Voltage screening device and equipment based on power switch tube

Abstract

The utility model provides a voltage screening device and equipment based on a power switch tube. A voltage screening apparatus is characterized by comprising: a voltage screening module configured to provide a driving voltage based on an input voltage; and the logic control module is configured to control the voltage screening module to enable the driving voltage to be within a preset range.

Description

Technical Field

[0001] The present application relates to the field of circuit technology, and more particularly, to a voltage screening device and a device based on a power switching diode. Background Art

[0002] Power switching diodes (such as power metal-oxide-semiconductor field-effect transistors (MOSFETs)) are typically used as three-phase bridge switches to drive induction motors (such as permanent magnet synchronous motors (PMSMs)). The power MOSFET's conduction condition requires that the voltage difference (Vgs) between the gate and source voltages is greater than the turn-on threshold voltage. Furthermore, the voltage difference (Vgs) between the gate and source voltages should not be too large. If it exceeds the maximum tolerance (Vgs_max), it will potentially cause failure of the power MOSFET. Typically, the voltage difference (Vgs) between the gate and source voltages should be within the range of -20V ≤ Vgs ≤ 20V.

[0003] For source-grounded applications, when the minimum gate input voltage Vin is less than Vgs_max but its maximum is greater than Vgs_max (e.g., 3.3V≤Vin≤40V, Vgs_max=20V), in order to ensure that Vin can drive the power MOSFET without generating overvoltage stress, a targeted circuit needs to be designed to meet the requirements. Utility Model Content

[0004] In one aspect, an embodiment of the present application provides a voltage screening device, characterized in that it includes: a voltage screening module, configured to provide a driving voltage based on an input voltage; and a logic control module, configured to control the voltage screening module so that the driving voltage is within a predetermined range.

[0005] In some implementations, the voltage screening module includes: a voltage comparator configured to provide an output voltage based on a comparison between an input voltage and a first reference voltage; a voltage divider configured to provide a divided voltage based on the input voltage; a voltage follower configured to provide a following voltage based on the divided voltage; and a first switching tube configured to be turned off or turned on according to the control of the logic control module so that the output voltage or the following voltage is used as a driving voltage.

[0006] In some implementations, the voltage comparator has a non-inverting input terminal, an inverting input terminal, and an output terminal, wherein the non-inverting input terminal is used to receive a first reference voltage, the inverting input terminal is used to receive an input voltage, and the output terminal is used to provide an output voltage.

[0007] In some implementations, the voltage divider includes: a second resistor and a third resistor, the first end of the second resistor is used to receive an input voltage, the second end of the second resistor is connected to the first end of the third resistor, the second end of the third resistor is grounded, and the connection point between the second end of the second resistor and the first end of the third resistor is used to provide a divided voltage.

[0008] In some implementations, the voltage follower has a non-inverting input terminal, an inverting input terminal, and an output terminal, the non-inverting input terminal is connected to the connection point of the second end of the second resistor and the first end of the third resistor in the voltage divider to receive the divided voltage, the inverting input terminal is connected to the output terminal, and the output terminal is connected to the first switching tube.

[0009] In some implementations, the first switching tube has an emitter, a collector, and a base. The emitter is connected to the output of the voltage follower and to the logic control module via a fourth resistor. The collector is connected to the output of the voltage comparator via a fifth resistor and to ground via a first capacitor and serves as the output of the voltage screening device. The base is connected to the logic control module.

[0010] In some implementations, the logic control module is configured to control the first switch to be turned off or on based on the output voltage.

[0011] In some implementations, the logic control module is configured to: control the first switch tube to be turned off when the output voltage is at a high level; and control the first switch tube to be turned on when the output voltage is at a low level.

[0012] In some implementations, the logic control module includes: a second switch tube, the base of the second switch tube is connected to the output end of the voltage comparator of the voltage screening module via a sixth resistor and is grounded via a seventh resistor, the emitter of the second switch tube is grounded, and the collector of the second switch tube receives the second reference voltage via an eighth resistor; and a third switch tube, the base of the third switch tube is connected to the collector of the second switch tube via a ninth resistor R9 and is grounded via a tenth resistor, the emitter of the third switch tube is grounded, and the collector of the third switch tube is connected to the base of the first switch of the voltage screening module via an eleventh resistor.

[0013] In some implementations, the logic control module includes: an eleventh resistor, a first end of the eleventh resistor is connected to the base of the first switch tube of the voltage screening module, and a second end of the eleventh resistor is connected to the output end of the voltage comparator of the voltage screening module.

[0014] In one aspect, an embodiment of the present application provides a device based on a power switch tube, characterized in that it includes: a power switch tube; and any voltage screening device according to an embodiment of the present application, used to provide a driving voltage for the power switch tube.

[0015] According to the voltage screening device and the power switch tube-based equipment according to the embodiments of the present application, it can be ensured that the driving voltage provided to the power diode not only meets the driving conditions of the power switch tube, but also does not cause overvoltage stress to the power tube, thereby being suitable for achieving safe and reliable operation within the full input voltage range. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly describes the drawings involved in the embodiments of the present application. It should be understood that according to practical practices, these drawings are not necessarily drawn to scale and can be adjusted according to actual needs. In the drawings:

[0017] Figure 1 is a block diagram of a device based on a power switch tube according to an embodiment of the present application;

[0018] Figure 2 is a circuit diagram of an example of a device based on a power switch tube according to an embodiment of the present application;

[0019] Figure 3 is a circuit diagram of another example of a device based on a power switch tube according to an embodiment of the present application;

[0020] Figure 4 A waveform diagram showing the influence of an input voltage on an output voltage of a voltage comparator according to an embodiment of the present application is shown;

[0021] Figure 5 A schematic diagram of the waveforms of the driving voltage and the load current of the power switch tube according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0022] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, scheme, and advantages of the present application clearer, the details of the present application are further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. For those skilled in the art, the present application can be implemented without some of the details in these specific details. The following description of the embodiments is only for providing a better understanding of the present application by illustrating the examples of the present application.

[0023] It should be noted that, in this article, relational terms such as first, second, third, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. In addition, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, and the process, method, article or equipment including a series of elements includes not only these elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the presence of additional elements in the process, method, article or equipment including the elements.

[0024] Figure 1 FIG is a block diagram of a device based on a power switching diode according to an embodiment of the present application. Figure 1 As shown, the power switch diode-based device 100 according to an embodiment of the present application includes: a power switch tube 101 and a voltage screening device 102 .

[0025] The power switch tube 101 may be, for example, a power metal oxide semiconductor field effect transistor (MOSFET), which is usually used as a three-phase bridge arm switch to drive an induction motor (not shown in the figure).

[0026] The voltage screening device 102 includes: a voltage screening module 1021, configured to provide a driving voltage Vdrive based on the input voltage Vin; and a logic control module 1022, configured to control the voltage screening module 1021 so that the driving voltage Vdrive is within a predetermined range (for example, within the acceptable input voltage range of the power switch tube 101).

[0027] According to the power switch tube-based device of the embodiment of the present application, it can ensure that the driving voltage provided to the power switch tube not only meets the driving conditions of the power switch tube, but also does not cause overvoltage stress on the power tube, thereby being suitable for achieving safe and reliable operation within the full input voltage range.

[0028] Figure 2 FIG is a circuit diagram of a device based on a power switching diode according to an embodiment of the present application. Figure 2 As shown, the power switch diode-based device 200 according to an embodiment of the present application includes: a power switch tube 201 and a voltage screening device 202 .

[0029] Power switch 201 includes a MOSFET T1 (having a body diode D) and a first resistor R1. The gate of MOSFET T1 is connected to voltage screening device 202, the source of MOSFET T1 is grounded, and the drain of MOSFET T1 is connected to a first terminal of first resistor R1. The second terminal of first resistor R1 is connected to other components of device 200 (e.g., an induction motor, not shown).

[0030] The voltage screening device 202 includes a voltage screening module 2021 configured to provide a drive voltage Vdrive based on an input voltage Vin; and a logic control module 2022 configured to control the voltage screening module 2021 so that the drive voltage Vdrive is within a predetermined range (e.g., an acceptable input voltage range of the power switch 201). As an example, the input voltage Vin has an initial minimum value of 3.3V, a maximum value of 40V, a rise time and a fall time of 150ms, and a maximum hold time of 200ms.

[0031] like Figure 2 As shown, the voltage screening module 2021 includes: a voltage comparator U1, configured to provide an output voltage Vo based on a comparison of an input voltage Vin and a first reference voltage Vref1 (for example, 12V); a voltage divider Div, configured to provide a divided voltage Vdiv based on the input voltage Vin; a voltage follower U2, configured to provide a following voltage Vfol based on the divided voltage Vdiv; and a first switch tube Q1, configured to be turned off or turned on according to the control of the logic control module 2022, so that the output voltage Vo or the following voltage Vfol is used as the driving voltage Vdrive.

[0032] like Figure 2 As shown, the voltage comparator U1 has a non-inverting input terminal, an inverting input terminal and an output terminal, wherein the non-inverting input terminal is used to receive the first reference voltage Vref1, the inverting input terminal is used to receive the input voltage Vin, and the output terminal is used to provide the output voltage Vo.

[0033] like Figure 2 As shown, the voltage divider Dive includes: a second resistor R2 and a third resistor R3, the first end of the second resistor R2 is used to receive the input voltage Vin, the second end of the second resistor R2 is connected to the first end of the third resistor R3, the second end of the third resistor R3 is grounded, and the connection point between the second end of the second resistor R2 and the first end of the third resistor R3 is used to provide a divided voltage Vdiv.

[0034] like Figure 2As shown, the voltage follower U2 has a non-inverting input terminal, an inverting input terminal and an output terminal. The non-inverting input terminal is connected to the connection point of the second end of the second resistor R2 and the first end of the third resistor R3 in the voltage divider Div to receive the divided voltage Vdiv, the inverting input terminal is connected to the output terminal, and the output terminal is connected to the first switch tube Q1.

[0035] like Figure 2 As shown, the first switch Q1 has an emitter, a collector, and a base. The emitter is connected to the output of the voltage follower U2 and is connected to the logic control module 303 via the fourth resistor R4. The collector is connected to the output of the voltage comparator U1 via the fifth resistor R5 and is grounded via the first capacitor C1 and serves as the output of the voltage screening device 200. The base is connected to the logic control module 202. In some implementations, the first switch Q1 can be a PNP transistor.

[0036] In the embodiment of the present application, the fourth resistor R4 is a stabilizing resistor for stabilizing the voltage difference between the base and the emitter of the first switch tube Q1 , and the first capacitor C1 is a filter capacitor for the drive voltage Vdrive.

[0037] like Figure 2 As shown, the logic control module 202 is configured to control the turning off or on of the first switch tube Q1 based on the output voltage Vo.

[0038] like Figure 2 As shown, the logic control module 202 is configured to: control the first switch tube Q1 to be turned off when the output voltage Vo is at a high level; and control the first switch tube Q1 to be turned on when the output voltage Vo is at a low level.

[0039] In some implementations, such as Figure 2 As shown, the logic control module 202 includes: a second switch transistor Q2, the base of which is connected to the output terminal of the voltage comparator U1 of the voltage screening module 201 via a sixth resistor R6 and grounded via a seventh resistor R7, the emitter of which is grounded, and the collector of which receives the second reference voltage Vref2 via an eighth resistor R8; and a third switch transistor Q3, the base of which is connected to the collector of the second switch transistor Q2 via a ninth resistor R9 and grounded via a tenth resistor R10, the emitter of which is grounded, and the collector of which is connected to the base of the first switch Q1 of the voltage screening module 201 via an eleventh resistor R11. In some implementations, the second switch transistor Q2 may be an NPN transistor.

[0040] In the embodiment of the present application, the sixth resistor R6 is a current-limiting resistor, the seventh resistor R7 is a pull-down resistor for the second switch tube Q2, and the eighth resistor R8 is a pull-up resistor for the second switch tube Q2 (for example, pulled up to 5V); the ninth resistor R9 is a current-limiting resistor, the tenth resistor R10 is a pull-down resistor for the third switch tube Q3, and the eleventh resistor R11 is a current-limiting resistor.

[0041] like Figure 2 As shown, the second reference voltage is lower than the first reference voltage, for example, 5V.

[0042] The following briefly introduces the operating principle of the power switch tube-based device according to the embodiment of the present application to achieve the voltage screening function.

[0043] When the input voltage Vin is lower than the first reference voltage Vref (e.g., 12V), the output voltage Vo provided by the voltage comparator U1 is approximately 12V. At this time, the second switch tube Q2 is turned on. At this time, the input terminal on the left side of the ninth resistor R9 is at a low level of approximately 0V, and the third switch tube Q3 is turned off. As a result, the first switch tube Q1 is turned off. Therefore, the follower voltage Vfol output by the voltage follower U2 cannot converge to the driving voltage Vgate in the off state. At this time, the driving voltage Vgate is equal to the output voltage Vo provided by the voltage comparator U1, that is:

[0044] Vgate≈12V

[0045] When the input voltage Vin is greater than or equal to the first reference voltage Vref (e.g., 12V), the output voltage Vo provided by the voltage comparator U1 is approximately 0V. At this time, the second switch Q3 is not conducting. At this time, the input terminal on the left side of the ninth resistor R9 is pulled up to a high level by the pull-up eighth resistor R8, and the third switch Q3 is turned on. At this time, the eleventh resistor R11 is pulled down to ground, and the first switch Q1 is turned on. Therefore, the follower voltage Vfol output from the voltage follower U2 after the voltage divider effect of the second resistor R2 and the third resistor R3 can converge to the drive voltage Vgate in the conduction state. Due to the presence of the fifth resistor R5, the drive voltage Vgate and the output voltage Vo provided by the voltage comparator U1 do not affect each other. Therefore, the drive voltage Vgate is approximately the voltage after the input voltage Vin is divided, that is:

[0046]

[0047] The above description applies to the case where the input voltage Vin changes from a minimum value to a maximum value. Similarly, the above analysis also holds true when the input voltage Vin changes from a maximum value to a minimum value. Therefore, the drive voltage Vgate provided by the voltage screening device according to the embodiment of the present application is maintained within a predetermined range, satisfying the driving conditions of the power switch without causing overvoltage stress on the power switch, thereby achieving safe and reliable operation over the full input voltage range.

[0048] The above describes the implementation of the device based on the power switch tube according to some embodiments. The present application is not limited to the above. In some embodiments, for example, only the eleventh resistor R11 can be used to implement the logic control module. For details, see Figure 3 And the following detailed description.

[0049] Figure 3 FIG. 1 is a circuit diagram of another example of a device based on a switching diode according to an embodiment of the present application. Figure 3 As shown, the switching diode-based device 300 according to an embodiment of the present application includes: a power switch tube 301 and a voltage screening device 302 .

[0050] The structure of the power switch tube 301 is Figure 2 The structure of the power switch tube 201 shown in FIG is the same as that of FIG, and will not be repeated here.

[0051] The voltage screening device 302 includes: a voltage screening module 3021, configured to provide a driving voltage Vgate based on the input voltage Vin; and a logic control module 3023, configured to control the voltage screening module 3021 so that the driving voltage Vgate is within a predetermined range (for example, within the acceptable input voltage range of the power switch tube 301).

[0052] The structure and Figure 2 The structure of the voltage screening module 2021 shown in FIG is the same as that of FIG, and will not be repeated here.

[0053] like Figure 3 As shown, the logic control module 3022 includes: an eleventh resistor R11, a first end of the eleventh resistor R11 is connected to the base of the first switch tube Q1 of the voltage screening module 3021, and a second end of the eleventh resistor is connected to the output end of the voltage comparator U1 of the voltage screening module 3021.

[0054] Figure 3 The device 300 based on the power switch tube can realize the operation principle of the voltage screening function. Figure 2 The operating principle of the power switch tube-based device 200 is similar.

[0055] When the input voltage Vin is lower than the first reference voltage Vref (e.g., 12V), the output voltage Vo provided by the voltage comparator U1 is approximately 12V. At this time, the source voltage of the first switching tube Q1 is lower than the base voltage, so the first switching tube Q1 is not turned on. Therefore, the follower voltage Vfol output by the voltage follower U2 cannot converge to the driving voltage Vgate in the off state. At this time, the driving voltage Vgate is equal to the output voltage Vo provided by the voltage comparator U1, that is:

[0056] Vgate≈12V

[0057] When the input voltage Vin is greater than or equal to the first reference voltage Vref (e.g., 12V), the output voltage Vo provided by the voltage comparator U1 is approximately 0V. At this time, the source voltage of the first switch tube Q1 is higher than the base voltage of the first switch tube Q1, so the first switch tube Q1 is turned on. Therefore, the follower voltage Vfol output from the voltage follower U2 can converge to the drive voltage Vgate in the on state after the voltage division effect of the second resistor R2 and the third resistor R3. Due to the presence of the fifth resistor R5, the drive voltage Vgate and the output voltage Vo provided by the voltage comparator U1 do not affect each other. Therefore, the drive voltage Vgate is approximately the voltage after the input voltage Vin is divided, that is:

[0058]

[0059] Similarly, the above description applies to the case where the input voltage Vin changes from a minimum value to a maximum value. Similarly, the above analysis also holds true when the input voltage Vin changes from a maximum value to a minimum value. Therefore, the drive voltage Vgate provided by the voltage screening device according to the embodiment of the present application is maintained within a predetermined range, satisfying the driving conditions of the power switch tube without causing overvoltage stress on the power tube, thereby achieving safe and reliable operation over the full input voltage range.

[0060] In order to verify the safe and reliable operation capability of the voltage screening device within the full input voltage range, the changes of each signal are accurately observed through simulation waveforms. Figure 4 A waveform diagram showing the influence of the input voltage Vin on the output voltage Vo of the voltage comparator according to an embodiment of the present application is shown; Figure 5 A schematic diagram of the waveforms of the driving voltage Vgate and the load current Id of the power switch tube according to an embodiment of the present application is shown.

[0061] like Figure 4 As shown, still using the example mentioned above, the initial minimum value of the input voltage Vin is 3.3V, the maximum value is 40V, the rise time and fall time are 150ms, and the maximum hold time is 200ms. When the input voltage Vin is less than 12V, the output voltage Vo is 12V. Accordingly, Figure 5 As shown, the driving voltage Vgate is about 12V; when the input voltage Vin is greater than or equal to 12V, the output voltage Vo is about 0V. Accordingly, Figure 5 As shown, the driving voltage Vgate is within a certain range of less than 12V. The load current Id of the power switch tube remains unchanged throughout the entire input voltage range. The above simulation shows that when the withstand voltage of the power switch tube is within the minimum and maximum values ​​of the input voltage Vin, the device according to the embodiment of the present application can achieve safe and reliable operation within the entire input voltage range.

[0062] It should be understood that the above description provides some specific numerical examples, but the present application is not limited thereto. By adjusting the above numerical values, voltage screening within different input voltage ranges can be achieved.

[0063] Those skilled in the art will understand that the present application is not limited to the specific structures and steps described above and shown in the accompanying drawings. For the sake of simplicity, the description of known structures and methods is omitted herein. In the above embodiments, several specific steps are described and shown as examples. However, the method of the present application is not limited to the specific steps described and shown. Without departing from the scope of the present application, those skilled in the art can make various changes, modifications and additions to the embodiments of the present application, or change the order between the steps.

[0064] The above disclosures are only some specific implementation methods of the present application. Those skilled in the art will understand that the scope of protection of the present application is not limited thereto. Rather, various equivalent modifications or replacements can be conceived within the technical scope disclosed in the present application, and these equivalent modifications or replacements are all covered by the scope of protection of the present application.

Claims

1. A voltage screening device, characterized in that: include: a voltage screening module configured to provide a driving voltage based on an input voltage; and The logic control module is configured to control the voltage screening module so that the driving voltage is within a predetermined range.

2. The voltage screening device according to claim 1, characterized in that: The voltage screening module includes: a voltage comparator configured to provide an output voltage based on a comparison of the input voltage and a first reference voltage; a voltage divider configured to provide a divided voltage based on the input voltage; a voltage follower configured to provide a following voltage based on the divided voltage; The first switch tube is configured to be turned off or on according to the control of the logic control module, so that the output voltage or the follower voltage is used as the driving voltage.

3. The voltage screening device according to claim 2, characterized in that: The voltage comparator has a non-inverting input terminal, an inverting input terminal and an output terminal, wherein the non-inverting input terminal is used to receive the first reference voltage, the inverting input terminal is used to receive the input voltage, and the output terminal is used to provide the output voltage.

4. The voltage screening device according to claim 3, characterized in that: The voltage divider includes: a second resistor and a third resistor, the first end of the second resistor is used to receive the input voltage, the second end of the second resistor is connected to the first end of the third resistor, the second end of the third resistor is grounded, and the connection point between the second end of the second resistor and the first end of the third resistor is used to provide a divided voltage.

5. The voltage screening device according to claim 4, characterized in that: The voltage follower has a non-inverting input terminal, an inverting input terminal and an output terminal, the non-inverting input terminal is connected to the connection point of the second end of the second resistor and the first end of the third resistor in the voltage divider to receive the divided voltage, the inverting input terminal is connected to the output terminal, and the output terminal is connected to the first switching tube.

6. The voltage screening device according to claim 5, characterized in that: The first switching tube has an emitter, a collector and a base. The emitter is connected to the output end of the voltage follower and is connected to the logic control module via a fourth resistor. The collector is connected to the output end of the voltage comparator via a fifth resistor and is grounded via a first capacitor and serves as the output end of the voltage screening device. The base is connected to the logic control module.

7. The voltage screening device according to any one of claims 2 to 6, characterized in that: The logic control module is configured to control the first switch tube to be turned on or off based on the output voltage.

8. The voltage screening device according to claim 7, characterized in that: The logic control module is configured to: When the output voltage is at a high level, controlling the first switch tube to be turned off; When the output voltage is at a low level, the first switch tube is controlled to be turned on.

9. The voltage screening device according to claim 8, characterized in that: The logic control module includes: a second switching tube, wherein a base of the second switching tube is connected to the output end of the voltage comparator of the voltage screening module via a sixth resistor and is grounded via a seventh resistor, an emitter of the second switching tube is grounded, and a collector of the second switching tube receives a second reference voltage via an eighth resistor; and a third switching tube, the base of the third switching tube is connected to the collector of the second switching tube via a ninth resistor and is grounded via a tenth resistor, the emitter of the third switching tube is grounded, and the collector of the third switching tube is connected to the base of the first switch of the voltage screening module via an eleventh resistor.

10. The voltage screening device according to claim 8, characterized in that: The logic control module includes: An eleventh resistor, wherein a first end of the eleventh resistor is connected to the base of the first switch tube of the voltage screening module, and a second end of the eleventh resistor is connected to the output end of the voltage comparator of the voltage screening module.

11. A device based on a power switch tube, characterized in that it comprises: Power switch tube; The voltage screening device according to any one of claims 1 to 10, configured to provide a driving voltage for the power switch tube.

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