Electronic measuring circuit for an electronic semiconductor switching element

Abstract

An electronic measuring circuit (10) for an electronic semiconductor switching element (21) is disclosed, comprising a first current source (I CC1 ) and a first diode (D1), wherein the first diode (D1) is used to conduct part of a first current (I1) from the first current source (I CC1 ) is configured to form a first connection of the electronic semiconductor switching element (21). The electronic measuring circuit (10) further comprises a second current source (I CC2 ) and a second diode (D2), wherein the second diode (D2) and the second current source (I CC2 ) are configured to conduct another part of the first current (I1) to a second terminal of the electronic semiconductor switching element (21). The second current source (I CC2 ) is further set up and designed so that a separate measuring unit can measure the electrical voltage value of the second current source (I CC2) can measure. Furthermore, an electronic circuit device (20) with the measuring circuit (10) is disclosed.

Description

[0001] The present invention relates to an electronic measuring circuit for an electronic semiconductor switching element. The invention also relates to an electronic circuit device comprising an electronic semiconductor switching element and the electronic measuring circuit.

[0002] In the prior art, measuring circuits for determining the function of an electronic semiconductor switching element are known. These measuring circuits can, for example, detect whether the electronic semiconductor switching element fails due to a fault. The electronic semiconductor switching element can, for instance, exhibit a non-conductive operating state of a load current-carrying channel, a conductive operating state of the load current-carrying channel, or an increased channel resistance of the load current-carrying channel.

[0003] In particular, a failure where the channel resistance exhibits increased resistance can be critical, as thermal overload of the electronic semiconductor switching element can occur, especially in high-voltage applications. This thermal overload can increase the risk of fire for the electronic semiconductor switching element and / or an electronic circuit in which it is integrated. Therefore, close monitoring of the electronic semiconductor switching element's function can be very important.

[0004] From CN 2 04 536 413 U and CN 1 06 569 007 A, circuits are known in which currents are supplied to a semiconductor switch with current sources via two diodes in order to measure a voltage that corresponds to the voltage drop across the switch.

[0005] The object of the present invention is therefore to provide a technology that is more advanced than the prior art. In particular, the accuracy in determining the channel resistance of the load current-carrying channel is to be improved. Measurement uncertainties in determining the channel resistance of the load current-carrying channel are especially preferred to be better compensated for.

[0006] This problem is solved by the items having the features according to the independent claims. Advantageous embodiments are the subject of the dependent claims.

[0007] Disclosed is an electronic measuring circuit for an electronic semiconductor switching element, comprising a first current source and a first diode, wherein the first diode is configured to conduct a portion of a first current from the first current source to a first terminal of the electronic semiconductor switching element. The electronic measuring circuit further comprises a second current source and a second diode, wherein the second diode and the second current source are configured to conduct another portion of the first current to a second terminal of the electronic semiconductor switching element. The second current source is further configured such that a separate measuring unit can measure an electrical voltage value of the second current source.

[0008] For example, the first diode can be designed and configured for connection to the first terminal of the electronic semiconductor switching element. Furthermore, for example, the second current source can be designed and configured for connection to the second terminal of the electronic semiconductor switching element. For example, the electronic measuring circuit can be connected to the electronic semiconductor switching element by arranging the first diode at the first terminal and the second current source at the second terminal. Furthermore, after connection to the electronic semiconductor switching element, the electronic measuring circuit can be used for measurement.

[0009] In particular, half of the first current can be routed through the first diode and half through the second diode. This preferably results in similar operating characteristics for the first and second diodes. For example, the first and second diodes can heat up to a similar, and especially identical, degree and / or exhibit a similar, and especially identical, voltage drop. Preferably, measurement uncertainties caused by temperature effects, for example, can be reduced or compensated for by using the first and second diodes. Particularly preferably, temperature effects can be reduced or compensated for by using the first and second half of the first current.

[0010] Furthermore, the electrical voltage of the second current source can also be configured to represent an electrical voltage of a load current-carrying channel of the electronic semiconductor switching element.

[0011] For example, a voltage loop can be formed consisting of the first diode, the second diode, the second current source, and an electronic semiconductor switching element connected to the electronic measuring circuit. This voltage loop can, in particular, encompass the load-current-carrying channel of the electronic semiconductor switching element while the electronic semiconductor switching element is in a conducting operating state. Specifically, the voltage of the second current source can have a similar nominal voltage value to the voltage of the load-current-carrying channel. The voltage of the load-current-carrying channel, and thus also the voltage of the second current source, can further be used to determine the electrical resistance of the load-current-carrying channel.

[0012] Therefore, the electrical voltage of the second current source can, for example, also be used as a control parameter for controlling the electronic semiconductor switching element. Preferably, the electrical voltage of the second current source can also be used, for example, as a control parameter for controlling the load current. Particularly preferably, the electrical voltage of the second current source can also be used, for example, to deactivate the load current, since it provides information about a failure of the electronic semiconductor switching element. In this way, damage to the electronic semiconductor switching element can, for example, be avoided.

[0013] Furthermore, the first current source and / or the second current source can be designed as a constant current source.

[0014] Preferably, the second current source can be designed as a constant current source, thus improving the accuracy of the measurement of the electrical voltage of the second current source.

[0015] Furthermore, a more precise measurement can, for example, allow for more precise control of an operating point of the electronic semiconductor switching element.

[0016] Furthermore, the first diode and the second diode can be arranged parallel to each other.

[0017] Furthermore, the first diode and the second diode can be arranged in such a way that a temperature is transferred between the first diode and the second diode.

[0018] The first and second diodes can, for example, be arranged side by side. Alternatively or additionally, the casing of the first diode can be in contact with the casing of the second diode.

[0019] Furthermore, the first diode and the second diode can be thermally coupled. In particular, an anode of the first diode and an anode of the second diode can also be thermally coupled.

[0020] Furthermore, thermal influences can be reduced or compensated for in a particularly preferred manner by such arrangements.

[0021] For example, the first diode and the second diode can be coupled to each other by means of a force-fit connection or a material-fit connection.

[0022] Furthermore, the electronic measuring circuit can also include a separate measuring unit designed to measure the electrical voltage value of the second current source. The measuring unit can also be configured to provide the electrical voltage value of the second current source.

[0023] Furthermore, an electronic circuit device with an electronic semiconductor switching element and the disclosed electronic measuring circuit is disclosed.

[0024] The electronic semiconductor switching element and the measuring circuit can be arranged or configured separately from each other. For example, the electronic semiconductor switching element can be arranged or implemented on a first electronic circuit arrangement, and the diagnostic circuit on a second electronic circuit arrangement. Alternatively or additionally, the first circuit arrangement can be configured to provide electrical power. Furthermore, the electronic circuit device can be configured, for example, as a traction inverter, a DC-DC converter, a fuel cell booster, and / or an on-board charger. Alternatively or additionally, the first electronic circuit arrangement and / or the second electronic circuit arrangement can be designed and configured for use in a vehicle.

[0025] Furthermore, the electronic semiconductor switching element can be designed as a transistor switching element, a thyristor switching element or a MOSFET switching element, in particular a high-voltage MOSFET switching element.

[0026] The first connection can be a drain connection of the MOSFET switching element and / or the second connection can be a source connection of the MOSFET switching element.

[0027] The present invention is described in detail below with reference to the figures. These show: Fig. 1. An exemplary electronic measuring circuit for an electronic semiconductor switching element; and Fig. 2 an exemplary electronic circuit device with an electronic semiconductor switching element and the electronic measuring circuit.

[0028] The present invention is described below with reference to preferred embodiments and the figures. However, this description of the embodiment should not be considered exhaustive.

[0029] The Fig. Figure 1 shows an exemplary electronic measuring circuit 10 for an electronic semiconductor switching element 21, which is separate from the electronic measuring circuit 10.

[0030] The electronic measuring circuit 10 comprises a first current source I CC1 and a first diode D1, wherein the first diode D1 is used to conduct a first current I1 from the first current source I CC1 is configured to form a first connection of the electronic semiconductor switching element 21. Furthermore, the electronic measuring circuit 10 comprises a second current source I. CC2 and a second diode D2, wherein the second diode D2 and the second current source I CC2are designed to conduct the first current I1 to a second terminal of the electronic semiconductor switching element 21. Furthermore, the second current source I CC2 set up and trained so that a separate measuring unit can measure the electrical voltage value of the second current source I CC2 can measure.

[0031] Furthermore, the first power source I CC1 and the second power source I CC1 designed as a constant current source.

[0032] Furthermore, the second power source I CC2 be set up and designed in such a way that a separate measuring unit can measure the electrical voltage value of the second current source I CC2 can detect. Furthermore, the electronic measuring circuit 10 can include the separate measuring unit 12, which is used to measure an electrical voltage value of the second current source I. CC2 is trained and / or equipped to provide the electrical voltage value.

[0033] The Fig. Figure 2 shows an exemplary electronic circuit device 20 with an electronic semiconductor switching element 21 and the electronic measuring circuit 10 according to the Fig. 1.

[0034] Furthermore, the electronic semiconductor switching element 21 is configured as a MOSFET switching element, for example, a high-voltage MOSFET switching element. The first terminal is configured as a drain terminal of the MOSFET switching element. The second terminal is configured as a source terminal of the MOSFET switching element. The electronic semiconductor switching element 21 also has a drain-source channel that can be switched between a conductive operating state and a non-conductive operating state.

[0035] Furthermore, the electronic circuit device 20 has a third current source I LOADa load current I2 is directed to the drain terminal of the electronic semiconductor switching element 21. Furthermore, the electronic semiconductor switching element 21 is configured to direct the load current I2 and at least a part, in particular half, of the first current I1 via the drain-source channel.

[0036] Furthermore, the electronic measuring circuit 10 also includes a measuring unit 12, which is used to measure an electrical voltage value V CC2 the second power source I CC2 is configured. Furthermore, at least a portion, in particular half, of the first current I1 is passed through the second diode D2. Additionally, the measuring unit 12 can be used to provide the electrical voltage value V. CC2 the second power source I CC2 be set up.

[0037] Preferably, the first diode D1 and the second diode D2 are of the same diode type or identical in construction. Particularly preferably, the first diode D1 and the second diode D2 are produced within the same production batch. Furthermore preferably, the first diode D1 and the second diode D2 are arranged in parallel to each other. Even more preferably, the first diode D1 and the second diode D2 are arranged such that a temperature is transferred between them. Particularly preferably, the first diode D1 and the second diode D2 are thermally coupled, wherein, in particular, an anode of the first diode D1 and an anode of the second diode D2 are thermally coupled.

[0038] Furthermore, the electrical voltage V CC2 the second power source I CC2designed to represent an electrical voltage of the electronic semiconductor switching element 21. In an electrical voltage loop comprising the electronic semiconductor switching element 21 and the electronic measuring circuit 10, the following relationship exists when the load current I2 has a significantly larger nominal value than the first current I1: VCC2=VF,D1+(I2+I1)∗RDS,on−VF,D2≈I2∗RDS,on

[0039] This corresponds to: V F,D1 an electrical voltage of the first diode D1; V F,D2 an electrical voltage of the second diode D2; and R DS,on an electrical resistance of the drain-source channel.

[0040] By using preferred designs of the first diode D1 and the second diode D2, a possible voltage difference between the electrical voltage V can be reduced. F,D1 the first diode D1 and the electrical voltage V F,D2The second diode D2 can be reduced or compensated for.

[0041] The measuring unit can detect an electrical voltage V CC2 The second power source can supply, for example, an evaluation unit or a control unit. The evaluation unit or control unit can, for example, use the detected electrical voltage V as a basis for its operation. CC2 The second current source determines the function of the electronic semiconductor switching element 21. Furthermore, the evaluation unit or the control unit can, for example, determine the function based on the detected electrical voltage V. CC2 The electronic semiconductor switching element 21 can be switched. Furthermore, the evaluation unit or the control unit can, for example, switch based on the detected electrical voltage V. CC2Switching the load current I2, in particular switching off the load current I2. Switching off the load current can prevent damage to the electronic semiconductor switching element 21. Reference symbol list 10 electronic measuring circuit 12 Unit of measurement D1 first diode D2 second diode I CC1 first power source I CC2 second power source 20 electronic circuit devices 21 electronic semiconductor switching element I LOAD third power source

Claims

[1] Electronic measuring circuit (10) for an electronic semiconductor switching element (21), comprising a first power source (I CC1 ) and a first diode (D1), wherein the first diode (D1) is used to conduct part of a first current (I1) from the first current source (I CC1 ) is formed to form a first connection of the electronic semiconductor switching element (21), and a second power source (I CC2 ) and a second diode (D2), wherein the second diode (D2) and the second current source (I CC2 ) are configured to conduct another part of the first current (I1) to a second terminal of the electronic semiconductor switching element (21), wherein the second current source (I CC2 ) is set up and designed so that a separate measuring unit (21) can measure an electrical voltage value of the second current source (I CC2 can measure. [2] Electronic measuring circuit (10) according to claim 1, wherein the electrical voltage (VCC2 ) the second power source (I CC2 ) is further configured to represent an electrical voltage of a load current-carrying channel of the electronic semiconductor switching element (21). [3] Electronic measuring circuit (10) according to claim 1 or 2, wherein the first current source (I CC1 ) and / or the second power source (I CC1 ) is / are designed as a constant current source. [4] Electronic measuring circuit (10) according to one of claims 1 to 3, wherein the first diode (D1) and the second diode (D2) are arranged in parallel to each other. [5] Electronic measuring circuit (10) according to one of claims 1 to 4, wherein the first diode (D1) and the second diode (D2) are arranged relative to each other such that a temperature is transferred between the first diode (D1) and the second diode (D2). [6] Electronic measuring circuit (10) according to claim 5, wherein the first diode (D1) and the second diode (D2) are thermally coupled together, wherein in particular an anode of the first diode (D1) and an anode of the second diode (D2) are thermally coupled together. [7] Electronic measuring circuit (10) according to any one of claims 1 to 6, wherein the electronic measuring circuit (10) further comprises the separate measuring unit (12) for measuring the electrical voltage value of the second current source (I CC2 ) is trained and / or equipped to provide the electrical voltage value. [8] Electronic circuit device (20) with an electronic semiconductor switching element (21) and the electronic measuring circuit (10) according to one of claims 1 to 7. [9] Electronic circuit device (20) according to claim 8, wherein the electronic semiconductor switching element (21) is configured as a transistor switching element, a thyristor switching element or a MOSFET switching element, in particular a high-voltage MOSFET switching element.

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