Switching transistor drive circuit and power conversion device

Abstract

The utility model discloses a kind of switch tube driving circuit and power conversion equipment, belong to driving circuit technical field.Switch tube driving circuit includes: charge-discharge module, the first connecting end of charge-discharge module is connected the drive output end of drive chip, the second connecting end of charge-discharge module is connected the control electrode of switch tube;Charge-discharge module provides the charging path of charging to control electrode when first potential is output in drive output end, and first discharge path of discharging from control electrode to drive chip is provided when second potential is output in drive output end;Discharge control module, the control end of discharge control module is connected first connecting end, the input end of discharge control module is connected control electrode, the output end of discharge control module is connected the main power ground of main power circuit where switch tube is located;Discharge control module is conducted when second potential is output in drive output end, and the second discharge path of discharging from control electrode to main power ground is provided.The utility model embodiment can improve the reliability of switch tube driving control.

Description

Technical Field

[0001] This utility model relates to the field of drive circuits, and in particular to a switch transistor drive circuit and a power conversion device. Background Technology

[0002] In low-voltage, high-current applications, multiple transistors are often connected in parallel, using a single driver chip to drive multiple parallel switching transistors. However, connecting multiple transistors in parallel and using the same driver circuit results in a long drive trace loop connecting to the driver chip. Taking NMOS transistors as an example, when the switching transistor is turned off, due to the long discharge loop of the switching transistor and the large current of the main power circuit, a voltage spike will be generated on the drive signal of the switching transistor after the drive is turned off. The peak value of the voltage spike may exceed the turn-on threshold of the switching transistor, which will cause the switching transistor to operate in the amplification region or be falsely turned on, posing a risk to the entire system. Specifically, if the switching transistor is turned on again in the amplification region or falsely turned on after the drive signal has been set to the cutoff voltage of the switching transistor, it will increase the turn-off loss of the switching transistor and also cause the switching transistor temperature to rise; for the upper and lower transistors in a full-bridge or half-bridge circuit, there is also a risk of the upper and lower transistors exploding due to common communication. Utility Model Content

[0003] This invention provides a switching transistor drive circuit and a power conversion device to improve the reliability of switching transistor drive control.

[0004] In a first aspect, embodiments of the present invention provide a switching transistor driving circuit, comprising:

[0005] A charging and discharging module is provided, wherein a first connection terminal of the charging and discharging module is connected to the drive output terminal of the driver chip, and a second connection terminal of the charging and discharging module is connected to the control electrode of the switching transistor; the charging and discharging module is used to provide a charging path for charging the control electrode of the switching transistor when the drive output terminal outputs a first potential, and to provide a first discharging path for discharging from the control electrode of the switching transistor to the driver chip when the drive output terminal outputs a second potential; the first potential and the second potential are different.

[0006] A discharge control module is provided, wherein the control terminal of the discharge control module is connected to the first connection terminal of the charge / discharge module, the input terminal of the discharge control module is connected to the control electrode of the switching transistor, and the output terminal of the discharge control module is connected to the main power ground of the main power circuit where the switching transistor is located. The discharge control module is used to turn on when the second potential is output at the drive output terminal, providing a second discharge path from the control electrode of the switching transistor to the main power ground.

[0007] Optionally, the charging and discharging module includes: a first impedance unit, a second impedance unit, and a switching unit;

[0008] The first end of the first impedance unit is the first connection end of the charging and discharging module, and the second end of the first impedance unit is the second connection end of the charging and discharging module;

[0009] The first end of the switching unit is connected to the first end of the first impedance unit, the second end of the switching unit is connected to the first end of the second impedance unit, and the second end of the second impedance unit is connected to the second end of the first impedance unit.

[0010] Optionally, the first impedance unit includes: a first resistor, wherein a first end of the first resistor is a first end of the first impedance unit, and a second end of the first resistor is a second end of the first impedance unit;

[0011] The switching unit includes: a diode; the first electrode of the diode is the first terminal of the switching unit, and the second electrode of the diode is the second terminal of the switching unit;

[0012] The second impedance unit includes: a second resistor; the first end of the second resistor is the first end of the second impedance unit, and the second end of the second resistor is the second end of the second impedance unit.

[0013] Optionally, the discharge control module includes: a first transistor; the control terminal of the first transistor is the control terminal of the discharge control module, the first terminal of the first transistor is connected to the input terminal of the discharge control module, and the second terminal of the first transistor is connected to the output terminal of the discharge control module.

[0014] Optionally, the discharge control module further includes a third resistor, the first end of which is the input terminal of the discharge control module, and the second end of which is connected to the first electrode of the first transistor.

[0015] Optionally, the input terminal of the discharge control module is connected to the second terminal of the switching unit;

[0016] The discharge control module includes: a second transistor; the control terminal of the second transistor is the control terminal of the discharge control module, the first terminal of the second transistor is the input terminal of the discharge control module, and the second terminal of the second transistor is the output terminal of the discharge control module.

[0017] Optionally, the switching transistor drive circuit further includes: a voltage divider module, wherein the first end of the voltage divider module is connected to the control electrode of the switching transistor, and the second end of the voltage divider module is connected to the main power ground; the voltage divider module is used to cooperate with the charging and discharging module to divide the voltage connected to the first connection terminal of the charging and discharging module.

[0018] Optionally, the switching transistor drive circuit further includes: a filtering module, wherein a first end of the filtering module is connected to the control electrode of the switching transistor, and a second end of the filtering module is connected to the main power ground.

[0019] Optionally, the filtering module includes a capacitor and a fourth resistor; the first terminal of the capacitor is the first terminal of the filtering module, the second terminal of the capacitor is connected to the first terminal of the fourth resistor, and the second terminal of the fourth resistor is the second terminal of the filtering module.

[0020] Secondly, this utility model embodiment also provides a power conversion device, including: a controller, a driver chip, a main power circuit, and the aforementioned switching transistor driver circuit;

[0021] The main power circuit includes a switching transistor and a main power ground. The switching transistor driving circuit is connected to the driving output terminal of the driving chip, the control electrode of the switching transistor, and the main power ground, respectively.

[0022] The signal input terminal of the driver chip is connected to the drive control terminal of the controller. The first power supply terminal of the driver chip is connected to the power supply voltage, and the second power supply terminal of the driver chip serves as the driver chip ground. The driver chip is used to control the first power supply terminal or the second power supply terminal to connect to the drive output terminal according to the signal connected to the signal input terminal.

[0023] In the switching transistor driving circuit provided in this embodiment, a discharge control module is added to the existing charging and discharging module. By controlling the discharge control module to conduct when the second potential is output at the drive output terminal of the driver chip, a second discharge path from the control electrode of the switching transistor to the main power ground is added when the control electrode of the switching transistor discharges. This accelerates the discharge of the control electrode of the switching transistor, enabling the switching transistor to operate quickly. Furthermore, since the second discharge path leads to the main power ground, it is shorter than the first discharge path to the driver chip. Compared to only having a first discharge path, this avoids the discharge effect being affected by an excessively long discharge path, and prevents drive oscillations or interference caused by an excessively long discharge path. Therefore, this embodiment of the invention can improve the reliability of the switching transistor drive control.

[0024] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this utility model, nor is it intended to limit the scope of this utility model. Other features of this utility model will become readily apparent from the following description. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is an equivalent circuit diagram of a switching transistor;

[0027] Figure 2 This is a schematic diagram of a switching transistor driving circuit provided in an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of another switching transistor driving circuit provided in this embodiment of the utility model;

[0029] Figure 4 This is a schematic diagram of another switching transistor driving circuit provided in this embodiment of the utility model;

[0030] Figure 5 This is a schematic diagram of another switching transistor driving circuit provided in this embodiment of the utility model;

[0031] Figure 6 This is a schematic diagram of another switching transistor driving circuit provided in this embodiment of the utility model;

[0032] Figure 7 This is a schematic diagram of the structure of a power conversion device provided in an embodiment of this utility model. Detailed Implementation

[0033] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0034] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0035] This utility model embodiment provides a switching transistor driving circuit, which helps to improve the reliability of switching transistor driving control. For ease of explanation, the following first combines... Figure 1 The equivalent circuit of the switching transistor is explained.

[0036] Figure 1 This is an equivalent circuit diagram of a switching transistor. See also... Figure 1 Taking an NMOS transistor as an example, the physical meaning of each part in the equivalent circuit of the switching transistor is as follows:

[0037] (1) LG and RG represent the inductance and resistance of the line from the package terminal of the gate G of the switching transistor to the actual gate, respectively.

[0038] (2) C1 represents the capacitance between the gate G of the switching transistor and the N+ region of the source S. Its value is fixed by the structure.

[0039] (3) C2+C4 represents the capacitance between the gate G and the source S of the switching transistor in the P region; where C2 is the dielectric capacitance, and its value is fixed; C4 is determined by the size of the depletion region from the source S to the drain D, and changes with the magnitude of the gate voltage. When the gate voltage of the switching transistor rises from 0 to the turn-on voltage, the change in C4 will increase the total gate-source capacitance by 10% to 15%.

[0040] (4) C3+C5 consists of a fixed-size dielectric capacitor (i.e., C3) and a variable capacitor (i.e., C5). When the drain voltage of the switching transistor changes polarity, the capacitance value of C5 will become quite large.

[0041] (5) C6 is the drain-source capacitance that varies with the drain voltage of the switching transistor.

[0042] according to Figure 1 In the equivalent circuit shown, the relationship between the input capacitance (Ciss), bridging capacitance (Crss), and output capacitance (Coss) of the switching transistor and the gate-source capacitance (Cgs), gate-drain capacitance (Cgd), and drain-source capacitance (Csd) is as follows:

[0043] Ciss = Cgs + Cgd ≈ C1 + C4 + C5;

[0044] Crss=Cgd≈C5;

[0045] Coss = Cgd + Cds ≈ C5 + C6.

[0046] Based on the analysis of the equivalent circuit above, the reason for the poor reliability of the switch drive control mentioned in the background art is that when the switch is turned off, the charge on the input capacitor Ciss is not quickly and completely released. In addition, the long discharge path caused by the parallel use of the transistor and the ground potential fluctuation caused by the large current in the main power circuit (or main power loop) result in drive potential jitter. This embodiment of the invention adds a discharge control module, which is equivalent to adding a stable discharge path that can quickly release the charge on the input capacitor Ciss, thereby improving the reliability of the switch drive control. The switch drive circuit provided in this embodiment of the invention will be described in detail below.

[0047] Figure 2 This is a schematic diagram of a switching transistor driving circuit provided in an embodiment of this utility model. See also... Figure 2 The switching transistor drive circuit 100 includes a charging / discharging module 10 and a discharging control module 20.

[0048] The charging / discharging module 10 has a first connection terminal N1 connected to the drive output terminal b1 of the driver chip 200, and a second connection terminal N2 connected to the control electrode G1 of the switch Q. The charging / discharging module 10 provides a charging path to the control electrode G1 of the switch Q when the drive output terminal b1 outputs a first potential, and provides a first discharging path from the control electrode G1 of the switch Q to the driver chip 200 when the drive output terminal b1 outputs a second potential. The first potential and the second potential are different; for example, one may be the turn-on voltage of the switch Q, and the other may be the turn-off voltage of the switch Q. The control terminal N3 of the discharge control module 20 is connected to the first connection terminal N1 of the charge / discharge module 10, that is, connected to the drive output terminal b1 of the driver chip 200; the input terminal N4 of the discharge control module 20 is connected to the control electrode G1 of the switch Q, and the output terminal N5 of the discharge control module 20 is connected to the main power ground GND1 of the main power circuit where the switch Q is located; the discharge control module 20 is used to turn on when the drive output terminal b1 outputs the second potential, providing a second discharge path from the control electrode G1 of the switch Q to the main power ground GND1.

[0049] For example, the switch Q can be a semiconductor switch, specifically a MOS transistor. In this case, the control electrode G1 of the switch Q is its gate, the first electrode S1 is its source, and the second electrode D1 is its drain. For example, the switch Q can be an NMOS transistor. The switch Q is a switching device constituting the main power circuit. The connection relationship between the first electrode S1 and the second electrode D1 of the switch Q in the main power circuit can be set according to its function. For example, the first electrode S1 can be connected to the main power ground GND1 or to other components in the main power circuit, without specific limitations here. The main power circuit is a circuit in the power conversion device used for energy conversion. For example, when the power conversion device is an energy storage inverter, the main power circuit is an energy transmission channel used to realize the mutual conversion of DC power and AC power. The main power circuit may include multiple switches Q. The controller and driver chip 200 are control components in the power conversion device. For example, the energy conversion function of the main power circuit is realized by controlling the on and off states of each switch Q. The control electrode G1 of the switch Q is connected to the drive output terminal b1 of the driver chip 200 through the switch drive circuit 100.

[0050] The driver chip 200 can be an isolated driver chip. In the driver chip 200, the signal input terminal a1 can be connected to the drive control terminal DR of the controller, the first power supply terminal VCC can be connected to a DC power supply voltage, and the second power supply terminal GND serves as the driver chip ground. For example, the second power supply terminal GND can be connected to a ground different from the main power ground GND1 to achieve isolation between the driver chip ground and the main power ground GND1. Alternatively, the second power supply terminal GND can also be... Figure 2 The dashed line indicates a connection to the main power ground GND1 to ensure consistency of ground signals across different components. The driver chip 200 provides high and low levels for turning the switch Q on and off via its driver output terminal b1. Typically, the voltage level output from the controller's drive control terminal DR is low, for example, 3.3V, insufficient to drive the switch Q. Therefore, the driver chip 200 is configured to convert the voltage output from the drive control terminal DR to obtain a sufficient drive signal to operate the switch Q. For example, the first potential is the power supply voltage connected to the first power supply terminal VCC, and the second potential is the ground signal connected to the second power supply terminal GND; the first potential is higher than the second potential. The driver chip 200 can control the connection between its first power supply terminal VCC or its second power supply terminal GND and the driver output terminal b1 based on the signal output from the controller's drive control terminal DR, thereby controlling the potential output by the driver output terminal b1.

[0051] For example, the charge / discharge module 10 may include at least an impedance element to limit the charge / discharge current of the control electrode G1 of the switch Q.

[0052] The discharge control module 20 may include controllable switching elements, such as transistors or relays, to turn on or off according to the potential output from the drive output terminal b1.

[0053] The specific operation of the switching transistor drive circuit 100 can include:

[0054] Charging process: The drive output terminal b1 outputs the first potential, and the power supply voltage of the first power supply terminal VCC charges the control electrode G1 of the switching transistor Q through the charging path formed by the charging and discharging module 10; at this time, the discharge control module 20 responds to the first potential and cuts off, which does not affect the charging process of the control electrode G1.

[0055] Discharge process: The drive output terminal b1 outputs a second potential. In this case, on the one hand, the control electrode G1 of the switch Q discharges to the driver chip ground through the first discharge path formed by the charge / discharge module 10; on the other hand, the discharge control module 20 responds to the second potential and conducts, and the control electrode G1 of the switch Q also discharges through the second discharge path formed by the discharge control module 20. Therefore, this embodiment is equivalent to adding a second discharge path on the basis of the first discharge path, which can accelerate the discharge speed of the input capacitor of the switch Q, avoid voltage glitches generated during discharge as much as possible, and thus improve the stability of the drive control of the switch Q.

[0056] In the switch-driven circuit 100 provided in this embodiment, a discharge control module 20 is added to the existing charging / discharging module 10. By controlling the discharge control module 20 to conduct when the drive output terminal b1 of the drive chip 200 outputs a second potential, a second discharge path is added from the control electrode G1 of the switch Q to the main power ground GND1 during discharge. This accelerates the discharge of the control electrode G1 of the switch Q, enabling the switch Q to operate quickly. Furthermore, since the second discharge path to the main power ground GND1 is shorter than the first discharge path to the drive chip 200, it avoids the discharge effect being affected by an excessively long discharge path, and prevents drive oscillations or interference caused by an excessively long discharge path. Therefore, this embodiment can improve the reliability of the switch-driven control.

[0057] Understandably, when the switch Q is an N-type switch (e.g., NMOS), the first potential is the turn-on voltage, and the second potential is the turn-off voltage. By turning on the discharge control module 20 during discharge, the turn-off of the N-type switch can be accelerated, preventing it from being falsely turned on due to voltage spikes. When the switch Q is a P-type switch, the first potential is the turn-off voltage, and the second potential is the turn-on voltage. By turning on the discharge control module 20 during discharge, the turn-on of the P-type switch can be accelerated, preventing it from being falsely turned off due to voltage spikes. In summary, this switch drive circuit can be applied to corresponding types of switches as needed. By providing a short discharge path connected to the main power ground GND1, the discharge rate of the control electrode G1 of the switch Q is increased, ensuring the discharge effect and thus improving the reliability of the drive control of the switch Q.

[0058] The specific structure of the switching transistor drive circuit is described below by way of example, but it is not intended to limit the present invention.

[0059] Figure 3 This is a schematic diagram of another switching transistor driving circuit provided in an embodiment of this utility model. See also... Figure 3 In one embodiment, optionally, the charging / discharging module 10 includes: a first impedance unit 11, a second impedance unit 12, and a switching unit 13. The first impedance unit 11 is connected between the first connection terminal N1 and the second connection terminal N2 of the charging / discharging module 10, that is, connected between the drive output terminal b1 and the control electrode G1 of the switching transistor Q. Specifically, the first end of the first impedance unit 11 is the first connection terminal N1 of the charging / discharging module 10, and the second end of the first impedance unit 11 is the second connection terminal N2 of the charging / discharging module 10. The switching unit 13 and the second impedance unit 12 are connected in series between the first connection terminal N1 and the second connection terminal N2 of the charging / discharging module 10, that is, connected in series between the drive output terminal b1 and the control electrode G1 of the switching transistor Q. Specifically, the first end of the switching unit 13 is connected to the first end of the first impedance unit 11, the second end of the switching unit 13 is connected to the first end of the second impedance unit 12, and the second end of the second impedance unit 12 is connected to the second end of the first impedance unit 11.

[0060] It should be noted that, as Figure 3 As shown, an example is provided where the switch unit 13 is disposed near the first connection terminal N1 and the second impedance unit 12 is disposed near the second connection terminal N2. However, this is not intended to limit the present invention. In other embodiments, the positions of the second impedance unit 12 and the switch unit 13 can be interchanged as needed.

[0061] In this charging and discharging module 10, the equivalent impedance of the charging and discharging module 10 can be adjusted by controlling the on / off state of the switching unit 13, thereby affecting the charging and discharging rate of the control electrode G1 of the switching transistor Q. Specifically, when the switching unit 13 is off, the equivalent impedance of the charging and discharging module 10 is the impedance value of the first impedance unit 11; when the switching unit 13 is on, the equivalent impedance of the charging and discharging module 10 is the parallel impedance value of the first impedance unit 11 and the second impedance unit 12, which is less than the equivalent impedance of the charging and discharging module 10 when the switching unit 13 is off.

[0062] For example, the switching unit 13 can be configured to turn on when the drive output terminal b1 outputs a first potential and turn off when the drive output terminal b1 outputs a second potential, so that the impedance of the charging path is less than the impedance of the first discharging path, thus forming a fast-charging circuit. For example, without considering the role of the discharge control module 20, a fast-charging slow-discharging drive circuit can be formed based on the charge-discharge module 10, which is particularly suitable for driving the switching transistor Q in a main power circuit with a small current, such as a main power circuit with a flyback circuit structure. Adding the discharge control module 20 on this basis can form a fast-charging fast-discharging drive circuit, which can realize both fast charging and fast discharging, and comprehensively improve the operating performance of the switching transistor Q.

[0063] Alternatively, the switching unit 13 can be configured to turn off when the drive output terminal b1 outputs the first potential and turn on when the drive output terminal b1 outputs the second potential, making the impedance of the charging path greater than the impedance of the first discharging path. This can form a slow-charge, fast-discharge circuit, which is especially suitable for driving the switching transistor Q in main power circuits with small to medium current. Adding a discharge control module 20 on this basis can further improve the discharge rate.

[0064] In summary, the on / off rules of the switch unit 13 can be configured according to actual needs to adapt to actual application scenarios.

[0065] Specifically, Figure 4 This is a schematic diagram of another switching transistor driving circuit provided in an embodiment of this utility model. See also... Figure 4 The first impedance unit 11 includes a first resistor R1, which is connected between the first connection terminal N1 and the second connection terminal N2 of the charging / discharging module 10. Specifically, the first end of the first resistor R1 is the first end of the first impedance unit 11, and the second end of the first resistor R1 is the second end of the first impedance unit 11. This configuration makes the structure of the first impedance unit 11 simple and easy to implement.

[0066] The switching unit 13 includes a diode D1; the second impedance unit 12 includes a second resistor R2. Diode D1 and the second resistor R2 are connected in series between the first connection terminal N1 and the second connection terminal N2 of the charging / discharging module 10. Specifically, the first electrode of diode D1 is the first terminal of the switching unit 13, the second electrode of diode D1 is the second terminal of the switching unit 13, the first terminal of the second resistor R2 is the first terminal of the second impedance unit 12, and the second terminal of the second resistor R2 is the second terminal of the second impedance unit 12. For example, as... Figure 4 As shown, the first terminal of diode D1 can be the anode, and the second terminal can be the cathode. Alternatively, the first terminal of diode D1 can be the cathode, and the second terminal can be the anode. Preferably, as shown... Figure 4 The structure shown is designed to implement a fast-charge and fast-discharge drive circuit.

[0067] Based on the above embodiments, there are several possible ways to connect the discharge control module 20 to the control electrode G1 of the switching transistor Q. Several of these methods will be described by example below.

[0068] In one implementation, optionally, see [link to relevant documentation]. Figure 3 and Figure 4 The input terminal N4 of the discharge control module 20 is directly connected to the control electrode G1 of the switching transistor Q to achieve direct discharge control. This configuration allows the second discharge path to exist independently of other paths, enabling direct control of the discharge at the control electrode G1.

[0069] For details, see Figure 4 The discharge control module 20 includes: a first transistor Q1; the control terminal of the first transistor Q1 is the control terminal N3 of the discharge control module 20, which is connected to the first connection terminal N1 of the charge / discharge module 10; the first terminal of the first transistor Q1 is connected to the input terminal N4 of the discharge control module 20, and then connected to the control terminal G1 of the switching transistor Q; the second terminal of the first transistor Q1 is the output terminal N5 of the discharge control module 20, which is connected to the main power ground GND1. For example, the first transistor Q1 can be a transistor, specifically a PNP transistor, or other types of controllable transistors.

[0070] Further, see Figure 4The discharge control module 20 may further include a third resistor R3, which is connected between the control electrode G1 of the switch Q and the first electrode of the first transistor Q1. The first end of the third resistor R3 serves as the input terminal N4 of the discharge control module 20, and the second end is connected to the first electrode of the first transistor Q1. This provides a second discharge path with an adjustable discharge rate. Specifically, when only the first transistor Q1 is used, its first electrode is directly connected to the input terminal N4 of the discharge control module 20. The control electrode G1 of the switch Q discharges rapidly through the conducting first transistor Q1, potentially causing a high voltage spike in the switch Q. By adding the third resistor R3 as a current-limiting resistor in the second discharge path, the discharge current in the second discharge path can be limited, preventing voltage spikes. The resistance value of the third resistor R3 can be adjusted according to actual current-limiting requirements, allowing the discharge rate of the input capacitor Ciss of the switch Q to be adjusted according to the actual application scenario, enhancing the applicability of the switch drive circuit 100.

[0071] Figure 5 This is a schematic diagram of another switching transistor driving circuit provided in this embodiment of the utility model; Figure 6 This is a schematic diagram of another switching transistor driving circuit provided in an embodiment of the present invention. Alternatively, see [link to another embodiment]. Figure 5 and Figure 6 The discharge control module 20 can be indirectly connected to the control electrode G1 of the switch Q through an impedance element connected to the control electrode G1 of the switch Q, so as to reuse the impedance element to limit the discharge current on the second discharge path, and simplify the circuit structure by reusing the impedance element.

[0072] For example, such as Figure 5 and Figure 6 As shown, the input terminal N4 of the discharge control module 20 can be connected to the connection node N6 between the switching unit 13 and the second impedance unit 12, that is, the second terminal of the switching unit 13, so that the second impedance unit 12 is reused as the current limiting unit on the second discharge path.

[0073] For details, see Figure 6The discharge control module 20 includes: a second transistor Q2; a control terminal N3 of the second transistor Q2, connected to the first connection terminal N1 of the charge / discharge module 10; a first terminal N4 of the second transistor Q2, connected to the connection node N6 between the switching unit 13 and the second impedance unit 12; and a second terminal N5 of the second transistor Q2, connected to the main power ground GND1. For example, the second transistor Q2 can be a transistor, specifically a PNP transistor, or other types of controllable transistors.

[0074] It should be noted that, Figure 6 In the switch driver circuit 100 shown, the charging path and the second discharging path share the second resistor R2. Due to limitations on the charging rate, the resistance value of the second resistor R2 cannot be adjusted over a wide range. Especially when the switch Q requires slow charging, a larger resistance value is needed for the second resistor R2, which limits fast discharging and also affects the flexibility of debugging EMI (Electromagnetic Interference) and stress. Therefore, it is preferable to use... Figure 4 The direct connection circuit structure shown is designed to improve circuit flexibility and adjustability.

[0075] See also Figure 4 and Figure 6 Based on the above embodiments, optionally, the switch driving circuit 100 further includes a voltage divider module 30, which is connected between the control electrode G1 of the switch Q and the main power ground GND1. Specifically, the first end of the voltage divider module 30 is connected to the control electrode G1 of the switch Q, and the second end of the voltage divider module 30 is connected to the main power ground GND1. The voltage divider module 30 is used in conjunction with the charging / discharging module 10 to divide the voltage connected to the first connection terminal N1 of the charging / discharging module 10. The voltage divider module 30 mainly functions during the charging process, for example. Specifically, the voltage divider module 30 may include a fifth resistor R5, which is connected between the control electrode G1 of the switch Q and the main power ground GND1. The first end of the fifth resistor R5 is the first end of the voltage divider module 30, and the second end of the fifth resistor R5 is the second end of the voltage divider module 30.

[0076] See also Figure 4 and Figure 6Based on the above embodiments, the switching transistor drive circuit 100 may optionally further include a filter module 40 connected between the control electrode G1 of the switching transistor Q and the main power ground GND1. Specifically, the first end of the filter module 40 is connected to the control electrode G1 of the switching transistor Q, and the second end of the filter module 40 is connected to the main power ground GND1. The filter module 40 is used to filter the control electrode G1 of the switching transistor Q to improve the stability of the voltage of the control electrode G1, for example, mainly filtering out high-order oscillation harmonics.

[0077] Specifically, the filter module 40 includes a capacitor C and a fourth resistor R4; capacitor C and fourth resistor R4 are connected in series between the control electrode G1 of the switching transistor Q and the main power ground GND1. Specifically, the first terminal of capacitor C is the first terminal of filter module 40, and the second terminal of capacitor C is connected to the first terminal of fourth resistor R4; the second terminal of fourth resistor R4 is the second terminal of filter module 40. It should be noted that... Figure 4 and Figure 6 The example shows capacitor C connected to the control electrode G1 side of the switching transistor Q and fourth resistor R4 connected to the main power ground GND1 side, but this is not intended to limit the present invention. In other embodiments, the positions of capacitor C and fourth resistor R4 can be interchanged as needed.

[0078] In summary, the switching transistor driving circuit provided by this embodiment of the invention has the following effects:

[0079] 1. By setting the discharge control module 20 to form a second discharge path, the discharge of the switching transistor Q can be accelerated, enabling the switching transistor Q to operate quickly and avoiding drive oscillation or interference caused by an excessively long drive circuit; furthermore, by including a current-limiting element in the second discharge path, for example... Figure 4 Add a third resistor R3, or as follows Figure 5 and Figure 6 The reuse of the second impedance unit 12 can prevent excessively fast discharge from causing a high spike voltage in the switching transistor Q; especially when... Figure 4 The addition of a third resistor R3 allows the discharge speed to be adjusted according to the actual application scenario, enhancing its applicability.

[0080] 2. For some main power circuit topologies with upper and lower transistors connected, the switching transistor drive circuit 100 can improve the operating speed of the switching transistor Q (e.g., improve the turn-off speed of the NMOS transistor), thereby shortening the dead time of the upper and lower transistors, reducing the input peak current, thus optimizing the EMI of the whole machine and improving the overall efficiency.

[0081] 3. For applications where the main power circuit is a high-current loop, such as a low-voltage battery boost circuit, where the peak current on the low-voltage side is 500A or more, the switching transistor drive circuit 100 can be used to reduce the drive interference caused by the large voltage difference between the driver chip ground and the main power ground GND1 due to the excessively long drive trace between the driver chip and the driver chip 200.

[0082] 4. For scenarios involving multiple parallel transistors, based on Figure 4 The switch drive circuit 100 shown has adjustable impedance for each component, providing a good optimization method for stress, EMI, and performance balancing. In particular, adjusting the third resistor R3 alone only affects the discharge rate and does not interfere with the charging path.

[0083] The following is based on Figure 4 The switching transistor driving circuit 100 shown, and taking the switching transistor Q as an NMOS transistor as an example, the operation process of the switching transistor driving circuit 100 includes:

[0084] 1) Turn-on process of switch Q: The drive output terminal b1 outputs a first potential (e.g., a high level), the first transistor Q1 is not conducting, and the first resistor R1, diode D1, second resistor R2, and fifth resistor R5 form a voltage divider. Capacitor C and fourth resistor R4 are used to filter out high-order oscillation harmonics. Since diode D1 is conducting, the first resistor R1 and the second resistor R2 are connected in parallel as an external input resistor, forming a charging path. This turn-on process is the process of charging the control electrode G1 of switch Q, that is, the process of charging the input capacitor Ciss of switch Q. The impedance on the charging path can limit the turn-on rate; and the charging rate can be adjusted by adjusting the resistance values ​​of the first resistor R1 and the second resistor R2, thereby adjusting the turn-on rate of switch Q.

[0085] 2) Turn-off process of switch Q: The drive output terminal b1 outputs a second potential (e.g., a low level). This turn-off process is the discharge process of the control electrode G1 of switch Q, that is, the discharge process of the input capacitor Ciss of switch Q. During this process, the first transistor Q1 is turned on, and the diode D1 is turned off. Then, the first resistor R1 forms the first discharge path, and the control electrode G1 of switch Q discharges to the driver chip ground through the first discharge path; the third resistor R3 and the first transistor Q1 form the second discharge path, and the control electrode G1 of switch Q also discharges to the main power ground GND1 through the second discharge path.

[0086] Because of the current limitation of the driver chip and to avoid oscillation during the power-on process, the resistance of the first resistor R1 cannot be set too low. Therefore, the first resistor R1 also limits the discharge rate, thus limiting the discharge rate of the first discharge path. Therefore, to increase or decrease the discharge rate, the resistance of the third resistor R3 can be adjusted without affecting the impedance of the charging path. Especially for scenarios using multiple parallel transistors, this switching transistor driver circuit 100 provides an excellent optimization method for balancing stress, EMI, and performance.

[0087] In summary, the charging and discharging rates of this switching transistor drive circuit 100 are adjustable, making it more widely applicable and versatile. It can be used in low-current main power circuit scenarios, high-current switching transistor drive scenarios, parallel and series switching transistor scenarios, and so on.

[0088] This utility model embodiment also provides a power conversion device, including a switching transistor and a switching transistor drive circuit provided in any embodiment of this utility model, which has corresponding beneficial effects.

[0089] Figure 7 This is a schematic diagram of the structure of a power conversion device provided in an embodiment of this utility model. See also... Figure 7 The power conversion device includes: a controller 300, a driver chip 200, a main power circuit 400, and a switching transistor driver circuit 100. The main power circuit 400 includes a switching transistor Q and a main power ground GND1. The switching transistor driver circuit 100 is connected to the drive output terminal b1 of the driver chip 200, the control terminal G1 of the switching transistor Q, and the main power ground GND1. It should be noted that... Figure 7 The example provided illustrates a direct connection of the switching transistor Q to the main power ground GND1, but this is not intended to limit the invention. When the main power circuit 400 includes multiple switching transistors, the switching transistor Q can be any one of the transistors in the main power circuit 400, and the actual connection relationship is determined according to the actual topology. For example, each switching transistor Q in the main power circuit 400 is provided with its own corresponding switching transistor drive circuit 100 to achieve good charge and discharge control for each switching transistor Q, ensuring the stability of the device operation. Furthermore, when there is a scenario where switching transistors are used in parallel, the switching transistor drive circuits 100 of each parallel-driven switching transistor Q can be connected to the same drive chip 200.

[0090] The signal input terminal a1 of the driver chip 200 is connected to the drive control terminal DR of the controller 300. The first power supply terminal VCC of the driver chip 200 is connected to the power supply voltage, and the second power supply terminal GND of the driver chip 200 serves as the driver chip ground. The driver chip 200 is used to control the connection between the first power supply terminal VCC or the second power supply terminal GND and the drive output terminal b1 according to the signal input terminal a1, thereby controlling the output potential of the drive output terminal b1. The driver chip ground can be isolated from or connected to the main power ground GND1, depending on the actual requirements.

[0091] For example, the power conversion device can be an energy storage inverter, such as a residential energy storage inverter. The main power circuit 400 is a functional component in the power conversion device used for energy conversion; the controller 300, the driver chip 200, and the switching transistor drive circuit 100 are control components in the power conversion device. The switching transistor Q is a semiconductor switching transistor, specifically a MOSFET, and more specifically an NMOS transistor.

[0092] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A switching transistor driving circuit, characterized in that, include: A charging and discharging module, wherein the first connection terminal of the charging and discharging module is used to connect to the drive output terminal of the driver chip, and the second connection terminal of the charging and discharging module is connected to the control electrode of the switching transistor; The charging and discharging module is used to provide a charging path for charging the control electrode of the switching transistor when the first potential is output at the drive output terminal, and to provide a first discharging path for discharging the control electrode of the switching transistor to the drive chip when the second potential is output at the drive output terminal. The first potential is different from the second potential; A discharge control module is provided, wherein the control terminal of the discharge control module is connected to the first connection terminal of the charge / discharge module, the input terminal of the discharge control module is connected to the control electrode of the switching transistor, and the output terminal of the discharge control module is connected to the main power ground of the main power circuit where the switching transistor is located. The discharge control module is used to turn on when the second potential is output at the drive output terminal, providing a second discharge path from the control electrode of the switching transistor to the main power ground.

2. The switching transistor driving circuit according to claim 1, characterized in that, The charging and discharging module includes: a first impedance unit, a second impedance unit, and a switching unit; The first end of the first impedance unit is the first connection end of the charging and discharging module, and the second end of the first impedance unit is the second connection end of the charging and discharging module; The first end of the switching unit is connected to the first end of the first impedance unit, the second end of the switching unit is connected to the first end of the second impedance unit, and the second end of the second impedance unit is connected to the second end of the first impedance unit.

3. The switching transistor driving circuit according to claim 2, characterized in that, The first impedance unit includes: a first resistor, wherein a first end of the first resistor is a first end of the first impedance unit, and a second end of the first resistor is a second end of the first impedance unit; The switching unit includes: a diode; the first electrode of the diode is the first terminal of the switching unit, and the second electrode of the diode is the second terminal of the switching unit; The second impedance unit includes: a second resistor; the first end of the second resistor is the first end of the second impedance unit, and the second end of the second resistor is the second end of the second impedance unit.

4. The switching transistor drive circuit according to any one of claims 1-3, characterized in that, The discharge control module includes: a first transistor; the control terminal of the first transistor is the control terminal of the discharge control module, the first terminal of the first transistor is connected to the input terminal of the discharge control module, and the second terminal of the first transistor is connected to the output terminal of the discharge control module.

5. The switching transistor driving circuit according to claim 4, characterized in that, The discharge control module further includes a third resistor, the first end of which is the input terminal of the discharge control module, and the second end of which is connected to the first electrode of the first transistor.

6. The switching transistor driving circuit according to claim 2 or 3, characterized in that, The input terminal of the discharge control module is connected to the second terminal of the switching unit; The discharge control module includes: a second transistor; the control terminal of the second transistor is the control terminal of the discharge control module, the first terminal of the second transistor is the input terminal of the discharge control module, and the second terminal of the second transistor is the output terminal of the discharge control module.

7. The switching transistor driving circuit according to claim 1, characterized in that, Also includes: A voltage divider module is provided, wherein the first end of the voltage divider module is connected to the control electrode of the switching transistor, and the second end of the voltage divider module is connected to the main power ground; the voltage divider module is used in conjunction with the charging and discharging module to divide the voltage connected to the first connection terminal of the charging and discharging module.

8. The switching transistor driving circuit according to claim 1, characterized in that, Also includes: A filtering module, wherein the first end of the filtering module is connected to the control electrode of the switching transistor, and the second end of the filtering module is connected to the main power ground.

9. The switching transistor driving circuit according to claim 8, characterized in that, The filtering module includes a capacitor and a fourth resistor; the first end of the capacitor is the first end of the filtering module, the second end of the capacitor is connected to the first end of the fourth resistor, and the second end of the fourth resistor is the second end of the filtering module.

10. A power conversion device, characterized in that, include: The controller, driver chip, main power circuit, and switching transistor driver circuit as described in any one of claims 1-9; The main power circuit includes a switching transistor and a main power ground. The switching transistor driving circuit is connected to the driving output terminal of the driving chip, the control electrode of the switching transistor, and the main power ground, respectively. The signal input terminal of the driver chip is connected to the drive control terminal of the controller. The first power supply terminal of the driver chip is connected to the power supply voltage, and the second power supply terminal of the driver chip serves as the driver chip ground. The driver chip is used to control the first power supply terminal or the second power supply terminal to connect to the drive output terminal according to the signal connected to the signal input terminal.

Images