A circuit for reducing short-circuit protection threshold voltage of silicon carbide modules

Abstract

The utility model discloses a kind of circuit for reducing silicon carbide module one class short-circuit protection threshold voltage, it includes gate isolation driving chip U6, stabilivolt D53, diode D51 and resistance R67, the cathode of diode D51 is connected in the DESAT foot of the gate isolation driving chip U6, the anode of diode D51 is grounded, the anode of stabilivolt D53 is used to connect sampling branch, the resistance R67 is connected between the cathode of stabilivolt D53 and the DESAT foot of the gate isolation driving chip U6. Compared with prior art, the utility model can effectively reduce silicon carbide module one class short-circuit protection threshold voltage, and can be adjusted to reduce desaturation detection threshold voltage according to need, to improve voltage protection effect.

Description

Technical Field

[0001] This utility model relates to threshold protection circuits, and more particularly to a circuit for reducing the short-circuit protection threshold voltage of a silicon carbide module. Background Technology

[0002] Gate isolation driver chips can prevent power devices from being damaged by overload or short circuit, thereby extending the service life of the equipment. In the existing technology, the desaturation detection (DEAT) threshold voltage of various gate isolation driver chips on the market is greater than or equal to 9V. However, silicon carbide chips have a small area and can withstand low heat. Under the maximum operating current, VDS is usually less than 3V. Therefore, in practical applications, a threshold voltage of 5-6V is sufficient. A threshold voltage of 9V is obviously too high, and the protection effect is not obvious. Utility Model Content

[0003] The technical problem to be solved by this invention is to provide a circuit that can adjust the desaturation detection threshold voltage as needed to improve the voltage protection effect, in order to address the shortcomings of the existing technology.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution.

[0005] A circuit for reducing the short-circuit protection threshold voltage of a silicon carbide module includes a gate isolation driver chip U6, a Zener diode D53, a diode D51, and a resistor R67. The cathode of the diode D51 is connected to the DESAT pin of the gate isolation driver chip U6, and the anode of the diode D51 is grounded. The anode of the Zener diode D53 is used to connect to the sampling branch. The resistor R67 is connected between the cathode of the Zener diode D53 and the DESAT pin of the gate isolation driver chip U6.

[0006] Preferably, the circuit includes diodes D55 and D56 connected in series, with the anode of diode D55 connected to the anode of the Zener diode D53, and the cathode of diode D56 used to connect to the sampling branch.

[0007] Preferably, the diode D51 is connected in parallel with a capacitor C147.

[0008] Preferably, the resistance of the resistor R67 is 1KΩ.

[0009] Preferably, the gate isolation driver chip U6 is a chip with the model number UCC21750.

[0010] In this invention, pin 2 (i.e., the DESAT pin) of the gate isolation driver chip U6 is used as a desaturation detection pin. A Zener diode D53 is added to its sampling branch. Specifically, according to the required VDS protection threshold voltage, Zener diodes with different voltage values ​​can be selected, thereby realizing the function of freely adjusting the VDS protection threshold voltage. Compared with the prior art, this invention can effectively reduce the short-circuit protection threshold voltage of silicon carbide modules and can lower the desaturation detection threshold voltage as needed, thereby improving the voltage protection effect. Attached Figure Description

[0011] Figure 1 This is the circuit schematic diagram of this utility model;

[0012] Figure 2 This is a schematic diagram of the internal circuitry of a gate-isolated driver chip. Detailed Implementation

[0013] The present invention will now be described in more detail with reference to the accompanying drawings and embodiments.

[0014] This utility model discloses a circuit for reducing the short-circuit protection threshold voltage of a silicon carbide module. Please refer to [link to relevant documentation]. Figure 1 It includes a gate isolation driver chip U6, a Zener diode D53, a diode D51, and a resistor R67. The cathode of the diode D51 is connected to the DESAT pin of the gate isolation driver chip U6, and the anode of the diode D51 is grounded. The anode of the Zener diode D53 is used to connect to the sampling branch. The resistor R67 is connected between the cathode of the Zener diode D53 and the DESAT pin of the gate isolation driver chip U6.

[0015] In the above circuit, pin 2 (i.e., the DESAT pin) of the gate isolation driver chip U6 is used as the desaturation detection pin. A Zener diode D53 is added to its sampling branch. Specifically, according to the required VDS protection threshold voltage, Zener diodes with different voltage values ​​can be selected to achieve the function of freely adjusting the VDS protection threshold voltage. Compared with the prior art, this utility model can effectively reduce the short-circuit protection threshold voltage of silicon carbide modules and can lower the desaturation detection threshold voltage as needed, thereby improving the voltage protection effect.

[0016] Furthermore, this embodiment includes diodes D55 and D56 connected in series. The anode of diode D55 is connected to the anode of the Zener diode D53, and the cathode of diode D56 is used to connect to the sampling branch. Diodes D51, D55, and D56 provide a path for reverse voltage, preventing adverse effects on the gate isolation driver chip U6.

[0017] As a preferred embodiment, the diode D51 is connected in parallel with a capacitor C147. Furthermore, the resistor R67 has a resistance of 1 kΩ.

[0018] In this embodiment, the gate isolation driver chip U6 is a UCC21750 chip. The desaturation detection pin (pin 2) of this UCC21750 chip is the DESAT pin. The internal workings of the chip are as follows... Figure 2 As shown, when the DESAT pin level reaches 9V, the chip activates its protection function. Excluding the voltage drop of approximately 1V from resistor R and diode DHV, the power transistor voltage drop is approximately 8V, at which point DESAT activates its protection. For silicon carbide chips, this VDS protection threshold voltage is too high, posing a significant risk of failure. To address this, this embodiment adds a Zener diode D53 to the sampling branch. Depending on the required VDS protection threshold voltage, different Zener diode values ​​can be flexibly selected, thereby achieving the function of freely adjusting the VDS protection threshold voltage and better meeting application requirements.

[0019] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. All modifications, equivalent substitutions or improvements made within the technical scope of the present utility model should be included within the scope of protection of the present utility model.

Claims

1. A circuit for reducing the short-circuit protection threshold voltage of a silicon carbide module, characterized in that, The device includes a gate isolation driver chip U6, a Zener diode D53, a diode D51, and a resistor R67. The cathode of the diode D51 is connected to the DESAT pin of the gate isolation driver chip U6, and the anode of the diode D51 is grounded. The anode of the Zener diode D53 is used to connect to the sampling branch. The resistor R67 is connected between the cathode of the Zener diode D53 and the DESAT pin of the gate isolation driver chip U6.

2. The circuit for reducing the threshold voltage of a type I short-circuit protection in a silicon carbide module as described in claim 1, characterized in that, It includes diodes D55 and D56 connected in series. The anode of diode D55 is connected to the anode of the Zener diode D53, and the cathode of diode D56 is used to connect to the sampling branch.

3. The circuit for reducing the threshold voltage of a type I short-circuit protection in a silicon carbide module as described in claim 1, characterized in that, The diode D51 is connected in parallel with a capacitor C147.

4. The circuit for reducing the threshold voltage of a type I short-circuit protection in a silicon carbide module as described in claim 1, characterized in that, The resistance of resistor R67 is 1KΩ.

5. The circuit for reducing the threshold voltage of a type I short-circuit protection in a silicon carbide module as described in claim 1, characterized in that, The gate isolation driver chip U6 is a chip with the model number UCC21750.

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