JPH0548584U - Gate drive circuit for high-speed switching devices - Google Patents

Abstract

(57) [Abstract] [Purpose] To enable gate driving of multiple parallel high-speed switching elements without impairing miniaturization of the gate drive circuit of the high-speed switching element, and to improve reliability of noise resistance. [Structure] A hybrid IC 1 for an IGBT drive circuit to which a control signal is input is connected to a filter circuit 2 for removing noise in the output signal, and a high speed switching element IG is connected.
An FE in which FET11 and FET12 circuits for driving the gate of BT are connected in series between the positive and negative power supplies, and the filter circuit 2 operates at a predetermined switching threshold value for its output signal.
The gate signal generation circuits 3 ₁ and 3 ₂ of T11 and FET 12 are connected, and the FET 11 and FET are driven by this gate signal.
The 12 gate circuits are connected with turn-off speed-up circuits 4 ₁ and 4 ₂ for rapidly removing the charge accumulated in the gate input capacitance when the gate signal of each FET is turned off.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a gate drive circuit for a high-speed switching element in a forward conversion unit / inverse conversion unit of a power conversion device.

[0002]

[Prior Art]

 In recent years, power converters such as general-purpose inverters and uninterruptible power supplies have been miniaturized, and there has been a demand for miniaturization of drive circuits for high-speed switching devices such as IGBT devices inside the devices. As a means for miniaturizing the drive circuit, there is a hybrid IC part of the circuit.

FIG. 2 shows an IGBT gate drive circuit using a hybrid IC (hereinafter referred to as HIC) for an IGBT drive circuit, which has been commercialized now and is expected to be widely used in the future. In FIG. 2, HIC1 comprises a photocoupler 1 ₁ to which an input signal V _IN is input via a resistor R _D, and a transistor circuit 1 _{2 which is} switched by the output signal of this photocoupler 1 ₁ , and the IGBT is connected via a gate resistor R _G. Driven by the output V _OUT of the HIC1.

[0004]

[Problems to be solved by the device]

 Since the conventional HIC drives the gate of the IGBT with its output, the following problems occur.

(1) A current exceeding the rated value cannot flow in the transistor inside the HIC. Therefore, when trying to drive the multi-parallel circuit of the IGBT, the HIC is overloaded and cannot be used.

(2) Since the input signal is input to the transistor circuit via the photocoupler, when a noise current flows in the input signal, the output of the HIC malfunctions due to noise, and there is a risk of destroying the IGBT.

The present invention has been made in view of the above problems of the related art, and an object thereof is to provide a gate drive of a multi-parallel high-speed switching element without impairing miniaturization of the gate drive circuit. It is possible to provide a gate drive circuit for a high-speed switching element that enables high reliability and is resistant to noise.

[0008]

[Means for Solving the Problems]

 In order to achieve the above object, a gate drive circuit of a high speed switching device according to the present invention comprises a hybrid IC for an IGBT drive circuit to which a control signal is input, a filter circuit for removing noise in an output signal of the hybrid IC, and a high speed First and second FET circuits connected in series between the positive and negative power supplies that drive the gate of the switching element, and the first and second FET circuits that operate at a predetermined switching threshold for the voltage value of the output signal of the filter circuit. And first and second gate signal generation circuits for generating gate signals for the second and second FETs, and gate signals for the respective FETs connected to the gate circuits for the first and second FETs driven by this gate signal Turn-off speed-up circuit that rapidly removes the charge accumulated in its gate input capacitance at the turn-off time. That.

[0009]

[Action]

 The input signal is amplified by the hybrid IC and the noise contained in the output signal is removed by the filter circuit. The first and second FET gate signal generation circuits operate at a predetermined switching threshold with respect to the voltage value of the output signal of the filter circuit and generate a FET gate signal with dead time.

Since the first and second FETs drive the high speed switching element base by the FET gate signal, the high speed switching element does not malfunction due to noise. The first and second turn-off speed-up circuits speed up the first and second FETs that drive the gates of the high-speed switching elements by rapidly removing the charge accumulated in each gate input capacitance when the gate signal of each FET is turned off. Turn off with.

[0011]

【Example】

 An embodiment of the present invention will be described with reference to FIG.

In FIG. 1, 1 is a hybrid IC (HIC) for an IGBT drive circuit, 2 is a filter circuit composed of a resistor R ₁ and a capacitor C ₁ for removing a noise malfunction signal of an output V _OUT of the HIC ₁ .

Reference numerals 3 ₁ and 3 ₂ denote base signal generation circuits for the output stage p-channel FET 11 and n-channel FET 12 that drive the IGBT 13. The output of the filter circuit 2 is input to the base via a resistor R ₂ and a zener diode ZD _1. transistor Tr ₁ circuit及beauty resistor R ₃ to, a transistor T r ₂ circuit for input to the base via a Zener diode ZD _2.

The Zener diodes ZD ₁ and ZD _{2 change} the switching thresholds of the transistors Tr ₁ and Tr ₂ with respect to the output voltage of the filter circuit 2 by V _ZD1 + V _{BE (TR1)} and − (V _ZD2 + V _{BE (TR2), respectively.} ), And a dead time section for preventing an arm short circuit phenomenon in which the output stage FET11 and FET12 are simultaneously turned on in the section where the output voltage of the filter circuit 2 exceeds this threshold voltage. It is made to switch the transistors Tr ₁ and Tr ₂ .

The gates of the FET 11 and the FET 12 are transistors Tr₁And Tr₂Collector resistance R_FourAnd R_FiveIn parallel with diode D₁And D₂Series resistor R connected via ₆ , R₇And R₉, R_TenWhen the FET11 is on and the FET12 is off, the gate / emitter voltage of the IGBT13 is + 15V and the IGBT is on. When the FET11 is off and the FET12 is on, the gate / emitter voltage of the IGBT13 is -15V and the IGBT is Turn off.

Reference numerals 4 ₁ and 4 ₂ are provided in the gate circuits of the FET 11 and FET 12, and are turn-off speed-up circuits for quickly removing the charges accumulated in the gate capacitance (C iss) of each FET when the gate signals of the FET 11 and FET 12 are turned off. The bases of the transistors Tr ₃ and Tr ₄ are connected to the collectors of the transistors Tr ₁ and Tr ₂ via the diodes D ₃ and D ₄ , and the emitters thereof are connected to the gates of the FET 11 and FET 12, respectively. .

With the above configuration, the output voltage V _{OUT of the} HIC ₁ is noise-removed by the filter 2, and the transistors Tr ₁ and Tr ₂ are noise-removed output voltage V _OUT and the Zener diode ZD ₁ And ZD ₂ controls the dead time. Further, since the FET 11 and the FET 12 are turned off at a high speed by the turn-off speed-up circuit, the IGBT 13 operates at a high speed without being affected by noise.

Although the embodiment has been described as an IGBT gate drive circuit, it goes without saying that the same can be applied to a gate drive circuit for a high speed switching element such as a power MOSFET using an HIC.

[0019]

[Effect of the device]

 Since the present invention is configured as described above, it has the following effects.

(1) Since p-channel FETs and n-channel FETs are used in the final stage of gate drive, even when a required number of IGBTs are connected in parallel, they can be driven by appropriately selecting these FETs.

(2) Since the noise malfunction signal generated in the output of the HIC can be removed by the RC filter circuit, the drive circuit becomes highly resistant to noise.

(3) Since all the circuit components added after the HIC can be made compact, the advantage of circuit miniaturization by using the HIC is not impaired.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing an IGBT gate drive circuit according to an embodiment.

FIG. 2 is a block circuit diagram showing a conventional IGBT gate drive circuit.

[Explanation of symbols]

1 ... Hybrid IC (HIC), 2 ... Filter circuit,
3 _1, 3 ₂ ... base signal generating circuit, 4 _1, 4 ₂ ... off speed circuit, 11, 12 ... FET, 13 ... IGBT.

Claims (1)

[Scope of utility model registration request] 1. A hybrid IC for an IGBT drive circuit to which a control signal is input, a filter circuit for removing noise in an output signal of the hybrid IC, and a positive / negative power source for driving a gate of a high speed switching element, which are connected in series. First and second FET circuits, and first and second first gate circuits for operating the first and second FET circuits by operating at a predetermined switching threshold with respect to the voltage value of the output signal of the filter circuit. Gate signal generating circuit, and the first and second FETs driven by the gate signal
A gate drive circuit for a high-speed switching device, comprising: a turn-off speed-up circuit that is connected to the gate circuit of FIG. 1 to rapidly remove the charge accumulated in the gate input capacitance when the gate signal of each FET is turned off.