Device including power transistor

Abstract

A device is provided that includes a power transistor having a control terminal coupled to a control node. The power supply circuit is coupled to the control node and includes an output capacitor, and is configured to provide a supply voltage at the output capacitor to power another circuit.

Description

Technical Field

[0001] The present application relates to devices including power transistors. Background Art

[0002] Power transistors are used in a variety of applications to switch power (i.e., current and voltage), such as high currents up to hundreds of amperes or high voltages up to thousands of volts. The term "power transistor" as used herein also includes transistors in which multiple transistor cells are coupled in series (e.g., stacked) to increase voltage handling capability, or coupled in parallel to increase current handling capability.

[0003] The power transistor may be provided in a package with another circuit. Such another circuit may include circuitry that monitors the current through the power transistor to detect overcurrent, and may take countermeasures such as shutting down the power transistor in the event of overcurrent, or may include other diagnostic circuitry. Such another circuit may require power to operate.

[0004] Examples for such a device are described in US 2017 / 288385 A1, JP 2005-020843 A, or implemented in the M17561L-01 hybrid IC of Ishaya Electronics Corporation. Summary of the invention

[0005] According to a first aspect, there is provided a device comprising:

[0006] a power transistor comprising a first load terminal, a second load terminal and a control terminal,

[0007] a device control node coupled to the control terminal,

[0008] A power supply circuit is coupled to the device control node and includes:

[0009] a rectifier arrangement coupled between the device control node and an input side of a charge pump, wherein an output side of the charge pump is coupled to an output capacitor,

[0010] Therein, a power supply circuit is configured to provide a supply voltage at an output capacitor, and another circuit is configured to be powered by the supply voltage.

[0011] According to a second aspect, there is provided a device comprising:

[0012] a power transistor comprising a first load terminal, a second load terminal and a control terminal,

[0013] a device control node coupled to the control terminal,

[0014] a power supply circuit coupled to the device control node and comprising at least one output capacitor and at least one diode coupled between the device control node and the output capacitor, wherein the power supply circuit is configured to provide a supply voltage at the output capacitor,

[0015] wherein the control node is also coupled to a first terminal of an auxiliary switch, wherein a second terminal of the auxiliary switch is coupled to a control terminal of the power transistor,

[0016] wherein the auxiliary switch is configured to be turned on only after the supply voltage reaches a predefined level,

[0017] The device further includes another circuit configured to be powered by a supply voltage.

[0018] According to a third aspect, there is provided a device comprising:

[0019] a power transistor comprising a first load terminal, a second load terminal and a control terminal,

[0020] a device control node coupled to the control terminal,

[0021] a power supply circuit coupled to the device control node and comprising at least one output capacitor and at least one diode coupled between the device control node and the output capacitor, wherein the power supply circuit is configured to provide a supply voltage at the output capacitor,

[0022] wherein the control node is also coupled to a first terminal of an auxiliary switch, wherein a second terminal of the auxiliary switch is coupled to a control terminal of the power transistor,

[0023] Therein, the device includes another circuit configured to be powered by a supply voltage and includes a safety circuit configured to detect an error condition associated with the power transistor and to shut down the auxiliary switch in response to detecting the error condition.

[0024] The above summary merely gives an overview of some embodiments and should not be construed as limiting in any way. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a block diagram of a device according to an embodiment.

[0026] Figure 2 is a diagram of a device according to another embodiment.

[0027] Figure 3A and Figure 3B Some example performances are shown.

[0028] Figure 4 is a diagram of a device according to an embodiment.

[0029] Figure 5 is a circuit diagram of a device according to an embodiment.

[0030] Figure 6 It is shown Figure 5 FIG. 1 is a diagram of an exemplary operation of the device.

[0031] Figure 7 is a circuit diagram of a device according to another embodiment.

[0032] Figure 8 is a circuit diagram of a device according to yet another embodiment.

[0033] Fig. 9 It is shown Figure 8 A signal diagram of the operation of an implementation scheme of the present invention. DETAILED DESCRIPTION

[0034] Hereinafter, various embodiments will be described with reference to the accompanying drawings. These embodiments are given by way of example only and should not be construed as limiting.

[0035] Variations and modifications described with respect to one of the embodiments may also be applied to other embodiments and therefore will not be described again. Features such as elements, components, actions, events, circuit components, etc. from various embodiments may be combined to form other embodiments.

[0036] Unless otherwise indicated, connections or couplings shown in the drawings or described herein refer to electrical connections or couplings. Such connections or couplings may be modified, for example, by adding additional elements or modifying elements, as long as the general purpose of the connection or coupling is substantially maintained, for example, to provide voltage or current, transmit signals, provide control, etc. In other words, if a first element is stated to be connected or coupled to a second element, this does not exclude the presence of intermediate elements between the first element and the second element. The expression "directly coupled" or "directly connected" indicates that there are no intermediate elements.

[0037] The transistor used in this article is generally described as including a control terminal and at least two load terminals. In the case of a field effect transistor such as a MOSFET, the control terminal is a gate terminal, and the load terminal includes a source terminal and a drain terminal. There may be, for example, an auxiliary source terminal or an auxiliary drain terminal as another load terminal. In the case of an insulated gate bipolar transistor (IGBT), the control terminal is a gate terminal and the load terminal includes an emitter terminal and a collector terminal. Auxiliary load terminals, such as auxiliary emitter terminals or auxiliary collector terminals, may also be provided herein. In the case of a bipolar junction transistor (BJT), the control terminal is a base terminal, and the load terminal includes a collector terminal and an emitter terminal. Similarly, an auxiliary terminal may be additionally provided. Although field effect transistors are used as examples in some of the embodiments described below, it should be understood that other types of transistors may be used in other embodiments.

[0038] In the drawings, the same elements are denoted by the same reference numerals, and description will not be repeated.

[0039] Figure 1 is a block diagram of a device 10 according to an embodiment. Figure 1 Device 10 is used as a general example for various implementations.

[0040] Figure 1 Device 10 includes a power transistor 12 that, during operation, may be used to switch current and voltage between load terminals thereof in various applications.

[0041] The control terminal of the transistor 12 is coupled to the driver 11. In the following the term gate driver will be used for the driver 11, it being understood that if the corresponding transistor is a bipolar junction transistor the driver is a base driver.

[0042] The control node between the gate driver 11 and the transistor 12 is coupled to a power supply circuit 14. The power supply circuit 14 includes at least one diode 15 (e.g., a plurality of diodes forming a rectifier) ​​and at least one capacitor 16. Based on the voltage output by the gate driver 11 for driving the transistor 12, the power supply circuit 14 generates a power supply voltage V at the capacitor 16. supply to power another circuit 13. In some embodiments, capacitor 16 can be used as an energy storage device for continuously powering another circuit 13 to turn on and off transistor 12 while switching on and off the voltage output by gate driver 11 at regular intervals. Capacitor 16 and capacitors of embodiments further described below can be integrated capacitors, such as integrated with another circuit on a chip die, or external discrete capacitors, such as ceramic capacitors or silicon capacitors, and / or can also include an array of multiple capacitors.

[0043] Another circuit 13 may be a diagnostic and / or monitoring circuit for the power transistor 12. As will be further described below, as indicated by arrow 17A, another circuit 13 may measure a parameter of the power transistor 12, such as a current through the power transistor 12, a temperature associated with the power transistor 12, or a voltage associated with the power transistor 12. Another circuit 13 may be configured to detect an error condition associated with the power transistor 12, such as an overcurrent, an overvoltage, or an overheat. In the event that such an error condition is detected, another circuit 13 may be configured to set the device 10 to a safe state. The safe state of the device 10 means, for example, a state in which the power transistor 12 is protected from damage or destruction due to overcurrent, overvoltage, or overheating.

[0044] As will be further described below, another circuit 13 can open an auxiliary switch to decouple the gate driver 11 from the transistor 12 to set the device 10 to such a safe state. In addition, the other circuit 13 can include an auxiliary gate driver that controls the power transistor 12 to be completely turned off or partially turned off with a certain resistance to mitigate the effects of overcurrent or overvoltage conditions. In some implementations, the other circuit 13 can be a conventional safety circuit that monitors the operation of the transistor 12 and detects an error condition. Arrow 17B shows how the circuit 13 can control the device 10, for example, to set the device 10 to a safe state in response to an error condition.

[0045] In some embodiments, power transistor 12, another circuit 13, and power supply circuit 14 may be integrated in a common package of one or more chip dies. For such a package, in some embodiments, the only terminals may be a control terminal coupled to control node 18 and a terminal coupled to a load terminal of transistor 12, but no other terminals. In some embodiments, this reduces the number of pins used for the package. However, in other embodiments, there may be additional terminals, for example for diagnostic purposes.

[0046] Figure 2 A system 20 according to another embodiment is shown.

[0047] The system 20 includes an insulated gate bipolar transistor with a freewheeling diode as shown as the power transistor 12. Other transistor types such as MOSFETs may also be used.

[0048] The gate terminal of the power transistor 12 is coupled to the gate driver 11. Figure 1 As shown, the power supply circuit 14 is coupled to a control node 18 .

[0049] The power supply circuit 14 supplies power to another circuit 21 which in this case performs current monitoring. For current monitoring, the device 20 includes a sense transistor 23 coupled in parallel to the power transistor 12. The sense transistor is typically a scaled-down version of the power transistor 12, so that the current flowing through the sense transistor 23 is also scaled relative to the current flowing through the power transistor 12. The scaling factor can be large, such as 1:100 or more, so that the largest portion of the current flows through the power transistor 12. However, other scaling factors may be used, or no scaling may be used. Figure 2 As shown in , the sensing transistor 23 is usually controlled by the power transistor 12, that is, the gate terminal of the sensing transistor 23 is also driven by the gate driver 11. For this purpose, a common gate pin can be provided in the package, and the gate driver 11 supplies a control signal to the common gate pin. Then, the control signal is provided to the gate terminals of the sensing transistor 23 and the power transistor 12.

[0050] The current through the sensing transistor 23 is measured by the current measuring device 22. For example, the current measuring device 22 may include a shunt resistor or a magnetic field-based current sensing element, such as a Hall sensor, or a magnetoresistive-based sensor (commonly referred to as an XMR sensor, such as GMR (Giant Magneto-Resistance), TMR (Tunnel Magneto-Resistance), etc.). In other embodiments, the sensing transistor 23 may be omitted, and the current flowing through the power transistor 12 may be measured, for example, at its emitter or auxiliary emitter, using, for example, the above techniques (shunt resistor or magnetic field-based current sensing).

[0051] The further circuit 21 may, for example, compare a measured current indicative of a current through the power transistor 12 with a threshold value. In the event that the current exceeds the threshold value, the further circuit 21 opens an auxiliary switch 24 arranged between the control node 18 and the gate terminal of the power transistor 12. The auxiliary switch 24 in this case may be a normally-on transistor, i.e., a transistor that is in an on state without providing a certain gate voltage, thereby electrically coupling the gate driver 11 to the power transistor 12 (and the auxiliary transistor 23). For example, the auxiliary switch 24 may be implemented as a depletion-type MOSFET. In the event of an error condition, as mentioned above, the auxiliary switch 24 is opened, thereby decoupling the gate driver 11 from the transistors 12, 23, thereby turning them off. In addition, when the auxiliary switch 24 is turned off, the further circuit 21 powered by the power supply circuit 14 may, for example, discharge the gate of the power transistor 12 (and the sense transistor 23, where provided) to its own gate voltage V gate , to set the gate voltage V gate Supplied to the transistors 12, 23 to set them to a defined state, for example a partially on state with increased resistance in the linear region of the transistor.

[0052] Figure 3A and Figure 3B is a timing diagram illustrating the effect of the power supply circuit 14 including the capacitor 16 according to some embodiments. For comparison purposes, Figure 3A and Figure 3B A conventional circuit is shown without the power supply circuit discussed herein.

[0053] Figure 3A and Figure 3B Each of the graphs shows an example gate voltage V of a power transistor (such as power transistor 12). gate , where a high value corresponds to the on state and a low value corresponds to the off state. In addition, Figure 3A and Figure 3B Each of the diagrams shows an exemplary supply voltage V without capacitor 16 with a simple supply from node 18. supply Finally, I C shows the current flowing through the power transistor. OCP Indicates the overcurrent threshold.

[0054] As can be seen, after the gate voltage has reached its high state, the supply voltage V supply Rise slowly.

[0055] Figure 3B shows the case where the power transistor is turned on and after a period of time, the supply voltage V supply After reaching the stable value, a short circuit event occurs. When a short circuit event occurs, the current I C At the rise time t rise It rises rapidly until it exceeds the current threshold I OCP Then, at time t detect Within another circuit (for example, Figure 2 21) detects overcurrent and turns off the power transistor. In this case, the current I C Above the threshold only for a short period of time.

[0056] In contrast, Figure 3A The case where a short circuit event occurs or already exists when the power transistor is turned on is shown. Also in this case, the current rises immediately after turning on the power transistor. However, since the power supply has not yet reached the nominal stable value in this case, another circuit (such as Figure 2 21) has not yet been activated. For this reason, Figure 3B Compared with the case of detect The short circuit is detected later, which means that the high current lasts longer, which may damage the power transistor 12 or other circuit components coupled to the power transistor 12 .

[0057] In contrast, by providing capacitor 16 as an energy storage element, V supply It can also be maintained at a higher value (via stored energy) during the off period of the power transistor 12. This in turn can support earlier detection of overcurrent events (or other events detected by the circuit powered by the power supply circuit, such as overheating or overvoltage), and thus can help reduce the possibility of damage.

[0058] Next, more specific implementations of the power supply circuit and other elements of the device will be discussed.

[0059] Figure 4 4 shows a device 40 according to another embodiment, wherein a supply circuit 44 is shown in more detail. The supply circuit 44 comprises a diode 45. The anode of the diode 45 is coupled to the control node 18, and the cathode of the diode 45 is coupled to a first terminal of an output capacitor 46. A second terminal of the output capacitor 46 is coupled to ground. In the case where the gate driver 11 outputs a positive gate voltage to control the power switch 12, the output capacitor 46 is charged via the diode 45. In this way, a supply voltage V is established across the capacitor 46. supply In the event that the gate driver 11 turns off the power transistor 12, for example by pulling the gate to 0V or a negative voltage, the diode 45 prevents the output capacitor 46 from discharging toward the control node 18 and maintains the supply voltage V supply .

[0060] Then, the voltage V supply Used to power another circuit, such as the one referenced above Figure 1 and Figure 2 By using output capacitor 46, V supply It is also held for a certain time, and so then when the power transistor 12 is switched on again in the presence of a short circuit event, the other circuit can react essentially immediately without a delay as in a conventional power supply circuit without the output capacitor 46 .

[0061] Figure 5 A device 50 according to another embodiment is shown. The device 50 is particularly useful in situations where the gate driver 11 outputs both a positive gate drive voltage and a negative gate drive voltage. For example, in some embodiments, a positive voltage can be used to turn on the power transistor 12, and a negative voltage can be used to turn off the power transistor 12.

[0062] exist Figure 5 In the embodiment, the power supply circuit 54 includes a rectifier coupled to the control node 18 and ground. Figure 5In the case of , a bridge rectifier including four diodes is used. The output of the rectifier 58 charges the input capacitor 59 to the input voltage V input The charge pump 510 then converts the input voltage V input is converted into a voltage for charging the output capacitor 56, wherein a supply voltage V is provided across the output capacitor supply , to power another circuit as discussed above.

[0063] Figure 6 Shows Figure 5 The power supply circuit 54 works. Figure 6 In the example shown, in the on state, a positive gate voltage +V is provided by the gate driver 11. gate , and in the off state provides a gate voltage -V gate An example could be a positive voltage of +15V and a negative voltage of -15V. Figure 6 In the on state, the absolute values ​​of the positive gate voltage and the negative gate voltage are the same, but in other embodiments, these values ​​may be different. input Corresponding to V gate , and converted into V by charge pump 510 supply In the off state, V input has the same polarity as the on state (due to the rectifier), but exhibits a common-mode shift compared to the on state. In both cases, V input is converted into the same supply voltage V by the charge pump 510 supply To charge the output capacitor 56 .

[0064] It should be noted that in some embodiments, input capacitor 59 may be omitted and the output of rectifier 58 may be provided directly to charge pump 510 .

[0065] Figure 7 It shows that basically Figure 4 and Figure 5 In addition to the path for charging the output capacitor 56 through the rectifier 58, the input capacitor 59 and the charge pump 510, a method is also provided as follows: Figure 4 The diode 45 in the gate driver 11 is bypassed so that the output capacitor 56 is charged directly from the control node 18 through the diode 45 when the voltage output by the gate driver 11 is positive. This bypassing through the diode 45 can allow faster charging in some implementations when the voltage output by the gate driver is positive.

[0066] Figure 8 A device 70 according to another embodiment is shown. Figure 4 The power supply circuit 44 is used as Figure 8 However, alternatively, it is also possible to use Figure 5 The power supply circuit 54 or Figure 7 The power supply circuit 64.

[0067] Figure 8 The embodiment further includes a switching device 73, the switching device 73 including an auxiliary switch 71 between the gate driver 11 and the power transistor 12. The auxiliary switch 71 may be a transistor switch. Figure 2 Unlike the auxiliary switch 24 of FIG. 1 , the auxiliary switch 71 may be a normally closed switch that disconnects the driver circuit 11 from the power transistor 12 unless a corresponding control signal is applied to the auxiliary switch 71 . supply Below a threshold (e.g. Figure 3A and Figure 3B The auxiliary switch 71 is turned on only when the supply voltage V supply When the power supply voltage V is high enough to supply power to the other circuit 72, the other circuit 72 becomes operable and can act on the switching device 73 to turn off the auxiliary switch 71. Then, the power switch 12 is turned on by the gate drive voltage transmitted by the gate driver 11. supply In addition to the function of switching on the auxiliary switch 71 when the voltage is high enough, the further circuit 72 may also include a safety circuit that monitors the power transistor 12 as discussed above.

[0068] By closing the auxiliary switch 71 only after the power supply reaches a certain level, in some embodiments, this can prevent Figure 3A The situation may be, for example, at the first switch-on at startup or after a longer switch-off period, wherein a corresponding output capacitor, such as output capacitor 46, is discharged.

[0069] It should be noted that the auxiliary switch 71 is turned on when the power transistor is to be turned off (because it was previously turned on), or may include a body diode or a separate diode that is always allowed to conduct to turn off the power transistor 12.

[0070] It should be noted that the auxiliary switch 71 may also have Figure 2 The auxiliary switch 24 of FIG. 1 can be used to open the auxiliary switch 71 when an error condition is detected. In other embodiments, separate auxiliary switches can be provided for these two functions (on the one hand, as long as V supply If the threshold value has not yet been exceeded, the driver circuit 11 is disconnected from the power transistor 12, and on the other hand, in the event of an error condition, the driver circuit 11 is disconnected from the power transistor 12).

[0071] Fig. 9It is shown Figure 8 A signal diagram of the operation of an implementation scheme of the present invention.

[0072] In time period 1, starting at t1, device 70 is turned off. Then, at time t2 starting at time period 2, gate driver 11 outputs positive voltage Vdriver. supply After a certain time of establishing and supplying the power required by the other circuit 72, at the end of the time period 2 marked by the dotted line 80, at the time t3 when the supply voltage Vsupply exceeds the threshold voltage Vthres, the auxiliary switch 71 is closed, the gate voltage Vgate at the power transistor 12 increases, and the power transistor 2 is turned on. Therefore, the auxiliary switch 71 introduces a delay when it is turned on for the first time.

[0073] At the end of period 3, Vdriver becomes zero at time t4 and power transistor 12 is switched off. However, due to capacitor 46, voltage Vsupply drops only very slowly and reaches almost nominal value at the next switching event at the end of period 4 at time t5.

[0074] Since the supply voltage is already high (and above the threshold) when the gate driver 11 provides the high drive voltage, the auxiliary switch 71 is already turned on, so that the gate driver output voltage is almost immediately applied to the gate of the transistor 12 at the dashed line 81 .

[0075] It should be noted that the gate driver 11 may output the gate voltage through a gate driver resistor, which is conventional for such devices.

[0076] Some embodiments are defined by the following examples:

[0077] Example 1. A device comprising:

[0078] a power transistor comprising a first load terminal, a second load terminal and a control terminal,

[0079] a device control node coupled to the control terminal,

[0080] A power supply circuit, coupled to a device control node, comprising:

[0081] a rectifier arrangement coupled between the device control node and the input side of the charge pump, and

[0082] Wherein, the output side of the charge pump is coupled to the output capacitor,

[0083] Therein, a power supply circuit is configured to provide a supply voltage at an output capacitor, and another circuit is configured to be powered by the supply voltage.

[0084] Example 2. The device of Example 1, wherein the control node is further coupled to a first terminal of an auxiliary switch, wherein a second terminal of the auxiliary switch is coupled to a control terminal of the power transistor.

[0085] Example 3. The device of Example 2, wherein the auxiliary switch is configured to be in an off state until the supply voltage is greater than or equal to a predefined threshold voltage.

[0086] Example 4. The device of Example 2 or 3, wherein the auxiliary switch comprises a normally closed switch.

[0087] Example 5. A device according to Example 3 or 4, wherein the auxiliary switch includes a control terminal and is configured to switch between an on state and an off state based on a control voltage applied to its control terminal, and wherein another circuit is configured to control the switching state of the auxiliary switch based on a supply voltage.

[0088] Example 6. The device of any of Examples 1 to 5, wherein the further circuit is configured to monitor at least one operating state of the power transistor.

[0089] Example 7. The device of any of Examples 1 to 6, wherein the further circuit comprises a safety circuit configured to detect an error condition associated with the power transistor and to set the device to a safe state in response to detecting the error condition.

[0090] Example 8. The device of any of Examples 7 and 2 or 3, wherein the further circuit is configured to turn off the auxiliary switch in response to detecting the error condition.

[0091] Example 9. The device of Example 8, wherein the auxiliary switch is a normally open switch.

[0092] Example 10. The device of any of Examples 1 to 9, wherein the further circuit comprises at least one of:

[0093] - a temperature sensing circuit for sensing the temperature of the power transistor;

[0094] - a current sensing circuit for sensing the current through the power transistor;

[0095] - a voltage sensing circuit for sensing the voltage at the power transistor; or

[0096] - A driver circuit for driving a transistor of another circuit.

[0097] Example 11. A device according to any one of Examples 1 to 10, wherein the device is arranged in a package, wherein the only terminals of the package are, at most, a first package terminal coupled to a device control node, a second device terminal coupled to a first load terminal of a power transistor, and a third device terminal and a fourth device terminal coupled to a second load terminal of the power transistor.

[0098] Example 12. The device of any of Examples 1 to 11, wherein the charge pump is configured to charge the output capacitor to provide the supply voltage for both positive and negative voltages at the control node.

[0099] Example 13. The device of any of Examples 1 to 12, further comprising a driver circuit coupled to the device control node and configured to drive the power transistor.

[0100] Example 14. The device of Example 13, wherein the driver circuit includes a gate resistor.

[0101] Example 15. The device of Example 13 or 14, wherein the driver circuit is configured to selectively provide a positive voltage or a negative voltage for driving the power transistor.

[0102] Example 16. The device of any of Examples 1 to 15, further comprising an input capacitor coupled between the rectifier and the charge pump.

[0103] Example 17. The device of any of Examples 1 to 16, further comprising a diode, wherein an anode of the diode is coupled to the control node and a cathode of the diode is coupled to a terminal of the output capacitor.

[0104] Example 18. A device comprising:

[0105] a power transistor comprising a first load terminal, a second load terminal and a control terminal,

[0106] a device control node coupled to the control terminal,

[0107] a power supply circuit coupled to the device control node and comprising at least one output capacitor and at least one diode coupled between the device control node and the output capacitor, wherein the power supply circuit is configured to provide a supply voltage at the output capacitor,

[0108] wherein the control node is also coupled to a first terminal of an auxiliary switch, wherein a second terminal of the auxiliary switch is coupled to a control terminal of the power transistor,

[0109] wherein the auxiliary switch is configured to be in an off state until the supply voltage is greater than or equal to a predefined threshold voltage,

[0110] The device also includes

[0111] Another circuit is configured to be powered by the supply voltage.

[0112] Example 19. A device according to Example 18, wherein the auxiliary switch includes a control terminal and is configured to switch between an on state and an off state based on a control voltage applied to its control terminal, and wherein another circuit is configured to control the switching state of the auxiliary switch based on a supply voltage.

[0113] Example 20. The device of Example 18 or 19, wherein the at least one diode comprises a first diode, wherein a cathode of the first diode is coupled to a terminal of the output capacitor.

[0114] Example 21. The device of any of Examples 18 to 20, wherein the auxiliary switch comprises a normally closed switch.

[0115] Example 22. The device of any of Examples 18 to 21, wherein the further circuit is configured to monitor at least one operating state of the power transistor.

[0116] Example 23. The device of any of Examples 18 to 22, wherein the further circuit comprises a safety circuit configured to detect an error condition associated with the power transistor and to set the device to a safe state in response to detecting the error condition.

[0117] Example 24. The device of Example 23, wherein the further circuit is configured to turn off the auxiliary switch in response to detecting the error condition.

[0118] Example 25. The device of any of Examples 18 to 24, wherein the other circuit comprises at least one of:

[0119] - a temperature sensing circuit for sensing the temperature of the power transistor;

[0120] - a current sensing circuit for sensing the current through the power transistor;

[0121] - a voltage sensing circuit for sensing the voltage at the power transistor; or

[0122] - A driver circuit for driving a transistor of another circuit.

[0123] Example 26. A device according to any one of Examples 18 to 25, wherein the device is provided in a package wherein the only terminals of the package are, at most, a first package terminal coupled to a device control node, a second device terminal coupled to a first load terminal of a power transistor, and third and fourth device terminals coupled to a second load terminal of the power transistor.

[0124] Example 27. The device of any of Examples 18 to 26, further comprising a driver circuit coupled to the device control node and configured to drive the power transistor.

[0125] Example 28. The device of Example 27, wherein the driver circuit comprises a gate resistor.

[0126] Example 29. A device comprising:

[0127] a power transistor comprising a first load terminal, a second load terminal and a control terminal,

[0128] a device control node coupled to the control terminal,

[0129] a power supply circuit coupled to the device control node and comprising at least one output capacitor and at least one diode coupled between the device control node and the output capacitor, wherein the power supply circuit is configured to provide a supply voltage at the output capacitor,

[0130] wherein the control node is also coupled to a first terminal of an auxiliary switch, wherein a second terminal of the auxiliary switch is coupled to a control terminal of the power transistor,

[0131] wherein the device comprises another circuit configured to be powered by a supply voltage,

[0132] Therein, another circuit includes a safety circuit configured to detect an error condition associated with the power transistor and to shut off the auxiliary switch in response to detecting the error condition.

[0133] Example 30. The device of Example 29, wherein the further circuit is further configured to supply a control voltage to a control terminal of the power transistor after turning off the auxiliary switch.

[0134] Example 31. The device of Example 29 or 30, wherein the at least one diode comprises a first diode, wherein a cathode of the first diode is coupled to a terminal of the output capacitor.

[0135] Embodiment 32. The device of any of Examples 29 to 31, wherein the auxiliary switch comprises a normally open switch.

[0136] Example 33. The device of any of Examples 29 to 32, wherein the further circuit comprises at least one of:

[0137] - a temperature sensing circuit for sensing the temperature of the power transistor;

[0138] - a current sensing circuit for sensing the current through the power transistor;

[0139] - a voltage sensing circuit for sensing the voltage at the power transistor; or

[0140] - A driver circuit for driving a transistor of another circuit.

[0141] Example 34. A device according to any one of Examples 29 to 33, wherein the device is provided in a package wherein the only terminals of the package are, at most, a first package terminal coupled to a device control node, a second device terminal coupled to a first load terminal of a power transistor, and third and fourth device terminals coupled to a second load terminal of the power transistor.

[0142] Example 35. The device of any of Examples 29 to 34, further comprising a driver circuit coupled to the device control node and configured to drive the power transistor.

[0143] Example 36. The device of Example 35, wherein the driver circuit comprises a gate resistor.

[0144] Although specific embodiments have been shown and described herein, it will be appreciated by those skilled in the art that various alternatives and / or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the invention. This application is intended to cover any adaptation or variation of the specific embodiments discussed herein. Therefore, the present invention is limited only by the claims and their equivalents.

Claims

1. A device (10, 20, 40, 50, 60, 70) comprising a power transistor, comprising: The power transistor (12) comprises a first load terminal, a second load terminal and a control terminal, a device control node (18) coupled to the control terminal, A power supply circuit (14, 44, 54, 64) coupled to the device control node (18) and comprising: a rectifier (58) coupled between the device control node (18) and an input side of a charge pump (510), The output side of the charge pump (510) is coupled to the output capacitor (16, 46, 56), and wherein the power supply circuit (14, 44, 54, 64) is configured to provide a supply voltage at the output capacitor (16, 46, 56), and Another circuit (13, 72) is configured to be powered by the supply voltage.

2. The device (10, 20, 40, 50, 60, 70) according to claim 1, wherein The device control node (18) is also coupled to a first terminal of an auxiliary switch (71), wherein a second terminal of the auxiliary switch (71) is coupled to a control terminal of the power transistor (12).

3. The device (10, 20, 40, 50, 60, 70) according to claim 2, wherein The auxiliary switch (71) comprises a control terminal and is configured to switch between an on state and an off state based on a control voltage applied to the control terminal thereof, and wherein the further circuit (72) is configured to control the switching state of the auxiliary switch (71) based on the supply voltage.

4. The device according to any one of claims 1 to 3, wherein The charge pump (510) is configured to charge the output capacitor (56) to provide the supply voltage for both positive and negative voltages at the device control node (18).

5. The device (10, 20, 40, 50, 60, 70) according to any one of claims 1 to 4, further comprising a driver circuit (11) coupled to the device control node (18) and configured to drive the power transistor (12).

6. The device according to claim 5, wherein The driver circuit (11) is configured to selectively provide a positive voltage or a negative voltage for driving the power transistor (12).

7. The device (10, 20, 40, 50, 60, 70) according to any one of claims 1 to 6, further comprising an input capacitor (59) coupled between the rectifier (58) and the charge pump (510).

8. The device (10, 20, 40, 50, 60, 70) according to any one of claims 1 to 7, further comprising a diode (45), wherein The anode of the diode (45) is coupled to the device control node (18), and the cathode of the diode (45) is coupled to a terminal of the output capacitor (16, 46, 56).

9. A device (10, 20, 40, 50, 60, 70) comprising a power transistor, comprising: The power transistor (12) comprises a first load terminal, a second load terminal and a control terminal, a device control node (18) coupled to the control terminal, A power supply circuit (14, 44, 54, 64) coupled to the device control node (18) and comprising at least one output capacitor (16, 46, 56) and at least one diode (15, 45, 58) coupled between the device control node (18) and the output capacitor (16, 46, 56), wherein the power supply circuit (14, 44, 54, 64) is configured to provide a supply voltage at the output capacitor (16, 46, 56), wherein the device control node (18) is also coupled to a first terminal of an auxiliary switch (71), wherein a second terminal of the auxiliary switch (71) is coupled to a control terminal of the power transistor (12), wherein the auxiliary switch (71) is configured to be in an off state until the supply voltage is greater than or equal to a predetermined threshold voltage, Wherein, the device (10, 20, 40, 50, 60, 70) also includes Another circuit (13, 72) is configured to be powered by the supply voltage.

10. The device (10, 20, 40, 50, 60, 70) according to claim 9, wherein The auxiliary switch (71) comprises a control terminal and is configured to switch between an on state and an off state based on a control voltage applied to the control terminal thereof, and wherein the further circuit (72) is configured to control the switching state of the auxiliary switch (71) based on the supply voltage.

11. The device (10, 20, 40, 50, 60, 70) according to any one of claims 1 to 10, wherein The further circuit (13) includes a safety circuit configured to detect an error condition associated with the power transistor (12) and to set the device (10, 20, 40, 50, 60, 70) to a safe state in response to detecting the error condition.

12. The device (10, 20, 40, 50, 60, 70) according to claim 11, wherein The further circuit (13) is configured to switch off the auxiliary switch (71) in response to detecting the error condition.

13. A device (10, 20, 40, 50, 60, 70) comprising a power transistor, comprising: The power transistor (12) comprises a first load terminal, a second load terminal and a control terminal, a device control node (18) coupled to the control terminal, A power supply circuit (14, 44, 54, 64) coupled to the device control node (18) and comprising at least one output capacitor (16, 46, 56) and at least one diode (15, 45, 58) coupled between the device controller (18) and the output capacitor (16, 46, 56), wherein the power supply circuit (14, 44, 54, 64) is configured to provide a supply voltage at the output capacitor (16, 46, 56), wherein the device control node (18) is also coupled to a first terminal of an auxiliary switch (71), wherein a second terminal of the auxiliary switch (71) is coupled to a control terminal of the power transistor (12), wherein the device (10, 20, 40, 50, 60, 70) comprises a further circuit (13, 72) configured to be powered by the supply voltage, The further circuit (13) comprises a safety circuit configured to detect an error condition associated with the power transistor (12) and to turn off the auxiliary switch (71) in response to detecting the error condition.

14. The device (10, 20, 40, 50, 60, 70) according to claim 13, wherein The further circuit is further configured to supply a control voltage to a control terminal of the power transistor (12) after the auxiliary switch (71) is turned off.

15. The device (10, 20, 40, 50, 60, 70) according to any one of claims 1 to 14, wherein The device is arranged in a package, wherein the only terminals of the package include at most a first package terminal coupled to the device control node (18), a second device terminal coupled to a first load terminal of the power transistor (12), and third and fourth device terminals coupled to the second load terminal of the power transistor (12).

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