Driving circuit of power module
By introducing the emitter follow-on module into the power module driving circuit, providing additional driving current, the problem that the driving chip in the prior art cannot meet the high load current requirements is solved, the loss and cost are reduced, and the driving capability and shutdown are optimized. Strategy.
Patent Information
- Application Number
- CN202420287343.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-07
- Publication Date
- 2024-12-27
- Estimated Expiration
- 2034-02-07
AI Technical Summary
When the IGBT output load current is large, the existing power module driving circuit cannot provide sufficient gate driving current, resulting in high switching losses. The multiple push-pull driving circuits are costly and occupy a large area, so they cannot fully utilize them. The driving capability of the driver chip and the risk of hard shutdown.
A power module driving circuit is designed. By electrically connecting the emitter follow-on module at the output end of the drive chip, the emitter follow-on module provides additional driving current in the on-state, which increases the overall driving current and drives the chip. Soft shutdown is achieved with small output current, reducing the risk of waste and hard shutdown.
Improves the driving current output of the power module, reduces switching losses, reduces circuit cost and area occupied, fully utilizes the driving capability of the driver chip, reduces the risk of hard shutdown after desaturation, and optimizes the opening in small current situations. speed.
Smart Images
Figure CN222262477U_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the field of circuit technology, and in particular, relates to a driving circuit of a power module. Background Art
[0002] With the development of science and technology, the application of power modules such as insulated gate bipolar transistors (IGBT) is becoming more and more widespread. When the load current output by the IGBT is large, the IGBT requires a higher gate drive current so that the gate voltage can be established as quickly as possible to achieve rapid turn-on and turn-off of the IGBT and reduce switching losses. Utility Model Content
[0003] An embodiment of the present application provides a driving circuit of a power module, which can increase the driving current output by the driving circuit of the power module and reduce the switching loss of the power module.
[0004] In the first aspect, an embodiment of the present application provides a driving circuit of a power module, including: a driving chip, the output end of the driving chip is electrically connected to the input end of the power module, and the output end of the driving chip is used to provide a first driving current to the input end of the power module; an emitter follower turn-on module, the control end of the emitter follower turn-on module is electrically connected to the output end of the driving chip, the first end of the emitter follower turn-on module is electrically connected to the first power supply signal end, the second end of the emitter follower turn-on module is electrically connected to the input end of the power module, and when the emitter follower turn-on module is in the on state, it is used to provide a second driving current to the input end of the power module.
[0005] According to the implementation scheme of the first aspect of the present application, the emitter follower turn-on module includes: a first amplifier unit, the control end of the first amplifier unit is electrically connected to the output end of the driver chip, the first end of the first amplifier unit is electrically connected to the first power signal end, and the second end of the first amplifier unit is electrically connected to the input end of the power module; a first gate drive resistor unit, the first end of the first gate drive resistor unit is electrically connected to the output end of the driver chip and the control end of the first amplifier unit, respectively, and the second end of the first gate drive resistor unit is electrically connected to the second end of the first amplifier unit and the input end of the power module, respectively; a second gate drive resistor unit, the second gate drive resistor unit is electrically connected between the second end of the first amplifier unit and the input end of the power module.
[0006] According to any of the aforementioned embodiments of the first aspect of the present application, the emitter follower activation module also includes: a first emitter output trigger unit, the first end of the first emitter output trigger unit is electrically connected to the output end of the driving chip, and the second end of the first emitter output trigger unit is electrically connected to the control end of the first amplification unit; a first capacitor, the first capacitor is connected in parallel with the first emitter output trigger unit.
[0007] According to any of the aforementioned embodiments of the first aspect of the present application, the driving circuit also includes: an emitter follower shutdown module, a control end of the emitter follower shutdown module is electrically connected to the input end of the driving chip, a first end of the emitter follower shutdown module is electrically connected to the input end of the power module, and a second end of the emitter follower shutdown module is electrically connected to the second power supply signal end.
[0008] According to any of the aforementioned embodiments of the first aspect of the present application, the emitter follower shutdown module includes: a second amplifier unit, the control end of the second amplifier unit is electrically connected to the input end of the driver chip, the first end of the second amplifier unit is electrically connected to the input end of the power module, and the second end of the second amplifier unit is electrically connected to the second power supply signal end; a third gate drive resistor unit, the first end of the third gate drive resistor unit is electrically connected to the first end of the second amplifier unit and the input end of the power module, respectively, and the second end of the third gate drive resistor unit is electrically connected to the control end of the second amplifier unit and the input end of the driver chip, respectively; a fourth gate drive resistor unit, the fourth gate drive resistor unit is electrically connected between the first end of the second amplifier unit and the input end of the power module.
[0009] According to any of the aforementioned embodiments of the first aspect of the present application, the emitter follower shutdown module also includes: a second emitter output trigger unit, a first end of the second emitter output trigger unit is electrically connected to the input end of the driving chip, and a second end of the second emitter output trigger unit is electrically connected to the control end of the second amplification unit; a second capacitor, and the second capacitor is connected in parallel with the second emitter output trigger unit.
[0010] According to any of the aforementioned embodiments of the first aspect of the present application, the driving circuit also includes: a third capacitor, a first plate of the third capacitor is electrically connected to the control end of the first amplifying unit, and a second plate of the third capacitor is electrically connected to the second end of the first amplifying unit; a fourth capacitor, a first plate of the fourth capacitor is electrically connected to the control end of the second amplifying unit, and a second plate of the fourth capacitor is electrically connected to the first end of the second amplifying unit.
[0011] According to any of the aforementioned implementations of the first aspect of the present application, the control end of the emitter follower shutdown module is electrically connected to the control end of the emitter follower turn-on module.
[0012] According to any of the aforementioned embodiments of the first aspect of the present application, the first amplification unit includes a first N-type transistor, and the second amplification unit includes a first P-type transistor; the base of the first N-type transistor is electrically connected to the output end of the driving chip, the collector of the first N-type transistor is electrically connected to the first power supply signal end, and the emitter of the first N-type transistor is electrically connected to the input end of the power module; the base of the first P-type transistor is electrically connected to the input end of the driving chip, the emitter of the first P-type transistor is electrically connected to the input end of the power module, and the collector of the first P-type transistor is electrically connected to the second power supply signal end.
[0013] According to any of the aforementioned embodiments of the first aspect of the present application, the first amplification unit includes a first N-type transistor, and the second amplification unit includes a first P-type transistor; the gate of the first N-type transistor is electrically connected to the output end of the driving chip, the first pole of the first N-type transistor is electrically connected to the first power supply signal end, and the second pole of the first N-type transistor is electrically connected to the input end of the power module; the gate of the first P-type transistor is electrically connected to the input end of the driving chip, the first pole of the first P-type transistor is electrically connected to the input end of the power module, and the second pole of the first P-type transistor is electrically connected to the second power supply signal end.
[0014] The driving circuit of the power module of the embodiment of the present application includes a driving chip and an emitter follower opening module, the output end of the driving chip is electrically connected to the input end of the power module, and the output end of the driving chip is used to provide a first driving current to the input end of the power module; the control end of the emitter follower opening module is electrically connected to the output end of the driving chip, the first end of the emitter follower opening module is electrically connected to the first power signal end, and the second end of the emitter follower opening module is electrically connected to the input end of the power module. When the emitter follower opening module is in a conducting state, it is used to provide a second driving current to the input end of the power module. On the one hand, the driving current output by the driving circuit of the power module can be the sum of the first driving current and the second driving current, so the driving current output by the driving circuit of the power module can be increased, that is, a larger driving current is provided to the power module, and the switching loss of the power module is reduced. On the other hand, the driving capability of the driving chip itself can be fully utilized, that is, the first driving current output by the driving chip itself can be provided to the power module, reducing the waste of the first driving current output by the driving chip. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In order to more clearly illustrate the technical solution of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.
[0016] Figure 1 A circuit diagram of a driving circuit of a power module in the related art;
[0017] Figure 2 A circuit diagram of a driving circuit of a power module provided in an embodiment of the present application;
[0018] Figure 3 Another circuit diagram of a driving circuit of a power module provided in an embodiment of the present application;
[0019] Figure 4 A further circuit diagram of a driving circuit of a power module provided in an embodiment of the present application;
[0020] Figure 5 A further circuit diagram of a driving circuit of a power module provided in an embodiment of the present application;
[0021] Figure 6 A further circuit diagram of a driving circuit of a power module provided in an embodiment of the present application;
[0022] Figure 7 A further circuit diagram of a driving circuit of a power module provided in an embodiment of the present application;
[0023] Figure 8 A further circuit diagram of a driving circuit of a power module provided in an embodiment of the present application;
[0024] Fig. 9 Another circuit diagram of a driving circuit of a power module provided in an embodiment of the present application. DETAILED DESCRIPTION
[0025] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be 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 intended to explain the present application, rather than to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating the examples of the present application.
[0026] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.
[0027] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.
[0028] In the embodiments of the present application, the term “electrically connected” may refer to a direct electrical connection between two components, or may refer to an electrical connection between two components via one or more other components.
[0029] It is obvious to those skilled in the art that various modifications and changes can be made in the present application without departing from the spirit or scope of the present application. Therefore, the present application is intended to cover modifications and changes of the present application that fall within the scope of the corresponding claims (technical solutions for protection) and their equivalents. It should be noted that the implementation methods provided in the embodiments of the present application can be combined with each other without contradiction.
[0030] Before describing the technical solutions provided by the embodiments of the present application, in order to facilitate the understanding of the embodiments of the present application, the present application first specifically describes the problems existing in the related art:
[0031] When the load current output by the IGBT is large, the IGBT requires a higher gate drive current so that the gate voltage can be established as quickly as possible to achieve rapid turn-on and turn-off of the IGBT and reduce switching losses.
[0032] Exemplarily, the expression of the gate drive current of the IGBT is as follows:
[0033] Igate=(Vcc-Vee) / (Rgint+Rg) (1)
[0034] Among them, Igate represents the peak gate drive current of the IGBT; Vcc represents the gate drive positive power supply voltage. For example, for IGBT, Vcc includes but is not limited to +15V; Vee represents the gate drive negative power supply voltage. For example, for IGBT, Vee includes but is not limited to -8V; Rgint represents the gate resistance integrated inside the IGBT; Rg is the necessary gate drive resistance.
[0035] For example, taking Vcc = +15V, Vee = -8V, Rgint = 0.95Ω, Rg = 1Ω, the above expression (1) is calculated to obtain
[0036] Igate≈11.7A
[0037] When the load current required by the IGBT output is large, such as when the IGBT drives mining equipment, two IGBTs can be connected in parallel.
[0038] 2*Igate≈23.5A
[0039] However, the driving current requirement has far exceeded the current capabilities of current driver chips. For example, the upper limit of the driver chip's driving on-current is 11A, and the upper limit of the off-current is 12A, which is far from meeting the needs of application scenarios where the IGBT output has a large load current.
[0040] In order to adapt to the application scenario where the load current output by the IGBT is large, multiple push-pull drive circuits can be connected in parallel outside the driver chip to increase the drive current provided to the IGBT.
[0041] Figure 1 FIG. 1 is a circuit diagram of a driving circuit of a power module in the related art. Figure 1 As shown, in the related art, the driving circuit of the power module may include a driving chip 101 ′ and a plurality of push-pull driving circuits 102 ′ connected in parallel. Figure 1 Take two groups of push-pull drive circuits 102' as an example, for example, the two groups of push-pull drive circuits 102' include a push-pull drive circuit 1021' and a push-pull drive circuit 1022'. The push-pull drive circuit 1021' may include a first transistor Q1' and a second transistor Q2', and the push-pull drive circuit 1022' may include a third transistor Q3' and a fourth transistor Q4'.
[0042] The output terminal GH of the driver chip 101' can output a driving current. The push-pull driving circuit 1021' can be electrically connected to the output terminal GH of the driver chip 101', and the push-pull driving circuit 1021' can amplify the driving current of the driver chip 101', and transmit the amplified driving current to the power module 30'. Similarly, the push-pull driving circuit 1022' can also be electrically connected to the output terminal GH of the driver chip 101', and the push-pull driving circuit 1022' can amplify the driving current of the driver chip 101', and transmit the amplified driving current to the power module 30'. Therefore, the driving current received by the power module 30' can be the sum of the amplified driving current output by the push-pull driving circuit 1021' and the amplified driving current output by the push-pull driving circuit 1022', thereby providing a larger driving current to the power module 30', so as to be suitable for application scenarios where the load current output by the power module 30' is larger.
[0043] Depend on Figure 1It can be seen that in the related art, the output terminal GH of the driver chip 101' is not directly electrically connected to the input terminal of the power module 30', and a push-pull driving circuit 1021' is also provided between the output terminal GH of the driver chip 101' and the input terminal of the power module 30'. In other words, the driving current output by the driver chip 101' does not directly participate in the gate driving of the power module 30', but is used to control the conduction of the transistor in the push-pull driving circuit 102', and indirectly realizes the gate driving of the power module 30' through the push-pull driving circuit 1021'. In this case, the following problems may arise:
[0044] 1) The cost of multiple push-pull drive circuits is high, such as Figure 1 As shown, usually Q1', Q2', Q3' and Q4' are all relatively high-power bipolar junction transistors (BJTs), which have high withstand voltage requirements. The cost of BJTs is high, and the cost of multiple push-pull combinations even exceeds the cost of the driver chip itself.
[0045] 2) Multiple push-pull drive circuits will occupy a large area of the circuit board. The device packages of Q1', Q2', Q3' and Q4' are usually SOT-89 packages or discrete packages (i.e. DPAK packages), which usually occupy a large area of the circuit board;
[0046] 3) When using a push-pull drive circuit, the drive capability of the driver chip itself cannot be fully utilized, resulting in a waste of cost;
[0047] 4) Usually the driver chip has a desaturation protection mechanism. When desaturation occurs, the driver chip will provide a lower driving current to the power module, and the power module will achieve soft shutdown through a lower driving current to prevent the power module from being shut down due to hard shutdown under high current conditions, resulting in a shutdown overvoltage exceeding the device's tolerance range. However, when the push-pull drive circuit is added for amplification, the push-pull drive circuit will amplify the output current of the driver chip, causing the drive current received by the power module to be always large, making it impossible to achieve soft shutdown of the power module, and the power module is at risk of hard shutdown after desaturation.
[0048] In view of the above research findings of the inventors, an embodiment of the present application provides a driving circuit of a power module, which can solve at least one of the above technical problems existing in the related art.
[0049] Figure 2 A circuit diagram of a driving circuit of a power module provided in an embodiment of the present application. Figure 2As shown, the driving circuit 20 of the power module may include a driving chip 201 and an emitter follower turn-on module 202. The driving chip 201 includes but is not limited to a single-channel isolated gate driver or a multi-channel isolated gate driver. The output terminal GH of the driving chip 201 may be electrically connected to the input terminal of the power module 30, and the output terminal GH of the driving chip 201 may be used to provide a first driving current I1 to the input terminal of the power module 30. The power module 30 includes but is not limited to power semiconductor devices such as IGBT.
[0050] The control end of the emitter follower opening module 202 can be electrically connected to the output end GH of the driver chip 201, the first end of the emitter follower opening module 202 can be electrically connected to the first power signal end VCC, and the second end of the emitter follower opening module 202 can be electrically connected to the input end of the power module 30. Among them, the first power signal end VCC can be used to output a positive voltage signal, that is, an electrical signal with a voltage value greater than 0V. The emitter follower opening module 202 can be turned on or off in response to the first drive current I1 of the output end GH of the driver chip 201. For example, when the first drive current I1 of the output end GH of the driver chip 201 is large, the emitter follower opening module 202 can be turned on. When the first drive current I1 of the output end GH of the driver chip 201 is small, the emitter follower opening module 202 can be turned off. When the emitter follower opening module 202 is in the on state, the emitter follower opening module 202 can be used to provide a second drive current I2 to the input end of the power module 30. Specifically, when the emitter follower turn-on module 202 is in the on state, the current of the first power signal terminal VCC can flow to the input terminal of the power module 30 through the emitter follower turn-on module 202 .
[0051] In this way, on the one hand, the driving current output by the driving circuit 20 of the power module can be the sum of the first driving current and the second driving current, so the driving current output by the driving circuit 20 of the power module can be increased, that is, a larger driving current is provided to the power module, and the switching loss of the power module is reduced. On the other hand, the driving capability of the driver chip itself can be fully utilized, that is, the first driving current output by the driver chip itself can be provided to the power module, reducing the waste of the first driving current output by the driver chip. On the other hand, when the first driving current at the output end of the driver chip is small, the emitter follower opening module responds to the first driving current at the output end of the driver chip and shuts down, and no longer provides the second driving current to the input end of the power module. Only the driver chip provides a smaller first driving current to the input end of the power module. In this way, the power module can achieve soft shutdown based on the smaller first driving current, reducing the risk of hard shutdown after the power module is desaturated.
[0052] On the other hand, by matching the first driving current at the output end of the driver chip and the second driving current of the emitter follower turn-on module 202, when the load current of the power module is small (the gate driving current of the power module is also small at this time), only the first driving current of the lower driver chip drives the power module, thereby optimizing the ringing phenomenon of the diode of the power module caused by too fast turn-on speed under low current conditions.
[0053] Figure 3 Another circuit diagram of the driving circuit of the power module provided in the embodiment of the present application. Figure 3 As shown, according to some embodiments of the present application, optionally, the emitter follower turn-on module 202 may include a first amplifying unit 301, a first gate driving resistor unit 302, and a second gate driving resistor unit 303. The control end of the first amplifying unit 301 is electrically connected to the output end GH of the driver chip 201, the first end of the first amplifying unit 301 is electrically connected to the first power signal end VCC, and the second end of the first amplifying unit 301 is electrically connected to the input end of the power module 30.
[0054] The first end of the first gate drive resistor unit 302 is electrically connected to the output end GH of the driver chip 201 and the control end of the first amplifier unit 301 , and the second end of the first gate drive resistor unit 302 is electrically connected to the second end of the first amplifier unit 301 and the input end of the power module 30 .
[0055] The first gate drive resistor unit 302 can be used to limit the magnitude of the first drive current I1, and implement overcurrent protection for the power module 30. In addition, when the first drive current I1 flows through the first gate drive resistor unit 302, a voltage drop will be generated in the first gate drive resistor unit 302. When the voltage drop of the first gate drive resistor unit 302 is greater than the turn-on voltage Vbe of the first amplifier unit 301, the first amplifier unit 301 is turned on, and the current of the first power signal terminal VCC can flow to the input terminal of the power module 30 through the first amplifier unit 301, that is, the first amplifier unit 301 provides the second drive current I2 to the input terminal of the power module 30.
[0056] When the current value of the first drive current I1 is small, the voltage drop of the first gate drive resistor unit 302 is small. When the voltage drop of the first gate drive resistor unit 302 is less than the turn-on voltage Vbe of the first amplifier unit 301, the first amplifier unit 301 is turned off, and the first amplifier unit 301 no longer provides the second drive current I2 to the input end of the power module 30. At this time, only the driver chip 201 provides the smaller first drive current I1 to the input end of the power module 30. In this way, the power module 30 can achieve soft shutdown based on the smaller first drive current I1, reducing the risk of hard shutdown of the power module 30 after desaturation.
[0057] The second gate drive resistor unit 303 is electrically connected between the second end of the first amplifying unit 301 and the input end of the power module 30. The second gate drive resistor unit 303 can be used to adjust the output of the emitter follower turn-on module 202. For example, the second gate drive resistor unit 303 can be used to adjust the output current of the emitter follower turn-on module 202. The second gate drive resistor unit 303 can adjust the driving capability of the emitter follower turn-on module 202 so that the power module 30 can be properly driven.
[0058] In some specific embodiments, the first amplifying unit 301 includes but is not limited to a triode or a metal-oxide-semiconductor field-effect transistor (MOSFET), which will be described in detail below and will not be repeated here. Figure 3 The first amplifying unit 301 is taken as a triode for example. When the first amplifying unit 301 is a triode, the turn-on voltage Vbe of the first amplifying unit 301 includes the voltage difference between the base and the emitter of the triode. When the first amplifying unit 301 is a transistor, the turn-on voltage Vbe of the first amplifying unit 301 includes the voltage difference between the gate and the source of the transistor.
[0059] In some specific embodiments, the first gate drive resistance unit 302 includes but is not limited to a first resistor R1, a first end of the first resistor R1 is electrically connected to the output end GH of the driving chip 201 and the control end of the first amplifying unit 301, and a second end of the first resistor R1 is electrically connected to the second end of the first amplifying unit 301 and the input end of the power module 30.
[0060] Figure 4 This is another circuit diagram of a driving circuit of a power module provided in an embodiment of the present application. Figure 4 As shown, according to some embodiments of the present application, optionally, the emitter follower turn-on module 202 may further include a first emitter output trigger unit 401 and a first capacitor C1.
[0061] The first end of the first emitter output trigger unit 401 is electrically connected to the output end GH of the driver chip 201, and the second end of the first emitter output trigger unit 401 is electrically connected to the control end of the first amplifier unit 301. The first emitter output trigger unit 401 can be used to limit the current of the control end of the first amplifier unit 301 to prevent the first amplifier unit 301 from being damaged when the first drive current I1 is too large.
[0062] The first capacitor C1 may be connected in parallel with the first emitter output trigger unit 401. That is, the first plate of the first capacitor C1 may be electrically connected to the first end of the first emitter output trigger unit 401, and the second plate of the first capacitor C1 may be electrically connected to the second end of the first emitter output trigger unit 401.
[0063] The first capacitor C1 can be used to adjust the delay time between the second drive current I2 output by the first amplifying unit 301 and the first drive current I1 output by the driver chip, so that the delay between the second drive current I2 output by the first amplifying unit 301 and the first drive current I1 output by the driver chip is reduced to an acceptable range.
[0064] Specifically, when the first capacitor C1 just starts to charge, the first capacitor C1 is short-circuited, and the branch where the first capacitor C1 is located is equivalent to a wire. Therefore, the first drive current I1 output by the driver chip will quickly reach the control end of the first amplifier unit 301 through the branch where the first capacitor C1 is located, which is conducive to quickly turning on the first amplifier unit 301, thereby reducing the delay time between the second drive current I2 output by the first amplifier unit 301 and the first drive current I1 output by the driver chip.
[0065] Since the first capacitor C1 has the performance of blocking DC and passing AC, as the first capacitor C1 is charged, when the voltage of the first capacitor C1 reaches a certain threshold, the first driving current I1 output by the driver chip can no longer reach the control end of the first amplifying unit 301 through the branch where the first capacitor C1 is located. The branch where the first capacitor C1 is located is equivalent to a short circuit, and the first driving current I1 reaches the control end of the first amplifying unit 301 through the first emitter output trigger unit 401. The first emitter output trigger unit 401 plays a role of overcurrent protection.
[0066] In some specific embodiments, the first emitter output trigger unit 401 includes but is not limited to a second resistor R2 . A first end of the second resistor R2 is electrically connected to the output terminal GH of the driver chip 201 , and a second end of the second resistor R2 is electrically connected to the control terminal of the first amplifying unit 301 .
[0067] Figure 5 This is another circuit diagram of a driving circuit of a power module provided in an embodiment of the present application. Figure 5 As shown, according to some embodiments of the present application, optionally, the driving circuit 20 may also include an emitter follower shutdown module 501, the control end of the emitter follower shutdown module 501 is electrically connected to the input end GI of the driving chip 201, the first end of the emitter follower shutdown module 501 is electrically connected to the input end of the power module 30, and the second end of the emitter follower shutdown module 501 is electrically connected to the second power supply signal end VEE.
[0068] Among them, the second power supply signal terminal VEE can be used to output a negative voltage signal, that is, an electrical signal with a voltage value less than 0V. The emitter follower shutdown module 501 can be turned on or off in response to the current of the input terminal GI of the driver chip 201. When the emitter follower shutdown module 501 is in the on state, the emitter follower shutdown module 501 can be used to transmit the current at the input terminal of the power module 30 to the input terminal GI and / or the second power supply signal terminal VEE of the driver chip 201. Specifically, when the emitter follower shutdown module 501 is in the on state, the current at the input terminal of the power module 30 can flow to the input terminal GI and / or the second power supply signal terminal VEE of the driver chip 201 through the emitter follower shutdown module 501 to achieve discharge.
[0069] Figure 6 This is another circuit diagram of a driving circuit of a power module provided in an embodiment of the present application. Figure 6 As shown, according to some embodiments of the present application, optionally, the emitter follower turn-off module 501 may include a second amplifying unit 601, a third gate drive resistor unit 602, and a fourth gate drive resistor unit 604. The control end of the second amplifying unit 601 is electrically connected to the input end GI of the driver chip 201, the first end of the second amplifying unit 601 is electrically connected to the input end of the power module 30, and the second end of the second amplifying unit 601 is electrically connected to the second power signal end VEE.
[0070] The first end of the third gate drive resistor unit 602 is electrically connected to the first end of the second amplifier unit 601 and the input end of the power module 30 respectively, and the second end of the third gate drive resistor unit 602 is electrically connected to the control end of the second amplifier unit 601 and the input end GI of the driver chip 201 respectively.
[0071] The third gate drive resistor unit 602 can be used to limit the current size of the input terminal GI of the driver chip 201, so as to realize overcurrent protection for the driver chip 201. In addition, when the current inputted from the input terminal GI of the driver chip 201 flows through the third gate drive resistor unit 602, the third gate drive resistor unit 602 will generate a voltage drop. When the voltage drop of the third gate drive resistor unit 602 is greater than the turn-on voltage Vbe of the second amplifier unit 601, the second amplifier unit 601 is turned on, and the current at the input terminal of the power module 30 can flow to the second power signal terminal VEE through the second amplifier unit 601.
[0072] The fourth gate drive resistor unit 604 is electrically connected between the first end of the second amplifying unit 601 and the input end of the power module 30. The fourth gate drive resistor unit 604 can be used to adjust the output of the emitter follower turn-off module 501. For example, the fourth gate drive resistor unit 604 can be used to adjust the output current of the emitter follower turn-off module 501. The fourth gate drive resistor unit 604 can adjust the driving capability of the emitter follower turn-off module 501 so that the power module 30 can be properly driven.
[0073] In some specific embodiments, the second amplifying unit 601 includes but is not limited to a triode or a MOSFET, which will be described in detail below and will not be repeated here. Figure 6 The second amplifying unit 601 is taken as a triode for example. When the second amplifying unit 601 is a triode, the turn-on voltage Vbe of the second amplifying unit 601 includes the voltage difference between the base and the emitter of the triode. When the second amplifying unit 601 is a transistor, the turn-on voltage Vbe of the second amplifying unit 601 includes the voltage difference between the gate and the source of the transistor.
[0074] In some specific embodiments, the third gate drive resistance unit 602 includes but is not limited to a third resistor R3, a first end of the third resistor R3 is electrically connected to the first end of the second amplifier unit 601 and the input end of the power module 30, and a second end of the third resistor R3 is electrically connected to the control end of the second amplifier unit 601 and the input end GI of the driver chip 201.
[0075] Continue to see Figure 6 According to some embodiments of the present application, optionally, the emitter follower shutdown module also includes a second emitter output trigger unit 603 and a second capacitor C2.
[0076] The first end of the second emitter output trigger unit 603 is electrically connected to the input end GI of the driving chip 201, and the second end of the second emitter output trigger unit 603 is electrically connected to the control end of the second amplifying unit 601. The second emitter output trigger unit 603 can be used to limit the current of the control end of the second amplifying unit 601 to prevent the second amplifying unit 601 from being damaged when the current is too large.
[0077] The second capacitor C2 is connected in parallel with the second emitter output trigger unit 603. That is, the first end of the second capacitor C2 is electrically connected to the first end of the second emitter output trigger unit 603, and the second end of the second capacitor C2 is electrically connected to the second end of the second emitter output trigger unit 603.
[0078] The second capacitor C2 can be used to adjust the delay time between the current output by the second amplifying unit 601 and the discharge current of the power module 30, so that the delay between the current output by the second amplifying unit 601 and the discharge current of the power module 30 is reduced to an acceptable range.
[0079] The working principle of the second capacitor C2 can refer to the description of the working principle of the first capacitor C1, which will not be repeated here.
[0080] In some specific embodiments, the second emitter output trigger unit 603 includes but is not limited to a fourth resistor R4, a first end of the fourth resistor R4 is electrically connected to the input end GI of the driving chip 201, and a second end of the fourth resistor R4 is electrically connected to the control end of the second amplification unit 601.
[0081] In some specific embodiments, the second gate driving resistance unit 303 includes but is not limited to a fifth resistor R5 , and the fourth gate driving resistance unit 604 includes but is not limited to a sixth resistor R6 .
[0082] Figure 7 This is another circuit diagram of a driving circuit of a power module provided in an embodiment of the present application. Figure 7 As shown, according to some embodiments of the present application, optionally, the driving circuit 20 further includes a third capacitor C3 and a fourth capacitor C4. The first plate of the third capacitor C3 is electrically connected to the control end of the first amplifying unit 301, and the second plate of the third capacitor C3 is electrically connected to the second end of the first amplifying unit 301. The first plate of the fourth capacitor C4 is electrically connected to the control end of the second amplifying unit 601, and the second plate of the fourth capacitor C4 is electrically connected to the first end of the second amplifying unit 601.
[0083] The third capacitor C3 can be used to maintain the voltage difference between the potential of the control end of the first amplifier unit 301 and the potential of the second end of the first amplifier unit 301 to be greater than the turn-on voltage Vbe of the first amplifier unit 301, so that the first amplifier unit 301 remains in the on state. In this way, during the driving process of the power module, when the voltage at the input end (such as the gate) of the power module reaches the Miller platform, a large driving current can be maintained for a period of time, thereby optimizing the loss.
[0084] Specifically, the gate drive of the power module can be divided into two stages. The first is the initial charging stage. At this time, the first drive current of the driver chip is relatively large, but a spike will appear after a period of time, and a Miller platform will appear after the spike, because at this time the voltage difference between the output end of the driver chip and the gate of the power module becomes lower, so the first drive current will decrease. In the second charging stage, the parallel emitter follower opening module 202 outputs the second drive current, and the drive current is the sum of the first drive current and the second drive current, and the drive current will become larger. The third capacitor C3 can keep the first amplification unit 301 in the on state, so that during the driving process of the power module, when the voltage at the input end (such as the gate) of the power module reaches the Miller platform, it can maintain a relatively large drive current for a period of time, thereby optimizing the loss.
[0085] Similarly, the fourth capacitor C4 can be used to keep the voltage difference between the potential of the first end of the second amplifier unit 601 and the potential of the control end of the second amplifier unit 601 greater than the start-up voltage Vbe of the second amplifier unit 601, so that the second amplifier unit 601 remains in the on state.
[0086] Figure 8 This is another circuit diagram of a driving circuit of a power module provided in an embodiment of the present application. Figure 8 As shown, according to some embodiments of the present application, optionally, the control end of the emitter follower turn-off module 501 can be electrically connected to the control end of the emitter follower turn-on module 202. That is, the input end GI of the driver chip 201 can be electrically connected to the output end GH of the driver chip 201.
[0087] for Figure 8 In the driving circuit of the power module shown, the driving current output by the emitter follower opening module 202 is related to the first driving current output by the driving chip, and is also related to the amplification capability of the first amplification unit 301. The expression of the driving current output by the emitter follower opening module 202 is as follows:
[0088] I_C_Q1= min[(I_gh* R1 / / R3–I_be_Q1*R2-Vbe_Q1) / R5,β* I_be_Q1] (2)
[0089] Among them, I_C_Q1 represents the driving current output by the emitter follower opening module 202 (i.e., the first amplifying unit 301); I_gh represents the first driving current output by the driving chip, which is affected by the output capability of the driving chip itself and the external series impedance, and I_gh is known; I_be_Q1 represents the current value that makes the first amplifying unit 301 reach saturation conduction, which is usually 10mA to 100mA, for example, an average of 50mA can be taken; Vbe_Q1 represents the opening voltage of the first amplifying unit 301, which is usually 0.7V; β represents the DC amplification factor of the first amplifying unit 301, which is known. R1 represents the resistance value of the first resistor R1, R2 represents the resistance value of the second resistor R2, R3 represents the resistance value of the third resistor R3, and R5 represents the resistance value of the fifth resistor R5.
[0090] For example, in some specific examples, assuming that the current value of the first driving current output by the driving chip is 5A, the above expression (2) can be:
[0091] I_C_Q1=min[(5A*0.5Ω-50mA*10Ω-0.7V) / 1ohm,200*50mA]=1.3A
[0092] Then the total gate drive current of the power module is 5+1.3=6.3A.
[0093] When the current value of the first driving current output by the driving chip is 10A, the total driving current of the gate of the power module can be obtained as 13.8A through the above expression (2).
[0094] It should be noted that the calculated total gate drive current of the power module is the upper limit of theoretical calculation, and the actual value needs to refer to the characteristics of the first amplification unit 301 itself and the influence of temperature.
[0095] When the power module is turned off, the calculation formula of its turn-off current is the same as the calculation formula of the turn-on current, which will not be repeated here. Only the soft turn-off example is given below.
[0096] When the driver chip is in the soft-off state, assuming that the current value of the first drive current output by the driver chip is 1A, the above expression (2) can be obtained:
[0097] I_C_Q1=-0.7A.
[0098] The drive current output by the emitter follower opening module 202 is negative, which means that the emitter follower opening module 202 cannot be turned on. The emitter follower opening module 202 does not work and will not affect the soft shutdown strategy of the driver chip itself.
[0099] It should be noted that the above parameters are taken for ease of understanding, and should be adjusted as needed in actual applications. For example, when R1 and R3 are changed to 2Ω, and the current value of the first drive current output by the driver chip is 10A, the total drive current of the gate of the power module will reach 18.8A.
[0100] Continue to see Figure 7 According to other embodiments of the present application, optionally, the control end of the emitter follower turn-off module 501 may not be electrically connected to the control end of the emitter follower turn-on module 202. That is, the input end GI of the driver chip 201 is not electrically connected to the output end GH of the driver chip 201.
[0101] At this time, the expression of the driving current output by the emitter follower opening module 202 is as follows:
[0102] I_C_Q1= min[(I_gh* R1–I_be_Q1*R2-Vbe_Q1) / R5,β* I_be_Q1] (3)
[0103] Accordingly, the expression of the driving current input by the emitter follower shutdown module 501 is as follows:
[0104] I_C_Q2= min[(I_gh*R3–I_be_Q2*R4-Vbe_Q2) / R6,β* I_be_Q2] (4).
[0105] Among them, I_C_Q2 represents the drive current output by the emitter follower shutdown module 501 (i.e., the second amplifier unit 601); I_gh represents the first drive current output by the driver chip, which is affected by the output capability of the driver chip itself and the external series impedance, and I_gh is known; I_be_Q2 represents the current value that makes the second amplifier unit 601 reach saturation conduction, which is usually 10mA to 100mA, for example, an average of 50mA can be taken; Vbe_Q2 represents the turn-on voltage of the second amplifier unit 601, which is usually 0.7V; β represents the DC amplification factor of the second amplifier unit 601, which is known. R3 represents the resistance value of the third resistor R3, R4 represents the resistance value of the fourth resistor R4, and R6 represents the resistance value of the sixth resistor R6.
[0106] The calculation process of the above expression (3) is similar to the calculation process of the above expression (2). Figure 7 The embodiments shown and Figure 8 Both of the illustrated embodiments can achieve the same or similar effects.
[0107] like Figure 7 or Figure 8As shown, according to some embodiments of the present application, optionally, the first amplifying unit 301 may include a first N-type transistor Q1, and the second amplifying unit 601 may include a first P-type transistor Q2.
[0108] The base of the first N-type transistor Q1 is electrically connected to the output terminal GH of the driving chip 201 , the collector of the first N-type transistor Q1 is electrically connected to the first power signal terminal VCC, and the emitter of the first N-type transistor Q1 is electrically connected to the input terminal of the power module 30 .
[0109] The base of the first P-type transistor Q2 is electrically connected to the input terminal GI of the driving chip 201 , the emitter of the first P-type transistor Q2 is electrically connected to the input terminal of the power module 30 , and the collector of the first P-type transistor Q2 is electrically connected to the second power signal terminal VEE.
[0110] In this way, on the one hand, the driving circuit of the power module provided in the embodiment of the present application reduces the number of transistors used, thereby reducing the circuit cost; on the other hand, by reducing the number of transistors used, the area of the circuit board occupied by the transistors can be reduced.
[0111] Fig. 9 This is another circuit diagram of a driving circuit of a power module provided in an embodiment of the present application. Fig. 9 As shown, according to some embodiments of the present application, optionally, the first amplifying unit 301 may include a first N-type transistor M1, and the second amplifying unit 601 may include a first P-type transistor M2.
[0112] The gate of the first N-type transistor M1 is electrically connected to the output terminal GH of the driving chip 201 , the first electrode of the first N-type transistor M1 is electrically connected to the first power signal terminal VCC, and the second electrode of the first N-type transistor M1 is electrically connected to the input terminal of the power module 30 .
[0113] The gate of the first P-type transistor M2 is electrically connected to the input terminal GI of the driving chip 201 , the first electrode of the first P-type transistor M2 is electrically connected to the input terminal of the power module 30 , and the second electrode of the first P-type transistor M2 is electrically connected to the second power signal terminal VEE.
[0114] In this way, on the one hand, the driving circuit of the power module provided in the embodiment of the present application reduces the number of transistors used, thereby reducing the circuit cost; on the other hand, by reducing the number of transistors used, the area of the circuit board occupied by the transistors can be reduced.
[0115] It should be understood that the specific structures of the circuits provided in the drawings of the embodiments of the present application are merely examples and are not intended to limit the present application. In addition, the above embodiments provided in the present application may be combined with each other if there is no contradiction.
[0116] It should be clear that each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. According to the embodiments described above in this application, these embodiments do not describe all the details in detail, nor do they limit the application to only the specific embodiments described. Obviously, many modifications and changes can be made based on the above description. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the application, so that technicians in the relevant technical field can make good use of the application and the modified use based on the application. The application is only limited by the claims and their full scope and equivalents.
[0117] Those skilled in the art should understand that the above embodiments are exemplary rather than restrictive. Different technical features appearing in different embodiments can be combined to achieve beneficial effects. Based on the study of the drawings, the specification and the claims, those skilled in the art should be able to understand and implement other variations of the disclosed embodiments. In the claims, the term "comprising" does not exclude other structures; the quantity involves "one" but does not exclude multiple; the terms "first" and "second" are used to indicate names rather than to indicate any specific order. Any figure marks in the claims should not be understood as limiting the scope of protection. The appearance of certain technical features in different dependent claims does not mean that these technical features cannot be combined to achieve beneficial effects.
Claims
1. A driving circuit of a power module, characterized in that: include: A driving chip, wherein an output end of the driving chip is electrically connected to an input end of the power module, and the output end of the driving chip is used to provide a first driving current to the input end of the power module; An emitter follower turn-on module, wherein the control end of the emitter follower turn-on module is electrically connected to the output end of the driving chip, the first end of the emitter follower turn-on module is electrically connected to the first power supply signal end, the second end of the emitter follower turn-on module is electrically connected to the input end of the power module, and when the emitter follower turn-on module is in the on state, it is used to provide a second driving current to the input end of the power module.
2. The driving circuit according to claim 1, characterized in that: The emitter follower opening module comprises: a first amplifying unit, wherein a control end of the first amplifying unit is electrically connected to an output end of the driving chip, a first end of the first amplifying unit is electrically connected to the first power signal end, and a second end of the first amplifying unit is electrically connected to an input end of the power module; a first gate drive resistor unit, wherein a first end of the first gate drive resistor unit is electrically connected to an output end of the driver chip and a control end of the first amplifier unit, and a second end of the first gate drive resistor unit is electrically connected to a second end of the first amplifier unit and an input end of the power module; A second gate driving resistor unit is electrically connected between the second end of the first amplifying unit and the input end of the power module.
3. The driving circuit according to claim 2, characterized in that: The emitter follower opening module also includes: a first emitter output trigger unit, wherein a first end of the first emitter output trigger unit is electrically connected to an output end of the driving chip, and a second end of the first emitter output trigger unit is electrically connected to a control end of the first amplifying unit; A first capacitor is connected in parallel with the first emitter output trigger unit.
4. The driving circuit according to claim 2, characterized in that: The driving circuit further includes: An emitter follower shutdown module, wherein the control end of the emitter follower shutdown module is electrically connected to the input end of the driving chip, the first end of the emitter follower shutdown module is electrically connected to the input end of the power module, and the second end of the emitter follower shutdown module is electrically connected to the second power signal end.
5. The driving circuit according to claim 4, characterized in that: The emitter follower shutdown module comprises: a second amplifying unit, wherein a control end of the second amplifying unit is electrically connected to an input end of the driving chip, a first end of the second amplifying unit is electrically connected to an input end of the power module, and a second end of the second amplifying unit is electrically connected to the second power signal end; a third gate drive resistor unit, wherein a first end of the third gate drive resistor unit is electrically connected to a first end of the second amplifier unit and an input end of the power module, and a second end of the third gate drive resistor unit is electrically connected to a control end of the second amplifier unit and an input end of the driver chip; A fourth gate drive resistor unit is electrically connected between the first end of the second amplifying unit and the input end of the power module.
6. The driving circuit according to claim 5, characterized in that: The emitter follower shutdown module also includes: a second emitter output trigger unit, wherein a first end of the second emitter output trigger unit is electrically connected to an input end of the driving chip, and a second end of the second emitter output trigger unit is electrically connected to a control end of the second amplifying unit; A second capacitor is connected in parallel with the second emitter output trigger unit.
7. The driving circuit according to claim 5, characterized in that: The driving circuit further includes: a third capacitor, wherein a first plate of the third capacitor is electrically connected to the control end of the first amplifying unit, and a second plate of the third capacitor is electrically connected to the second end of the first amplifying unit; A fourth capacitor, wherein a first electrode plate of the fourth capacitor is electrically connected to the control end of the second amplifying unit, and a second electrode plate of the fourth capacitor is electrically connected to the first end of the second amplifying unit.
8. The driving circuit according to claim 5, characterized in that: The control end of the emitter follower turn-off module is electrically connected to the control end of the emitter follower turn-on module.
9. The driving circuit according to claim 5, characterized in that: The first amplifying unit includes a first N-type transistor, and the second amplifying unit includes a first P-type transistor; The base of the first N-type transistor is electrically connected to the output terminal of the driving chip, the collector of the first N-type transistor is electrically connected to the first power signal terminal, and the emitter of the first N-type transistor is electrically connected to the input terminal of the power module; The base of the first P-type transistor is electrically connected to the input end of the driving chip, the emitter of the first P-type transistor is electrically connected to the input end of the power module, and the collector of the first P-type transistor is electrically connected to the second power signal end.
10. The driving circuit according to claim 5, characterized in that: The first amplifying unit includes a first N-type transistor, and the second amplifying unit includes a first P-type transistor; The gate of the first N-type transistor is electrically connected to the output terminal of the driving chip, the first electrode of the first N-type transistor is electrically connected to the first power signal terminal, and the second electrode of the first N-type transistor is electrically connected to the input terminal of the power module; The gate of the first P-type transistor is electrically connected to the input end of the driving chip, the first electrode of the first P-type transistor is electrically connected to the input end of the power module, and the second electrode of the first P-type transistor is electrically connected to the second power signal end.