Current-mode driver for wide-band-gap semiconductor transistor and driving method thereof

Abstract

The invention discloses a current-mode driver and a driving method for a wide-band-gap semiconductor transistor. The current-mode driver includes an input pin receiving a switching control signal, a power pin coupled to a power supply, and first and second output pins coupled to a gate of the wide bandgap semiconductor transistor. In response to a first state of the switching control signal, the current-mode driver first provides a first constant current through the second output pin and then switches to provide a second constant current to drive the wide bandgap semiconductor transistor. In response to a second state of the switching control signal, the current-mode driver pulls down the gate of the wide bandgap semiconductor transistor through the first output pin.

Description

Technical Field

[0001] Embodiments of the present invention relate to an electronic circuit, and more particularly, to a driver for a wide bandgap semiconductor transistor. Background Art

[0002] Generally, the conductivity between the drain and source of a field effect transistor made of silicon material is controlled by the voltage applied between its gate and source. The field effect transistor can be driven by a voltage type driver. The voltage type driver can turn on the field effect transistor in a voltage sinking manner or turn off the field effect transistor in a voltage sourcing manner. When being driven, the way the gate of the field effect transistor absorbs and releases charges can be modeled as a capacitor.

[0003] Wide bandgap materials, such as gallium nitride (GaN), can be used to fabricate faster normally-off field effect transistors using a variety of different epitaxial structures or combinations. GaN high electron mobility transistors (HEMTs) can be applied in different architectures, such as cascading HEMTs and metal oxide semiconductor field effect transistors (MOSFETs) made of silicon material, enhancement-mode HEMTs, gate injection transistors (GITs), and so on. For HEMTs cascaded with MOSFETs made of silicon material, their gates are as easy to drive as those of MOSFETs made of silicon material, but the overall performance is more superior. However, when the gate voltage is higher than the forward voltage of the equivalent diode between the gate and the channel, gate leakage current is injected into the semiconductor device. This injection of gate leakage current may cause current collapse phenomenon, resulting in threshold voltage Vth drift and on-resistance Ron degradation. GITs solve the current collapse problem through hole injection. The gates of GITs have ohmic characteristics and have good overvoltage resistance due to the self-clamping characteristics of the equivalent diode between their gates and channels. However, the additional current consumption makes it difficult to drive. Therefore, different drivers need to be designed for enhancement-mode HEMTs and GITs. Summary of the Invention

[0004] To solve the above technical problems, embodiments of the present invention disclose a current type driver for a wide bandgap semiconductor transistor and a driving method.

[0005] According to an embodiment of the present invention, a current-mode driver for a wide-bandgap semiconductor transistor is provided, including: an input terminal configured to receive a switch control signal; an output terminal coupled to the gate of the wide-bandgap semiconductor transistor; a turn-on circuit coupled to the output terminal, the turn-on circuit providing a gate current flowing into the gate of the wide-bandgap semiconductor transistor through the output terminal in response to a first state of the switch control signal to drive the wide-bandgap semiconductor transistor; and a turn-off circuit coupled to the output terminal, the turn-off circuit pulling down the gate of the wide-bandgap semiconductor transistor and turning off the wide-bandgap semiconductor transistor in response to a second state of the switch control signal; wherein when the switch control signal changes to the first state, the turn-on circuit first drives the wide-bandgap semiconductor transistor with a first constant current and then drives the wide-bandgap semiconductor transistor with a second constant current less than the first constant current.

[0006] According to an embodiment of the present invention, a driving method for a wide-bandgap semiconductor transistor is also provided, including: receiving a switch control signal; providing a first constant current to the gate of the wide-bandgap semiconductor transistor in response to a first state of the switch control signal to turn on the wide-bandgap semiconductor transistor; automatically switching to providing a second constant current lower than the first constant current to the gate of the wide-bandgap semiconductor transistor after the gate voltage of the wide-bandgap semiconductor transistor rises to a maximum value to control the wide-bandgap semiconductor transistor to remain turned on; and pulling down the gate of the wide-bandgap semiconductor transistor in response to a second state of the switch control signal to turn off the wide-bandgap semiconductor transistor.

[0007] According to an embodiment of the present invention, a current-mode driver is also provided, including: an input pin configured to receive a switch control signal; a power pin configured to be coupled to a power supply; and a first output pin and a second output pin, the first output pin and the second output pin being commonly coupled to the gate of the wide-bandgap semiconductor transistor; wherein in response to a first state of the switch control signal, the current-mode driver first provides a first constant current through the second output pin and then switches to providing a second constant current through the second output pin to drive the wide-bandgap semiconductor transistor; and in response to a second state of the switch control signal, the current-mode driver pulls down the gate of the wide-bandgap semiconductor transistor through the first output pin. Description of the Drawings

[0008] For a better understanding of the present invention, the present invention will be described in detail with reference to the following drawings. Among them, the same or similar elements include the same reference numerals. Among them, the same elements include the same reference numerals. The following drawings are for illustration only and are not necessarily drawn to scale.

[0009] Figure 1 Shows a block diagram of a current - type driver 10 according to an embodiment of the present invention;

[0010] Figure 2 Shows a schematic diagram of a current - type driver 20 according to an embodiment of the present invention;

[0011] Figure 3 Shows a timing diagram 300 for driving a wide - bandgap semiconductor transistor 14 according to an embodiment of the present invention;

[0012] Figure 4 Shows a schematic diagram of a current - type driver 40 according to an embodiment of the present invention;

[0013] Figure 5 Shows a schematic diagram of a current - type driver 50 according to an embodiment of the present invention;

[0014] Figure 6 Shows a schematic diagram of a current - type driver 60 according to an embodiment of the present invention;

[0015] Figure 7 Shows a driving method 700 for a wide - bandgap semiconductor transistor according to an embodiment of the present invention. Detailed Description of the Invention

[0016] The specific embodiments of the present invention will be described in detail below. It should be noted that the embodiments described here are only for illustrative purposes and do not limit the present invention. In the following description, in order to provide a thorough understanding of the present invention, a large number of specific details are set forth. However, it will be apparent to those of ordinary skill in the art that the present invention does not have to be practiced with these specific details. In other instances, well - known circuits, materials, or methods have not been specifically described to avoid obscuring the present invention.

[0017] Throughout the specification, references to "one embodiment", "an embodiment", "one example", or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present invention. Thus, the phrases "in one embodiment", "in an embodiment", "one example", or "an example" appearing throughout the specification do not necessarily all refer to the same embodiment or example. Additionally, specific features, structures, or characteristics may be combined in any suitable combination and / or sub - combination in one or more embodiments or examples. Moreover, those of ordinary skill in the art should understand that the drawings provided herein are for illustrative purposes only and are not necessarily drawn to scale. Identical reference numerals indicate identical elements. The term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0018] Figure 1A block diagram of a current-mode driver 10 according to an embodiment of the present invention is shown. The current-mode driver 10 drives a wide-bandgap (WBG) semiconductor transistor 14 by providing a gate current Ig flowing into the gate 101 of the WBG semiconductor transistor 14. The WBG semiconductor transistor 14 has a gate 101, a drain 102, and a source 103. As Figure 1 shown, the current-mode driver 10 has an input terminal 11, an output terminal 15, a turn-on circuit 12, and a turn-off circuit 13. The input terminal 11 receives a switch control signal PWM. The current-mode driver 10 turns on and off the WBG semiconductor transistor 14 based on the switch control signal PWM. For example, when the switch control signal PWM is in a first state (such as logic high), the current-mode driver 10 turns on the WBG semiconductor transistor 14 through the turn-on circuit 12, for example, pulling up the gate 101 to form a channel between the drain 102 and the source 102 of the WBG semiconductor transistor 14. When the switch control signal PWM is in a second state (such as logic low), the current-mode driver 10 turns off the WBG semiconductor transistor 14 through the turn-off circuit 13, for example, pulling down the gate 101 to turn off the conduction path. In one embodiment, the turn-on circuit 12 is coupled to the gate 101 of the WBG semiconductor transistor 14 to pull up the gate 101 in response to the first state of the switch control signal PWM. The turn-off circuit 13 is coupled to the gate 101 of the WBG semiconductor transistor 14 to pull down the gate 101 in response to the second state of the switch control signal PWM. Those of ordinary skill in the art should also understand that the WBG semiconductor transistor 14 may include different WBG semiconductor materials, such as gallium nitride, silicon carbide, etc.

[0019] In one embodiment, the turn-on circuit 12 drives the gate 101 of the WBG semiconductor transistor 14 with a first constant current to achieve fast turn-on of the WBG semiconductor transistor 14, and then automatically switches to driving the gate 101 of the WBG semiconductor transistor 14 with a second constant current. The second constant current is lower than the first constant current. The WBG semiconductor transistor 14 remains on under the drive of the second constant current while having a lower gate power consumption. In one embodiment, the first constant current and the second constant current are set by the user (for example, through external components such as resistors) to better adapt to the gate requirements of different transistor pairs. The switching between the first constant current and the second constant current will occur automatically without user intervention.

[0020] In Figure 1In the illustrated embodiment, the turn-on circuit 12 includes a current transfer circuit 121 and a current monitoring circuit 122. The current transfer circuit 121 is coupled to the power supply VDD and provides a gate current Ig when the wide-bandgap semiconductor transistor 14 is to be turned on. The current monitoring circuit 122 monitors the gate current Ig and provides a current setting signal Iset accordingly. The current setting signal Iset can indicate, for example, whether the gate current Ig has dropped below a first constant current, such as below a current threshold.

[0021] The current transfer circuit 121 receives a switch control signal PWM and a current setting signal Iset, and provides a gate current Ig according to the switch control signal PWM and the current setting signal Iset. In one embodiment, when the switch control signal PWM controls the wide-bandgap semiconductor transistor 14 to turn on, the current transfer circuit 121 first provides a first constant current to drive the gate 101, and then in response to the current setting signal Iset, the current transfer circuit 121 switches to provide a second constant current to drive the gate 101. Thus, a reduction in the gate current Ig and control of the voltage of the gate 101 can be achieved simultaneously.

[0022] Figure 2 A schematic diagram of a current-mode driver 20 according to an embodiment of the present invention is shown. As Figure 2 shown, the current transfer circuit 121A of the current-mode driver 20 uses resistors Rs1 and Rs2 to set the first constant current and the second constant current. In one embodiment, the resistor Rs1 is used to set the first constant current, and the resistor Rs2 is used to set the second constant current that is lower than the first constant current.

[0023] The current transfer circuit 121A further includes a pull-up circuit 21 and a switch S1. When the switch control signal PWM controls the wide-bandgap semiconductor transistor 14 to turn on, the pull-up circuit 21 first pulls up the gate 101 through the resistor Rs1 to establish the first constant current. Until the gate current Ig is lower than the first constant current, the pull-up circuit 21 pulls up the gate 101 through the resistor Rs2 to establish the second constant current. In one embodiment, the pull-up circuit 21 is coupled between the power supply VDD and the resistors Rs1 and Rs2. The switch S1 can be simplified to a single-pole double-throw switch. Under the control of the current setting signal Iset, the switch S1 couples one of the resistors Rs1 and Rs2 to the pull-up circuit 21. Those of ordinary skill in the art should understand that the positions of the pull-up circuit 21, the switch S1, and the resistors Rs1 and Rs2 are not limited by Figure 2 the specific embodiment shown. For example, the resistors Rs1 and Rs2 can be directly coupled to the pull-up circuit 21, and the switch S1 can be coupled between the gate 101 and the resistors Rs1 and Rs2, without diminishing the advantages of the present invention.

[0024] Figure 3FIG. 300 shows a timing diagram for driving a wide bandgap semiconductor transistor 14 according to an embodiment of the present invention. Figure 3 In the illustrated embodiment, the switching control signal PWM, the gate voltage Vgs, the gate current I, and the current setting signal Iset are shown from top to bottom. The gate voltage Vgs is the voltage between the gate 101 and the source 103 of the wide bandgap semiconductor transistor 14.

[0025] At time t1, the switching control signal PWM1 goes high to control the wide bandgap semiconductor transistor 14 to turn on. Figure 2 The illustrated current type driver 20 first pulls up the gate 101 through the resistor Rs1 to turn on the wide bandgap semiconductor transistor 14 and sets the gate current Ig to be equal to the constant current Is1. The gate voltage Vgs increases at a settable slope. When the gate voltage Vgs increases to its maximum value, for example, equal to the power supply VDD minus the voltage drop across the current transfer circuit 121A, the current transfer circuit 121A cannot continue to inject the same current into the gate 101, and the gate current Ig drops from the constant current Is1. Until time t2, when the gate current Ig drops below the threshold Ith, the current setting signal Iset goes high, and the current type driver 20 pulls up the gate 101 through the resistor Rs2, and the gate current Ig is equal to the constant current Is2. The constant current Is2 is significantly smaller than the constant current Is1. In one embodiment, the magnitude of the constant current Is1 is determined by the resistor Rs1, and the magnitude of the constant current Is2 is determined by the resistor Rs2.

[0026] Figure 4 FIG. shows a schematic diagram of a current type driver 40 according to an embodiment of the present invention. The current type driver 40 receives the switching control signal PWM and provides the gate current Ig to the gate 101 of the wide bandgap semiconductor transistor 14. When the switching control signal PWM needs to control the wide bandgap semiconductor transistor 14 to turn on, the turn-on circuit 12A composed of the pull-up circuit 21A, the current monitoring circuit 122A, and the resistors Rs1 - Rs2 provides the gate current Ig to the gate 101 of the wide bandgap semiconductor transistor 14. When the switching control signal PWM needs to control the wide bandgap semiconductor transistor 14 to turn off, the turn-off circuit 13A extracts the gate current Ig from the gate 101 of the wide bandgap semiconductor transistor 14.

[0027] At Figure 4In the illustrated embodiment, the pull-up circuit 21A includes a transistor Q1, a transistor Q2, and a switch S2. In one embodiment, the transistors Q1 and Q2 are bipolar junction transistors (BJTs). A terminal 51 of the transistor Q1 is coupled to a power supply VDD, a terminal 53 of the transistor Q1 is coupled to a node N1, and thus is coupled to one of resistors Rs1 and Rs2 through a switch S1. A control terminal 52 of the transistor Q1 is coupled to a terminal 54 of the transistor Q2. The terminal 54 of the transistor Q2 is coupled to the power supply VDD through a resistor Ra and the switch S2. The transistors Q1-Q2, the resistor Ra, and RS1 supply power as a constant current source, and the transistors Q1-Q2, the resistor Ra, and RS2 supply power as another constant current source. In response to the switch control signal PWM needing to control the wide-bandgap semiconductor transistor 14 to conduct, the switch S2 is turned on, and the terminal 54 of the transistor Q2 is coupled to the power supply VDD through the resistor Ra. The pull-up circuit 21A and the resistor Rs1, or the pull-up circuit 21A and Rs2 pull up the gate 101 of the wide-bandgap semiconductor transistor 14. A control terminal 55 of the transistor Q2 is coupled to the terminal 53 of the transistor Q1, and a terminal 56 of the transistor Q2 is coupled to the node N2 and the resistors Rs1-Rs2. The node N2 is further coupled to an output terminal 15 of the current-type driver 40. The resistors Rs1-Rs2 are coupled between the node N2 and the node N1. In response to the switch control signal PWM needing to control the wide-bandgap semiconductor transistor 14 to turn off, the switch S2 is turned off to disconnect the electrical connection between the terminal 54 of the transistor Q2 and the power supply VDD, so that the pull-up path of the gate 101 of the wide-bandgap semiconductor transistor 14 is turned off. In one embodiment, the terminals 51 and 54 are the collectors of the transistors Q1-Q2 respectively, the terminals 52 and 55 are the bases of the transistors Q1-Q2 respectively, and the terminals 53 and 56 are the emitters of the transistors Q1-Q2 respectively.

[0028] In Figure 4In the illustrated embodiment, the current monitoring circuit 122A includes a comparison circuit 57. The comparison circuit 57 is coupled to node N1 and receives the voltage Vb at the terminal 53 of the transistor Q1 as a current sampling signal to reflect the decrease in the gate current Ig. The comparison circuit 57 provides a current setting signal Iset by comparing the voltage Vb with a threshold Vbth, that is, by comparing the current sampling signal with the threshold. In one embodiment, the comparison circuit 57 includes a comparator. The comparison circuit 57 has a power supply terminal 41 coupled to the power supply VDD and a reference terminal 42 coupled to node N2, such that the voltage reference for the comparison circuit 57 and its two input terminals is node N2. The comparison circuit 57 provides a current setting signal Iset by comparing the voltage Vbe between the terminals 55-56 of the transistor with the threshold Vbth. According to the comparison result of the threshold Vbth and the voltage Vbe, the terminals 53, 55 are selectively coupled to one of the resistors Rs1 and Rs2. In one embodiment, one end of the switch S1 is coupled to node N1, and the other end of the switch S1 is selectively coupled to one of the resistors Rs1 and Rs2 under the control of the current setting signal Iset to set the gate current Ig. By default, the turn-on circuit 12A limits the gate current Ig through the transistors Q1-Q2, the resistors Ra, Rs1, and charges the gate 101 of the wide-bandgap semiconductor transistor 14 at a first constant rate. In this state, the voltage Vbe is the voltage drop when the transistor Q2 is fully turned on. For example, the voltage Vbe is in the range of 0.5V to 0.7V. When the gate 101 of the wide-bandgap semiconductor transistor 14 is fully charged, the gate current Ig decreases and the voltage Vb decreases. The comparison circuit 57 can monitor the decrease in the gate current Ig by monitoring the voltage Vb. When the voltage Vbe drops to the threshold Vbth, the turn-on circuit 12A can provide a lower gate current Ig through the transistors Q1-Q2, the resistors Ra, Rs2. In one embodiment, the threshold Vbth is 0.4V, which is the voltage drop Vbe when the transistor Q2 is fully turned on.

[0029] In Figure 4 In the illustrated embodiment, the turn-off circuit 13A includes a pull-down resistor Rd and a pull-down field-effect transistor 232. The pull-down resistor Rd and the pull-down field-effect transistor 232 are serially coupled between the gate 101 and the reference ground Vss. In one embodiment, the reference ground Vss is coupled to the source 103 of the wide-bandgap semiconductor transistor 14. In one embodiment, when the switch control signal PWM indicates that the wide-bandgap semiconductor transistor 14 needs to be turned off, the pull-down field-effect transistor 232 is turned on through the driver 233, and the gate 101 of the wide-bandgap semiconductor transistor 14 is pulled down to the reference ground Vss through the pull-down resistor Rd and the pull-down field-effect transistor 232. In one embodiment, the pull-down resistor Rd can be the on-resistance of the pull-down field-effect transistor 232.

[0030] Figure 5Shows a schematic diagram of a current - type driver 50 according to an embodiment of the present invention. As Figure 5 shown, the current - type driver 50 is integrated on an integrated circuit (IC). The current - type driver 50 has an input pin 61, output pins 62 - 63, and a power supply pin 64. The input pin 61 receives a switching control signal PWM. The output pins 62 - 63 are coupled to the gate 101 of the wide - bandgap semiconductor transistor 14, and the power supply pin 64 is coupled to the power supply VDD. As Figure 5 shown, the turn - on circuit 12A is coupled to the output pin 62 to pull up the gate 101, and the turn - off circuit 13A is coupled to the output pin 63 to pull down the gate 101. In one embodiment, in response to a first state of the switching control signal PWM, the current - type driver 50 first provides a first constant current to the gate 101 of the wide - bandgap semiconductor transistor 14 through the output pin 62, and then switches to a second constant current to the gate 101 of the wide - bandgap semiconductor transistor 14 through the output pin 62. In one embodiment, in response to a second state of the switching control signal PWM, the gate driver 50 pulls down the gate 101 of the wide - bandgap semiconductor transistor 14 through the output pin 63. In one embodiment, the output pin 52 is coupled to a resistor Rs1 and a resistor Rs2.

[0031] Figure 6 Shows a schematic diagram of a current - type driver 60 according to an embodiment of the present invention. As Figure 6 shown, the current - type driver 60 is integrated on another IC. The current - type driver 60 has an input pin 61, output pins 62, 63, 65, and a power supply pin 64. The output pin 62 is coupled to the gate 101 through a resistor Rs1 to establish a first constant current. The output pin 65 is coupled to the gate 101 through a resistor Rs2 to establish a second constant current. As Figure 6 shown, the turn - on circuit 12B is coupled to the output pins 62 and 65 to pull up the gate 101. Placing the resistors Rs1 and Rs2 outside the IC can better adapt to the gate - driving requirements of different types of transistors.

[0032] Figure 7 Shows a driving method 700 for a wide - bandgap semiconductor transistor according to an embodiment of the present invention. The driving method 700 includes steps S11 - S14.

[0033] In step S11, a switching control signal is received.

[0034] In step S12, in response to a first state (e.g., logic high) of the switching control signal, a first constant current is provided to the gate of the wide - bandgap semiconductor transistor, thereby quickly turning on the wide - bandgap semiconductor transistor.

[0035] In step S13, after the gate of the wide-bandgap semiconductor transistor is fully charged to the maximum voltage, it automatically switches to providing a second constant current to the gate of the wide-bandgap semiconductor transistor to control the wide-bandgap semiconductor transistor to maintain conduction while having a lower gate power consumption. The second constant current is lower than the first constant current. In one embodiment, the first constant current is established through a first resistor, and the second constant current is established through a second resistor.

[0036] In step S14, in response to the second state (e.g., logic low) of the switch control signal, the gate of the wide-bandgap semiconductor transistor is pulled down to turn off the wide-bandgap semiconductor transistor.

[0037] In one embodiment, the driving method 700 further includes establishing a first constant current through a first resistor, and when the current flowing through the gate of the wide-bandgap semiconductor transistor drops below a threshold, establishing a second constant current through a second resistor.

[0038] It should be noted that the execution order of the steps in the above flow chart is not limited to Figure 7 as shown, two consecutive functional blocks can be executed simultaneously or in the reverse order.

[0039] Although the present invention has been described with reference to several exemplary embodiments, it should be understood that the terms used are illustrative and exemplary, rather than restrictive. Since the present invention can be embodied in many forms without departing from the spirit or essence of the invention, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be broadly construed within the spirit and scope defined by the appended claims. Therefore, all changes and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A current-mode driver for a wide bandgap semiconductor transistor, comprising: an input terminal configured to receive a switch control signal; an output terminal coupled to a gate of the wide bandgap semiconductor transistor; an on-circuit coupled to the output terminal, wherein the on-circuit provides a gate current flowing into a gate of the wide bandgap semiconductor transistor through the output terminal in response to a first state of the switch control signal, so as to drive the wide bandgap semiconductor transistor; as well as a shut-down circuit coupled to the output terminal, wherein the shut-down circuit pulls down the gate of the wide bandgap semiconductor transistor and shuts down the wide bandgap semiconductor transistor in response to a second state of the switch control signal; in When the switch control signal changes to a first state, the turn-on circuit first drives the wide bandgap semiconductor transistor with a first constant current, and then drives the wide bandgap semiconductor transistor with a second constant current that is smaller than the first constant current.

2. The current-mode driver according to claim 1, wherein the turn-on circuit sets the first constant current through a first resistor, and sets the second constant current through a second resistor.

3. The current-mode driver according to claim 1 , wherein after the gate voltage of the wide bandgap semiconductor transistor rises to a maximum value, in response to the gate current of the wide bandgap semiconductor transistor falling below a threshold value, the turn-on circuit provides a second constant current to drive the wide bandgap semiconductor transistor.

4. The current mode driver according to claim 1, wherein the turn-on circuit further comprises: a current monitoring circuit configured to monitor the gate current and provide a current setting signal; as well as The current transfer circuit is coupled to a power source, and pulls up the gate of the wide bandgap semiconductor transistor through one of the first constant current and the second constant current according to the current setting signal and the switch control signal.

5. The current mode driver of claim 4, wherein when the switch control signal changes to a first state, the current transfer circuit provides the first constant current, and thereafter in response to the current setting signal, the current transfer circuit provides the second constant current.

6. The current mode driver as claimed in claim 4, wherein the current monitoring circuit further comprises: The comparison circuit receives a current sampling signal and provides the current setting signal by comparing the current sampling signal with a threshold value, wherein the current sampling signal is used to reflect the drop of the gate current.

7. The current mode driver according to claim 1, wherein the turn-on circuit further comprises: a first transistor comprising a collector, an emitter, and a base, wherein the collector of the first transistor is coupled to a power source, the emitter of the first transistor is coupled to a first node, and the base of the first transistor is coupled to the power source via a switch, wherein the switch is turned on and off according to a switch control signal; as well as a second transistor including a collector, an emitter, and a base, wherein the collector of the second transistor is coupled to the base of the first transistor, the emitter of the second transistor is coupled to the second node, and the base of the second transistor is coupled to the emitter of the first transistor; in A first resistor and a second resistor are coupled between the first node and the second node, and the second node is coupled to the output terminal.

8. The current mode driver according to claim 7, wherein the turn-on circuit further comprises: The comparison circuit compares the voltage between the base and the emitter of the second transistor with a threshold value, and selectively couples the emitter of the first transistor and the base of the second transistor to one of the first resistor and the second resistor according to the comparison result.

9. A driving method for a wide bandgap semiconductor transistor, comprising: receiving a switch control signal; In response to a first state of the switch control signal, providing a first constant current to a gate of the wide bandgap semiconductor transistor to turn on the wide bandgap semiconductor transistor; After the gate voltage of the wide bandgap semiconductor transistor rises to a maximum value, automatically switching to provide a second constant current lower than the first constant current to the gate of the wide bandgap semiconductor transistor, so as to control the wide bandgap semiconductor transistor to remain turned on; as well as In response to the second state of the switch control signal, the gate of the wide bandgap semiconductor transistor is pulled down to turn off the wide bandgap semiconductor transistor. 10 . The driving method of claim 9 , wherein the first constant current is established through a first resistor, and the second constant current is established through a second resistor.

11. The driving method according to claim 9, further comprising: Establishing a first constant current through a first resistor; as well as When the current flowing through the gate of the wide bandgap semiconductor transistor drops below a threshold, a second constant current is established through the second resistor.

12. The driving method according to claim 9, further comprising: coupling the collector of the first transistor to a power source, and coupling the base of the first transistor to the power source through a switch; coupling a collector of a second transistor to a base of the first transistor, coupling a base of the second transistor to an emitter of the first transistor, and coupling an emitter of the second transistor to a gate of the wide bandgap semiconductor transistor; as well as The switch is controlled to be turned on and off according to the switch control signal.

13. The driving method according to claim 12, further comprising: comparing a voltage between a base and an emitter of the second transistor with a threshold; as well as Based on a comparison result of a voltage between a base and an emitter of the second transistor and the threshold, the emitter of the first transistor and the base of the second transistor are selectively coupled to one of the first resistor and the second resistor.

14. A current-mode driver, comprising: an input pin configured to receive a switch control signal; A power pin configured to be coupled to a power source; as well as A first output pin and a second output pin, wherein the first output pin and the second output pin are commonly coupled to a gate of a wide bandgap semiconductor transistor; in In response to a first state of the switch control signal, the current-mode driver first provides a first constant current through the second output pin, and then switches to providing a second constant current through the second output pin to drive the wide bandgap semiconductor transistor; as well as In response to a second state of the switch control signal, the current-mode driver pulls down the gate of the wide bandgap semiconductor transistor through the first output pin.

15. The current-mode driver according to claim 14, further comprising: a third output pin coupled to the gate of the wide bandgap semiconductor transistor; in The second output pin may be configured to be coupled to a first resistor to establish the first constant current; as well as The third output pin may be configured to be coupled to a second resistor to establish the second constant current. 16 . The current mode driver of claim 14 , wherein the second output pin is configurable to be coupled to a first resistor and a second resistor, wherein the first resistor is used to establish a first constant current, and the second resistor is used to establish the second constant current.

17. The current mode driver as claimed in claim 14, wherein the second constant current is smaller than the first constant current.

18. The current-mode driver according to claim 14, further comprising: a first transistor comprising a collector, an emitter, and a base, wherein the collector of the first transistor is coupled to the power supply, the emitter of the first transistor is coupled to a first node, and the base of the first transistor is coupled to the power supply via a switch, wherein the switch is turned on and off according to a switch control signal; as well as a second transistor including a collector, an emitter, and a base, wherein the collector of the second transistor is coupled to the base of the first transistor, the emitter of the second transistor is coupled to the second node, and the base of the second transistor is coupled to the emitter of the first transistor; in A first resistor and a second resistor are coupled between the first node and the second node, and the second node is coupled to the second output pin.

19. The current-mode driver according to claim 18, further comprising: The comparison circuit compares the voltage between the base and the emitter of the second transistor with a threshold value, and selectively couples the emitter of the first transistor and the base of the second transistor to one of the first resistor and the second resistor according to the comparison result.

20. The current-mode driver of claim 14, further comprising: an on-circuit, coupled to the second output pin, and in response to a first state of the switch control signal, the on-circuit pulls up the gate of the wide bandgap semiconductor transistor and controls the wide bandgap semiconductor transistor to be turned on; in After the gate current of the wide bandgap semiconductor transistor rises to a maximum value, in response to the gate current of the wide bandgap semiconductor transistor falling below a threshold, the turn-on circuit provides a second constant current to drive the wide bandgap semiconductor transistor.

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