A junction gate transistor with a driving auxiliary circuit

Abstract

The present invention provides a junction gate transistor with a driving auxiliary circuit. The present invention introduces a driving auxiliary circuit into the gate, wherein the driving auxiliary circuit includes a variable impedance network and a control network. This allows the variable impedance network to maintain low impedance due to the effect of the control network during the transient change of the input voltage, and to become high impedance and limit the gate current when the input is in a steady state, thereby reducing device losses and improving the switching efficiency of the system. In addition, this driving auxiliary circuit makes the gate turn-on delay very short. In addition, due to the voltage-dividing effect of the variable impedance network, the applied voltage value is greatly increased, which can be compatible with the voltage equalization of the traditional Si device driving circuit, and overcome the disadvantage of excessive gate power consumption of the new generation of semiconductor devices.

Description

Technical Field

[0001] The invention belongs to the field of power semiconductors, and in particular relates to a junction gate transistor with a driving auxiliary circuit. Background Art

[0002] With the vigorous development of new energy and the widespread application of power electronics, ordinary Si-based devices cannot meet the application requirements in high-voltage, high-temperature and high-frequency environments. The third-generation semiconductors such as SiC and GaN materials have excellent characteristics such as large bandgap, high breakdown voltage and high thermal conductivity, which provide possibilities for the new generation of power electronic devices and systems. However, due to the inherent characteristics of the third-generation semiconductor power devices, the existing drivers for Si materials are not suitable for the application of third-generation semiconductor devices, especially SiCJFET and GaN HEMT. This is mainly manifested in the following aspects: on the one hand, the gate can withstand a small voltage, generally not exceeding 5V, while the existing driver input voltage is generally more than 10V; on the other hand, its gate current is large when the device is working in steady state, which increases the gate power consumption and driver power consumption, which not only brings device reliability problems, but also reduces the efficiency of the entire power system and increases the difficulty of isolation design of the drive circuit.

[0003] There are two main methods for reducing gate current in the literature: large series resistor and AC coupling circuit. Although these auxiliary drive circuits can reduce the gate current in steady state, they still introduce other problems. Figure 2 The large resistor in series as shown has a large gate delay, slow switching speed and high loss. Figure 3 The AC coupling circuit shown still has a high gate delay, a complex drive circuit design, and a large capacitor that is difficult to integrate. Summary of the invention

[0004] In view of the defects of the prior art, the present invention provides a junction gate transistor with a driving auxiliary circuit. The present invention introduces a driving auxiliary circuit Q at the gate, wherein the driving auxiliary circuit Q includes a variable impedance network Z and a control network C. This allows the variable impedance network Z to maintain a low impedance due to the effect of the control network C during the transient change of the input voltage, and to become a high impedance and limit the gate current when the input is in a steady state, thereby reducing device losses and improving the switching efficiency of the system, and this driving auxiliary circuit makes the gate turn-on delay very short. In addition, due to the voltage-dividing effect of the variable impedance network Z, the external voltage value is greatly increased, which can be compatible with the output voltage equipolarity driven by traditional Si materials, and overcome the disadvantage that the gate of the third-generation semiconductor device is easy to break down.

[0005] The technical solution to achieve the purpose of the present invention is: a junction-gate transistor with a driving auxiliary circuit, comprising: a junction-gate transistor T and a driving auxiliary circuit Q, wherein the driving auxiliary circuit Q comprises a variable impedance network Z and a control network C; when the driving input is a steady-state first potential, the variable impedance network Z is low impedance, when the driving input suddenly changes to a second potential, the control network C can adjust the variable impedance network Z to high impedance after a short delay, and when the driving input enters the second potential steady state, the control network C keeps the variable impedance network Z at high impedance.

[0006] Wherein, the gate of the junction-gate transistor T is at least one of a PN junction, a Schott junction and a heterojunction.

[0007] Wherein, the body material of the junction gate transistor T is Si, Ge, SiC, GaN, Al x Ga 1-x At least one of N, AlN, InP, diamond and Ga2O3.

[0008] Wherein, the low impedance value of the variable resistor network Z is less than 50 ohms, and the high impedance value thereof is greater than twice the low impedance value.

[0009] Wherein, when the driving input is at the first potential, the junction-gate transistor T is turned off, and when the driving input is at the second potential, the junction-gate transistor T is turned on.

[0010] Wherein, the first potential is a low potential, and the second potential is a high potential.

[0011] Wherein, the first potential is a high potential, and the second potential is a low potential.

[0012] The short delay causes the impedance of the variable resistance network Z to change after the junction-gate transistor T is fully turned on.

[0013] Among them, the driving auxiliary circuit Q can be an integrated circuit integrated in the same chip as the junction gate transistor T, an independent integrated circuit chip placed in the same package, integrated on the same chip with the driving chip, or a discrete device assembled in the circuit system.

[0014] Wherein, the variable impedance network Z is composed of at least one of a transistor, a resistor and a capacitor.

[0015] Wherein, the control network C is at least one of an RC network, a cascade inverter and a Schmitt trigger. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The invention discloses a junction gate transistor with a driving auxiliary circuit.

[0017] Figure 2 It is a traditional drive auxiliary circuit with large resistance.

[0018] Figure 3 It is a traditional driver auxiliary circuit with AC coupling circuit.

[0019] Figure 4 This is an integrated driving circuit diagram based on Si-based enhancement mode 650VGaN HEMT provided in the first specific embodiment of the present invention.

[0020] Figure 5 It is the simulation waveform diagram in Example 1. One is the gate current waveform diagram after adding a large resistor, and the input signal is a square wave of 0~10V; the other is the gate current waveform diagram after adding the driver of the present invention, and the input signal is a square wave of 0~10V. DETAILED DESCRIPTION

[0021] In order to make the purpose and advantages of the technical solution of the present invention more clearly understood, the present invention is further described in detail below in combination with embodiments and with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] like Figure 4 The circuit diagram of the first embodiment is shown, and the circuit includes a junction gate transistor T1, a variable impedance network Z1 and a control network C1. The variable impedance network Z1 is composed of a current limiting resistor R lim and a control switch T2; and a control network C1 is composed of a capacitor C and a resistor R. In this embodiment, all components are integrated in the same substrate.

[0023] In the first embodiment of the present invention, the bulk material is gallium nitride material.

[0024] In the first embodiment of the present invention, the junction gate transistor T1 and the control switch T2 are both enhanced P-type gate GaNHEMT (High Electron Mobility Transistor). For the main switch device, its threshold voltage is 1.2V and its forward blocking voltage is 650V.

[0025] In the first embodiment of the present invention, the control switch T2 is a symmetrical device, and is manufactured using the same process as the junction-gate transistor T1.

[0026] In the first embodiment of the present invention, the resistor R may be manufactured using a two-dimensional electron gas block resistor and the capacitor C may be manufactured using a gate capacitor.

[0027] The working principle of this example is:

[0028] When the input signal jumps from low level to high level, C is charged first, and the control switch is turned on briefly to provide a large gate drive current; when the high level reaches a steady state, the control switch is turned off because the voltage difference of the control switch is reduced to less than its threshold voltage, and the current flows through a large current limiting resistor R lim , controlling the gate current, thus reducing gate loss. When the input signal jumps from high level to low level, the capacitor C discharges through the resistor R, and the device is turned off.

[0029] In the second embodiment of the present invention, the junction gate transistor T and the auxiliary driving circuit Q are integrated and packaged in two chips respectively.

[0030] In the third embodiment of the present invention, the junction gate transistor T is packaged in a chip, and the auxiliary driving circuit Q is soldered in the PCB circuit board in the form of a separate device.

Claims

1. A junction gate transistor with a driving auxiliary circuit, characterized in that: include: A junction gate transistor (T) and a driving auxiliary circuit (Q), wherein the driving auxiliary circuit (Q) includes a variable impedance network (Z) and a control network (C); When the driving input is at a steady-state first potential, the variable impedance network (Z) is at a low impedance. When the driving input suddenly changes to a second potential, the control network (C) can adjust the variable impedance network (Z) to a high impedance after a short delay. When the driving input enters the second potential steady state, the control network (C) keeps the variable impedance network (Z) at a high impedance. The control network (C) is briefly delayed so that the impedance of the variable resistance network (Z) changes after the junction gate transistor (T) is fully turned on; The control network (C) is at least one of a capacitor-resistor network, a cascade inverter and a Schmitt trigger; The driving auxiliary circuit (Q) is an integrated circuit integrated in the same chip as the junction gate transistor (T), an independent integrated circuit chip placed in the same package, integrated on the same chip as the driving chip, or a discrete device assembled in the circuit system.

2. A junction gate transistor with a driving auxiliary circuit according to claim 1, characterized in that: The gate of the junction-gate transistor (T) is at least one of a PN junction, a Schott junction and a heterojunction.

3. A junction gate transistor with a driving auxiliary circuit according to claim 1, characterized in that: The low impedance value of the variable impedance network (Z) is less than 50 ohms, and the high impedance value is greater than twice the low impedance value.

4. A junction gate transistor with a driving auxiliary circuit according to claim 1, characterized in that: When the driving input is at a first potential, the junction-gate transistor (T) is turned off, and when the driving input is at a second potential, the junction-gate transistor (T) is turned on.

5. The junction gate transistor with a driving auxiliary circuit according to claim 1, characterized in that: The variable impedance network (Z) is composed of at least one of a transistor, a resistor and a capacitor.

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