unit
DE3815604C2 (en)
DE102007014128B4 (en) Method for operating a circuit arrangement, circuit arrangement and solenoid valve and electronic brake system
EP4078793A1 (en) Circuit assembly for connecting to a current source
WO2016074833A1 (en) Filter device with active control
WO2004082334A1 (en) Heating device comprising a flexible heating part
DE102004020274A1 (en) Method and device for protecting an electronic component
DE102017109684B4 (en) VOLTAGE MEASURING DEVICE, METHOD AND MANUFACTURING METHOD
DE2544482C3 (en) Zener barrier consisting of a current and voltage limiting circuit

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 08774707

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 08774707

Country of ref document: EP

Kind code of ref document: A1