Driver circuit with real-time thermal management

Abstract

The invention relates to a driver circuit with real-time thermal management. An electronic circuit for driving an electronic switch is described herein. In one embodiment, an electronic circuit includes: a driver circuit configured to provide a drive signal for an electronic switch in accordance with a control signal; and a multiplier configured to receive, as input signals, a current sense signal representing a current flowing through the load current path of the electronic switch and a voltage sense signal representing a voltage drop across the load current path of the electronic switch. The electronic circuit further includes an estimator circuit configured to receive the multiplier output signal from the multiplier and to generate a temperature signal representative of an estimated temperature of the electronic switch based on the multiplier output signal. Further, the electronic circuit includes a control circuit configured to receive the temperature signal and generate a control signal for the driver circuit based on the temperature signal.

Description

TECHNICAL FIELD

[0001] The present invention relates to the field of driver circuits for driving electronic switches such as Metal Oxide Semiconductor Field Effect Transistors (MOSFETs). BACKGROUND

[0002] When designing an electronic system, it is mandatory to ensure that the semiconductor switches used in the system are only operated within their safe operating area (SOA). For a semiconductor switch, the SOA is usually defined by three parameters. First, the maximum load current must not be exceeded. Second, the maximum voltage (e.g. drain-source voltage for a MOSFET) must not be exceeded, and third, the maximum junction temperature of the semiconductor switch must not be exceeded. While the load current and voltage are parameters that can easily be evaluated by measurement, the junction temperature cannot be evaluated without providing a temperature sensor. In case of an integrated system, a temperature sensor can be available and can be part of the integrated circuit. However, when the system comprises several different semiconductor devices (i.e. when the driver circuit and the semiconductor switch are not part of the same integrated circuit), it can be challenging to evaluate the junction temperature of the semiconductor switch and providing an external temperature sensor can increase system complexity and cost.

[0003] An additional temperature sensor with potentially additional signal conditioning blocks (filters, biasing, etc.) can result in a more expensive system. The temperature sensor can only be placed on the circuit board (PCB) which can not be used to detect fast transient temperature spikes (e.g. 100 μβ or 1 ms) in the active area of the semiconductor switch. Additionally, providing a temperature sensor can interfere with the layout of the PCB and the PCB traces have to be routed differently, further increasing the overall system complexity.

[0004] There is a need for a driver circuit that is able to provide over-temperature protection for an external electronic switch without relying on a temperature sensor in order to ensure that the semiconductor switch is operated within its SOA. Furthermore, it can be desirable to have a dedicated configurability of the over-temperature protection function. SUMMARY

[0005] An electronic circuit for driving an electronic switch is described herein. In one embodiment, the electronic circuit comprises a driver circuit configured to provide a drive signal for the electronic switch in dependence on a control signal, and a multiplier configured to receive, as input signals, a current sense signal representing a current flowing through a load current path of the electronic switch and a voltage sense signal representing a voltage drop across the load current path of the electronic switch. The electronic circuit further comprises an estimator circuit configured to receive a multiplier output signal from the multiplier and to generate, based on the multiplier output signal, a temperature signal representing an estimated temperature of the electronic switch. Furthermore, the electronic switch comprises a control circuit configured to receive the temperature signal and to generate, based on the temperature signal, the control signal for the driver circuit. Another embodiment relates to a system comprising the above-mentioned electronic circuit and the electronic switch. BRIEF DESCRIPTION OF DRAWINGS

[0006] The embodiments described herein can be better understood with reference to the following description and drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the embodiments. Furthermore, in the drawings, like reference numerals designate corresponding parts throughout the several views. In the drawings:

[0007] Figure 1 A basic structure of a system comprising an electronic circuit (e.g. a driver IC) for driving an electronic switch, such as a power MOSFET, is illustrated.

[0008] Figure 2 One embodiment of an electronic circuit with a gate driver and an estimator capable of estimating an external switch temperature is illustrated.

[0009] Figure 3 An embodiment of Figure 2 is illustrated in more detail.

[0010] Figure 4 One exemplary implementation of an estimator circuit is illustrated.

[0011] Figure 5 A modification of the example of Figure 2 is illustrated.

[0012] Figure 6 The example of Figure 5 is illustrated in more detail.

[0013] Figure 7 One exemplary implementation of an estimator circuit with a filter bank consisting of three first order low pass filters is illustrated.

[0014] Figure 8 is a plot illustrating that the behavior of the estimator can be adapted to a given curve representing a specific thermal behavior of an external electronic switch.

[0015] Figure 9 The switching of the external electronic switch during the on-period of the capacitive load is illustrated. DETAILED DESCRIPTION

[0016] So-called "smart switches" are integrated circuits (ICs) that include one or more electronic switches (e.g. power MOS transistors), corresponding driver circuits (e.g. gate drivers) and supplementary circuitry in a single semiconductor die, which can provide, for example, over-temperature protection functions and over-current protection functions. This single-chip approach typically allows the use of temperature sensors that can be integrated within (or very close to) the array of transistor cells that form the power transistors. In integrated circuits, pn junctions are typically used as temperature sensors.

[0017] However, in some applications, discrete driver circuits (driver ICs) are used to drive discrete electronic switches (such as power MOSFETs), which typically do not have an integrated temperature sensor. Although there are discrete power transistors with integrated temperature sensors, the use of such devices can be undesirable because the temperature sensor signal has to be pre-processed by some signal conditioning circuitry and then routed via the PCB to the driver IC, which adds complexity and total cost to the system design. The embodiments described herein allow temperature protection features in the driver IC without requiring a temperature sensor for direct measurement of temperature information.

[0018] If the temperature of a circuit component is to be evaluated without direct or indirect measurement of the temperature, a simulation of the thermal behavior of the circuit component can be considered. For example, in the case of a wire, its thermal behavior can be estimated from the load current. The resistance of the wire does not change significantly during operation and thus the load current i L and the knowledge of the resistance R of the wire is sufficient to estimate the power dissipation in the wire, where the dissipated power P is proportional to the square of the load current i L (P = R · i L 2 The same concept can be used to determine the temperature of other passive resistive components, such as connectors or conductive tracks of a PCB.

[0019] However, active components, such as semiconductor switches, experience a considerable variation of their output resistance depending on their operating mode (linear mode, saturation mode, switching, clamping, etc.) and thus (unlike a simple wire) R cannot be considered a constant parameter.

[0020] Figure 1The diagram illustrates the basic structure of a system including electronic circuitry 10 (e.g., a driver IC) for driving a power MOSFET 40. In this context, "driving a power MOSFET" means providing a gate voltage / current to turn the power MOSFET on and off. It should be understood that the concepts described herein are not limited to MOSFETs. Any other type of electronic switch, such as a bipolar junction transistor (BJT), an insulated-gate bipolar transistor (IGBT), or a junction field-effect transistor (JEFT), may also be used. For some types of electronic switches, the control electrode is not referred to as the "gate" (e.g., the control electrode of a BJT is referred to as the base). However, the use of the terms gate voltage and gate current in the following discussion should not be interpreted as limiting the corresponding embodiments to transistors that actually have a gate electrode. As mentioned, the concepts described herein can be readily applied to other types of electronic switches, such as BJTs that require base current instead of gate current.

[0021] Figure 1 The circuit includes a current sensing circuit, which can be a simple current-sensing resistor connected in series with the load current path of the electronic switch 40. In this example, the current-sensing resistor R CS A shunt resistor is connected between the source electrode of MOSFET 40 and the load Z. A current-sensing resistor R... CS voltage drop V CS It can be used as a current sensing signal, which in Figure 1 The middle is marked as S CS Apply equation V CS =i L ·R CS , where i L This represents the load current passing through MOSFET 40. In the equations and formulas, R... CS This indicates the resistance of the current sensing resistor.

[0022] MOSFET 40 is connected in a high-side configuration, where a load Z is coupled between MOSFET 40 and ground potential (or any other constant reference potential). In this case, the drain electrode of MOSFET 40 is connected to the supply voltage V. B (e.g., the battery voltage of an onboard battery in automotive applications) voltage source.

[0023] Electronic circuit 10 is configured to output drive signal S ON (e.g., gate voltage V) G This turns MOSFET40 on and off. During normal operation, the drive signal S... ONThe switching commands can be generated in accordance with a current sense signal S In the present example, the electronic circuit comprises a serial peripheral interface (SPI) which allows to receive digital information (e.g. data and commands) from an external controller, in the present example a microcontroller 20. It should be understood that the SPI bus is merely an illustrative example which can be replaced by other communication links (i.e. physical connections and communication protocols). In some examples, the electronic circuit 10 comprises an input pin for receiving a logic signal. In this example, a transition of the logic signal from low to high (or vice versa) can be considered as a switching command for turning on (or off) the electronic switch.

[0024] The electronic circuit 10 also receives a current sense signal S CS and a voltage sense signal S VC The voltage sense signal S VC is indicative of the voltage drop V DS (drain-source voltage) across the load current path of the MOSFET 40. The electronic circuit 10 can process the current sense signal S CS to implement an overcurrent protection function which causes the turn-off of the electronic circuit 40 in case of overcurrent or short circuit. When using a n-channel MOSFET in a high-side configuration, the electronic circuit 10 needs to receive a supply voltage V B and a source voltage V S in order to be able to provide (e.g. using a charge pump) a gate voltage V G which can be higher than the supply voltage V B .

[0025] In the present example, the power supply circuit 30 provides a supply current V DD for the electronic circuit 10 and the microcontroller 20. The power supply circuit 30 can comprise a voltage regulator and generate the supply current V DD from a (higher) supply voltage V S . Although the supply current V DD may for example be between 2.5 and 5 volts, the supply voltage V B may be 12 volts more.

[0026] The microcontroller 20 can be configured to digitally communicate with the electronic circuit 10. In the present example, the microcontroller 20 and the electronic circuit 10 are equipped with a serial peripheral interface (SPI). The SPI is connected via a bus to exchange serial data. Furthermore, the microcontroller 20 can have a controller area network (CAN) interface to communicate with a superior system controller. It should be understood that any other communication link and protocol can be used instead of CAN or SPI.

[0027] As mentioned, electronic circuit 10 serves as a driver IC that drives power transistor 40 to turn it on and off. Electronic circuit 10 can be configured to turn power transistor 40 on and off according to switching commands received from microcontroller 20 via the SPI bus. In addition, electronic circuit 20 can provide protection functions such as overcurrent shutdown or current limiting, undervoltage detection, etc. Over-temperature protection is a common feature of smart switches, which consist of a power transistor and control / driver circuitry within a single semiconductor die. Temperature information indicating the power transistor's temperature is not available in electronic circuit 10 because power transistor 40 is a discrete transistor integrated into a single semiconductor die.

[0028] Figure 2 An embodiment of an electronic circuit is illustrated, which allows for over-temperature protection of an external semiconductor switch 40 without receiving any temperature information. Figure 2 The circuit basically includes and Figure 1 The same components as those in the circuit are shown in more detail in the electronic circuit 10. Therefore, the electronic circuit 10 includes a driver circuit 14, which is configured to respond to the control signal S. ON Provides drive signal S for power transistor 40 ON (e.g., gate voltage V) G or gate current i G The control signal S ON These are logic signals that can be assumed to be low or high levels. When a MOS transistor is used, this type of driver circuit is usually called a gate driver.

[0029] If you have already referred to Figure 1 As explained, electronic circuit 10 receives current sensing signal S CS (representing the load current i passing through power transistor 40) L ) and voltage sensing signal S VS (V represents the voltage drop V along the load current path of the power transistor 40) DS According to the embodiments discussed herein, the electronic circuit includes a multiplier 15 that receives a current sensing signal S. CS and voltage sensing signal S VS As the input signal, the output signal of multiplier 15 represents the power P, where in this example P = i L ·V DS Product i L ·V DS This indicates the power dissipated in power transistor 40.

[0030] Multiplier output signal (power signal P) SWThe multiplier itself does not indicate temperature. However, it can be used as input to a thermal model of a power transistor. In this example, electronic circuit 10 includes estimator circuit 13, which receives the multiplier output signal P from multiplier 15. SW And it generates a temperature signal T representing the estimated temperature of the power transistor 40. SW The estimator circuit is configured to be based on the power signal P. SW Determine (estimate) temperature T SW Furthermore, the electronic circuit 10 includes a control circuit 12 configured to receive a temperature signal T. SW And based on the temperature signal T SW Generate control signal S for driver circuit 14 ON In other words, the control signal S ON It depends on the estimated temperature.

[0031] For example, control circuit 12 can be configured to output a control signal S having a first level (e.g., a low level). ON When the temperature signal T SW When the first threshold is exceeded, the first level causes the driver circuit 14 to turn off the electronic switch 40. Conversely, the control circuit 12 can be configured to output a control signal S with a second level (e.g., a high level). ON When the temperature signal T SW When the voltage drops below a second threshold, this second level causes the driver circuit 14 to turn on the electronic switch 40. The first and second thresholds can be configurable and respond to configuration data S. CF It is set by receiving (via SPI interface 11). Figure 3 The example illustration shows the function.

[0032] Figure 3 circuit and Figure 1 The circuit is the same, but it is shown in more detail. Figure 2 A simplified embodiment of the control circuit. Therefore, the control circuit 12 receives the input signal S. IN Input signal S IN It can be a logic signal (through its logic level) indicating the desired switching state of power transistor 40. Therefore, when S... IN When the signal is high, the control circuit 12 can send a signal to the gate driver 14 to turn on the power transistor 40. Conversely, when S... IN When the signal is low, control circuit 12 can send a signal to gate driver 14 to turn off power transistor 40. Input signal S IN It can be received via dedicated chip pins or (e.g.) Figure 3 (As shown) is generated via communication interface 11 based on the switch command received via a communication link (e.g., SPI bus).

[0033] When the estimated temperature T is provided by estimator circuit 13 SW When the temperature is too high, the input signal S IN This can be ignored. The first and second thresholds mentioned above can be implemented using comparators with hysteresis. According to... Figure 3 The control circuit 12 includes a comparator K, which has a hysteresis defined by a first threshold and a second threshold. The output and input signals S of the comparator K are... IN It is provided as input to the AND gate Q. As long as the temperature T... SW If the input signal S is below the first threshold, comparator K outputs a high level, and therefore AND gate Q is transparent, meaning it will output a high level to the input signal S. IN The logic level is forwarded to gate driver 14, which charges the gate of power transistor 40 to turn it on (and keeps it in the on state). When temperature T SW If the first threshold is exceeded, comparator K outputs a low level, and therefore AND gate Q becomes no longer transparent and the input signal S... IN Blanking. Therefore, the AND gate Q outputs a low level to gate driver 14, which discharges the gate of power transistor 40 to turn it off (and keeps it off). The output of comparator K will remain low (thus blanking the input signal with the help of the AND gate) until the estimated temperature T. SW It drops below the second threshold, where the second threshold is lower than the first threshold.

[0034] As discussed above, the estimator circuit 13 receives the multiplier output signal P from the multiplier 15. SW (Power signal), and uses the thermal model of power transistor 40 to generate a temperature signal T representing the estimated temperature of power transistor 40. SW Thermal models can be derived, for example, from... Figure 4 The filter bank shown is used to implement this.

[0035] according to Figure 4 In the example shown, the estimator circuit 13 may include multiple filters F1, F2, ..., F n A filter bank consisting of n filters. Each of the n filters can be a first-order filter, such as a first-order low-pass filter. Filters F1, F2, ..., F n Received power signal P SW As the input signal. Where filters F1, F2, ..., F... n The output signal is summed by the adder. The summed signal T generated by the adder is... SW This can be interpreted as the estimated temperature of the electronic switch.

[0036] In one example, (at least) three first order filters are used (F1, F2, F3) n = 3). Thus, each filter F1, F2, F3 has a gain and a time constant. In this example, the behavior of the estimator is determined by six parameters (three gains and three time constants). These parameters are configurable and can be set according to configuration parameters S CF received from an external controller via the SPI interface 11 and stored in a memory. CF In one example, the configuration parameters S CF are stored in a non-volatile memory (see for example Figure 6 ). The memory can be considered as part of the communication interface or as a separate subsystem of the circuit 10.

[0037] In the example of Figure 3 , the multipliers 15 are analog multipliers and the estimator circuit 13 comprises analog filters. However, the electronic circuit 10 can comprise an analog-to-digital converter (ADC) circuit 16 as shown in the example of Figure 5 . According to Figure 5 , the ADC circuit 16 receives the signals S VC and S CS and generates corresponding digital signals S VC ' and S CS '. The use of the ADC circuit 16 allows a digital implementation of the multipliers 15 and of the estimator circuit 13. Thus, in the example of Figure 5 , the multipliers 15 and the estimator circuit 13 are digital circuits, i.e. these circuits can be implemented using a memory and a processor configured to execute firmware instructions stored in the memory to perform the described functions (multiplication and filtering). Additionally or alternatively, hardwired arithmetic and logic circuits can be used. The ADC circuit 16 can comprise more ADCs operating in parallel. Alternatively, the ADC circuit 16 can comprise a multiplexer which allows converting two (or more) analog signals with a single ADC. Moreover, the ADC circuit 16 can comprise a sample-and-hold (S&H) circuit.

[0038] Figure 6 Another example is illustrated which is substantially the same as in Figure 5 , wherein the estimator circuit 12 and the control circuit 12 are shown in more detail. Thus, the control circuit 12 can comprise a comparator with hysteresis as discussed above with reference to Figure 3 . Figure 6 It is also shown that a reference temperature signal T REF is received by the comparator with hysteresis. The hysteresis can depend on the reference temperature signal. In addition to this, the control circuit 12 can comprise a second comparator without hysteresis which is configured to compare the temperature T SWreaches a third threshold IN blanking. In the present example, the output signal of the second comparator is latched (stored) by a flip-flop. Thus, once the temperature T SW reaches a third threshold (which can be higher than the second threshold), the input signal S IN is blanked and remains blanked until the flip-flop is reset. The reset signal of the flip-flop can be provided by the SPI interface 11, e.g. in response to a reset command received via the SPI bus.

[0039] The estimator 13 consists of three digital filters F1, F2, F3, which receive the same digital input signal P SW ' (the output of the digital multiplier 15). The outputs of the three filters F1, F2, F3 are summed, and the summed signal T SW is output to the above-mentioned comparator with hysteresis. Each filter can be a first order filter. In particular, a first order low pass filter. In one example, each filter can be an IIR (infinite impulse response) filter, which can be represented by a gain and a time constant.

[0040] Figure 7 The example of Fig. 3 illustrates the transfer functions (in the form of the Laplace transform of the impulse response) of the three filters F1, F2 and F3 in the analog domain. The parameters R1, R2 and R3 are the filter gains, and the parameters τ1, τ2 and τ3 are the filter time constants. The variable s is the complex frequency parameter. As mentioned, these parameters can be configurable (parameter set S CF ). In a digital implementation, the Laplace transform can be replaced by a z-transform, which can have the form a1 / (1-b1-z -1 ), where a1 and b1 are parameters representing (depending on) the gain R1 and the time constant τ1 of the filter.

[0041] By choosing appropriate filter parameters, the estimator 12 can be adapted to the thermal behavior of a specific power transistor. Figure 8 is a graph taken from a data sheet of a power MOSFET. It illustrates (among others) the temperature (K / M) per Watt (Watt) resulting over a pulse time. The bottom line represents the dependence of the temperature (normalized with respect to the input power) on the pulse length of the MOSFET. The dots are the estimated values generated by the estimator circuit 12 (with an appropriate parameter set). It can be seen that the estimated temperature values match the actual thermal behavior of the MOSFET (represented by the graph in the data sheet).

[0042] Figure 9 Fig. 4 illustrates the switching of the power transistor 40 during the on period, when a capacitive load is connected to the power transistor 40. Figure 9The fourth (bottom) figure illustrates the estimated temperature variation between approximately 20 K (second threshold) and 35 K (first threshold). Figure 9 The first (top) and second figures respectively illustrate the oscillating load current (current sensing signal S). CS ) and oscillation voltage (voltage sensing signal S) VS As explained above, the oscillation is due to the fact that control circuit 12 causes power transistor 40 to turn off when the estimated temperature reaches the first threshold, and only when the estimated temperature has dropped to the second threshold does control circuit 12 cause power transistor 40 to turn on. Figure 3 illustrates the multiplier output (power signal P). SW ).

[0043] It can be seen that, with the capacitive load C (see...), Figure 6 Gradual charging (gradual charging in each cycle), the voltage across the power transistor (as determined by S) VS (This indicates that) the load current (as indicated by S) decreases as the voltage across the capacitive load increases. Therefore, the load current (as indicated by S) decreases. CS (This indicates) a gradual increase.

[0044] Finally, it should be noted that electronic circuit 10 can be configured to drive / control more than one MOSFET (or other electronic switch). In this case, electronic circuit 10 is referred to as having multiple channels. In such a multi-channel embodiment, a gate driver 14, a multiplier 15, and an estimator current 13 can be provided for each channel. Communication interface 11 and control circuit 12 can be configured to cooperate with components of all channels.

[0045] The following provides an overview of examples of this disclosure. It should be understood that the following is not an exhaustive enumeration but rather an exemplary overview. The technical features of the examples can be combined to generate other examples.

[0046] Example 1: Electronic circuit 10 includes: driver circuit 14, configured to respond to control signal S ON Provides drive signal S for electronic switch 40 ON Multiplier 15 is configured to receive a current sensing signal S as an input signal. CS and voltage sensing signal S VS Current sensing signal S CS The load current i represents the load current path passing through the electronic switch 40. L Voltage sensing signal S VS V represents the voltage drop across the load current path. DS The estimator circuit 13 is configured to receive the multiplier output signal P from the multiplier 15. SW (Power signal), and based on the multiplier output signal P SW Generate temperature signal TSW a temperature signal T SW representing an estimated temperature of the electronic switch 40; and a control circuit 12 configured to receive the temperature signal T SW and to generate a control signal S SW for the driver circuit 14 based on the temperature signal T ON .

[0047] Example 2: The electronic circuit according to example 1, wherein the control circuit 12 is configured to output the control signal S ON with a first level (e.g. a low level) that causes the driver circuit 14 to turn off the electronic switch 40 when the temperature signal T SW exceeds a first threshold value.

[0048] Example 3: The electronic circuit according to example 1 or 2, wherein the control circuit 12 is configured to output the control signal S ON with a second level (e.g. a high level) that causes the driver circuit 14 to turn on the electronic switch 40 when the temperature signal T SW drops below a second threshold value. The first threshold value and the second threshold value determine a hysteresis.

[0049] Example 4: The electronic circuit according to any one of examples 1 to 3, wherein the control circuit 12 is configured to output the control signal S ON with the first level that causes the driver circuit 14 to turn off the electronic switch 40 when the temperature signal T SW exceeds a third threshold value, and to keep the electronic switch 40 in the turned-off state until a reset (see e.g. the RS flip-flop of Figure 6 ).

[0050] Example 5: The electronic circuit according to example 2 or 3, wherein the first threshold value and the second threshold value each represent a respective temperature difference between a junction temperature of an active region of the electronic switch 40 and a chip temperature remote from the active region.

[0051] Example 6: The electronic circuit according to any one of examples 1 to 5, wherein the estimator circuit 13 comprises a low-pass filter, wherein the temperature signal T SW represents a low-pass filtered multiplier output signal P SW .

[0052] Example 7: The electronic circuit according to any one of examples 1 to 5, wherein the estimator circuit 13 uses the multiplier output signal P SW as an input to simulate a thermal response of the electronic switch 40.

[0053] Example 8: The electronic circuit according to example 6, wherein the estimator circuit 13 is configured to receive one or more (configuration) parameters SCF , the parameter S CF represents at least one filter parameter, such as a filter gain and a filter time constant.

[0054] Example 9: The electronic circuit according to any one of the examples 1 to 8, wherein the electronic circuit 10 further comprises an analog-to-digital converter circuit 16 configured to convert the current sense signal S CS and the voltage sense signal S VS into a digital current sense signal S CS ’ and a digital voltage sense signal S VS ’, respectively, and wherein the multiplier 15 is configured to multiply the digital current sense signal S CS ’ and the digital voltage sense signal S VS ’.

[0055] Example 11 : The electronic circuit according to any one of the examples 1 to 10, the control circuit 12 comprising a first comparator configured to receive the temperature signal T SW .

[0056] Example 12: The electronic circuit according to example 10, wherein the first comparator has a hysteresis (which determines e.g. the first and second threshold values proposed).

[0057] Example 13: The electronic circuit according to any one of the examples 1 to 10, wherein the control circuit 12 comprises a first comparator configured to receive the temperature signal T SW and a reference signal representing a temperature threshold value (in one example, the first and second threshold values can be derived from the temperature threshold value).

[0058] Example 14: The electronic circuit according to example 11, wherein the control circuit 12 further comprises a logic circuit configured to receive an output signal of the first comparator and an input signal of the electronic switch (S IN ), and wherein the logic circuit outputs a control signal S ON for the driver circuit 14.

[0059] Example 15: The electronic circuit according to any one of the examples 1 to 14, wherein the electronic circuit 10 further comprises a communication interface 11 coupled to the control circuit 12, wherein the control circuit 12 is configured to receive information from an external controller 20 via the communication interface 11.

[0060] Example 16: According to example 15, wherein the communication interface 11 is coupled to the estimator circuit 13, wherein the estimator circuit 13 is configured to receive information from the external controller 20 via the communication interface 11.

[0061] Example 17: According to Example 15 or 16, the information received by the estimator circuit 13 from the communication interface 11 is stored in a non-volatile memory.

[0062] Example 18: According to Example 15, when referring to Example 8, where communication interface 11 is configured to receive from an external controller a representation of at least one filter parameter S CF The data.

[0063] Example 19: The electronic circuit according to any one of Examples 1 to 17 further includes: at least one first chip contact configured to receive a current sensing signal S. CS and at least one second chip contact, configured to receive a voltage sensing signal S VS .

[0064] Example 20: A system comprising: an electronic switch 40 integrated in a first semiconductor die; and an electronic circuit 10 integrated in a second semiconductor die, wherein the electronic circuit 10 includes: a driver circuit 14 configured to respond to a control signal S. ON Drive signal S ON 'Provided to electronic switch 40; multiplier 15, configured to receive current sensing signal S as input signal' CS and voltage sensing signal S VS Current sensing signal S CS The load current i represents the load current path passing through the electronic switch 40. L Voltage sensing signal S VS V represents the voltage drop across the load current path. DS The estimator circuit 13 is configured to receive the multiplier output signal P from the multiplier 15. SW And based on the multiplier output signal P SW Generate temperature signal T SW Temperature signal T SW The electronic switch 40 represents the estimated temperature; the control circuit 12 is configured to receive the temperature signal T. SW And based on the temperature signal T SW Generate control signal S for driver circuit 14 ON .

[0065] Example 21: The system according to Example 20, wherein the first semiconductor die and the second semiconductor die are integrated in a chip package.

[0066] While the application has been illustrated and described with reference to one or more implementations, alternatives and / or modifications can become apparent to those skilled in the art. In particular, with reference to the various functions performed by the components or structures (units, assemblies, devices, circuits, systems, etc.) described above, unless otherwise indicated, the terms used are intended to correspond, where appropriate, to any component or structure which functions to perform the described function of the specified component (e.g., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the illustrated implementations of the application.

Claims

1. An electronic circuit (10), comprising: The driver circuit (14) is configured to respond to the control signal (S) ON ) provides a drive signal (S) for the electronic switch (40). ON '); The multiplier (15) is configured to receive a current sensing signal (S) as an input signal. CS ) and voltage sensing signal (S VS The current sensing signal (S) CS ) represents the load current (i) passing through the load current path of the electronic switch (40). L The voltage sensing signal (S) VS ) represents the voltage drop across the load current path (V DS ); The estimator circuit (13) is configured to receive the multiplier output signal (P) from the multiplier (15). SW ), and based on the multiplier output signal (P) SW ) Generate temperature signal (T) SW The temperature signal (T) SW ) represents the estimated temperature of the electronic switch (40); The control circuit (12) is configured to receive the temperature signal (T). SW ), and based on the temperature signal T SW The control signal (S) for generating the driver circuit (14) is generated. ON ).

2. The electronic circuit according to claim 1, The control circuit (12) is configured to output the control signal (S) having a first level. ON When the temperature signal (T) SW When the first level exceeds the first threshold, the first level causes the driver circuit (14) to turn off the electronic switch (40).

3. The electronic circuit according to claim 1 or 2, The control circuit (12) is configured to output the control signal (S) having a second level. ON When the temperature signal (T) SW When the voltage drops below the second threshold, the second level causes the driver circuit (14) to turn on the electronic switch (40).

4. The electronic circuit according to any one of claims 1 to 3, The control circuit (12) is configured to output the control signal (S) having the first level. ON When the temperature signal (T) SW When the third threshold is exceeded, the first level causes the driver circuit (14) to turn off the electronic switch (40) and keep the electronic switch (40) in the off state until reset.

5. The electronic circuit according to claim 2 or 3, The first threshold and the second threshold represent the temperature difference between the junction temperature of the active region of the electronic switch (40) and the chip temperature away from the active region.

6. The electronic circuit according to any one of claims 1 to 5, The estimator circuit (13) includes a low-pass filter, wherein the temperature signal (T) SW ) represents the multiplier output signal (P) after low-pass filtering. SW ).

7. The electronic circuit according to any one of claims 1 to 5, wherein the estimator circuit (13) uses the multiplier output signal (P) SW The thermal response of the electronic switch (40) is simulated using the input as an example.

8. The electronic circuit according to claim 6, The estimator circuit (13) is configured to receive one or more parameters (S) CF ), the parameter (S) CF () represents at least one filter parameter, such as filter gain and filter time constant.

9. The electronic circuit according to any one of claims 1 to 8, wherein the electronic circuit (10) further comprises: The analog-to-digital converter circuit (16) is configured to convert the current sensing signal (S) into digital signal (S) CS ) and the voltage sensing signal (S) VS ) are respectively converted into digital current sensing signals (S) CS ') and digital voltage sensing signal (S VS '), The multiplier (15) is configured to multiply the digital current sensing signal (S) CS ') and the digital voltage sensing signal (S) VS Multiply by ').

10. The electronic circuit according to any one of claims 1 to 9, The control circuit (12) includes a first comparator configured to receive the temperature signal (T). SW ).

11. The electronic circuit according to claim 9, The first comparator has hysteresis.

12. The electronic circuit according to any one of claims 1 to 9, The control circuit (12) includes a first comparator configured to receive the temperature signal (T). SW ) and a reference signal representing the temperature threshold (T) REF ).

13. The electronic circuit according to claim 10, The control circuit (12) further includes a logic circuit configured to receive the output signal of the first comparator and the input signal (S) of the electronic switch. IN ),as well as The logic circuit outputs the control signal (S) for the driver circuit (14). ON ).

14. The electronic circuit according to any one of claims 1 to 13, The electronic circuit (10) further includes a communication interface (11) coupled to the control circuit (12), wherein the control circuit (12) is configured to receive information from an external controller (20) via the communication interface (11).

15. The electronic circuit according to claim 14, The communication interface (11) is coupled to the estimator circuit (13), wherein the estimator circuit (13) is configured to receive information from the external controller (20) via the communication interface (11).

16. The electronic circuit according to claim 14 or 15, The information received by the estimator circuit (13) from the communication interface (11) is stored in a non-volatile memory.

17. The electronic circuit according to claim 14, when claim 8 is referenced, The communication interface (11) is configured to receive, from the external controller, a representation of the at least one filter parameter (S). CF (Data).

18. The electronic circuit according to any one of claims 1 to 16, further comprising: At least one first chip contact is configured to receive the current sensing signal (S) CS ),as well as At least one second chip contact is configured to receive the voltage sensing signal (S) VS ).

19. A system comprising: An electronic switch (40) is integrated into the first semiconductor die; Electronic circuit (10), integrated in a second semiconductor die, said electronic circuit (10) includes: The driver circuit (14) is configured to respond to the control signal (S) ON ) will drive signal (S ON ') is provided to the electronic switch (40); The multiplier (15) is configured to receive a current sensing signal (S) as an input signal. CS ) and voltage sensing signal (S VS The current sensing signal (S) CS ) represents the load current (i) passing through the load current path of the electronic switch (40). L The voltage sensing signal (S) VS ) represents the voltage drop across the load current path (V DS ); The estimator circuit (13) is configured to receive the multiplier output signal (P) from the multiplier (15). SW ), and based on the multiplier output signal (P) SW ) Generate temperature signal (T) SW The temperature signal (T) SW ) represents the estimated temperature of the electronic switch (40); The control circuit (12) is configured to receive the temperature signal (T). SW ), and based on the temperature signal (T) SW ) generates the control signal (S) for the driver circuit (14). ON ).

20. The system according to claim 19, The first semiconductor die and the second semiconductor die are integrated in a single chip package.

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