Igbt help?

Good night, how are you? I’m using the igbt gt50jr22 in my projects, I wanted to know which is the best switching frequency for me to use and the best gate resistor using a gate voltage of 15v? and a voltage of 400v between drain and source


Unfortunately there’s no clear answer to either of your questions; switching frequencies will be limited at the high end by the device’s switching characteristics and likely to a figure in the 10s of kHz, but below that point it’s a question of making a choice and living with the resulting tradeoffs.

Similarly, choice of a gate resistance (if any) is based on other considerations. One usually wants enough to prevent ringing of the L-C circuit formed by the gate capacitance with parasitic inductance in the drive circuit, but more leads to slower switching and (usually) increased losses.

Manufacturers’ application notes are a good resource for gaining more insight into these sorts of questions. This one and this one are examples of the kind. The datasheets themselves are also useful; they don’t usually contain a lot of useless information, so if there’s something in a datasheet you don’t understand, view that as a pointer to something that you probably want to learn about.

Also, that’s not a children’s transistor you’re talking about, and the sort of circuits it’s suited for are not forgiving. Please use utmost caution when dealing with such things.

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Hello daviqueirozbarroso,

Constructing power electronics can be a challenge. Yet, it is a worthy goal as there are many lessons to be learned.

While I don’t have a direct answer to your question I can give you some pointers. For example, are you familiar with dedicated gate drive ICs such as those listed here:

You may be able to find some good ideas in the associated datasheets or application notes such as https://www.digikey.com/en/products/detail/infineon-technologies/IR2213PBF/1928077 and https://www.farnell.com/datasheets/2254418.pdf

rick_1976 is correct. This is no toy you are building. Mistakes typically result in a ball of fire that destroys the output IGBT(s), the driver IC, the associated microcontroller, and if you are, unlucky the attached PC. Yes, I’m speaking from experience. Also, don’t underestimate the danger associated with a 400 VDC system. It will kill you or someone you love if you make a mistake.

May I recommend you start small with a circuit to control the speed and direction of a 24 VDC brush-type motor. This will allow you to gain experience and build confidence without the expense and frustration of the fireball. Once you have the motor operating you can explore parameters such as gate resistance, bootstrapping, PWM frequency, and snubber circuits. As a general rule, the lessons learned at low voltage scale to the higher voltage systems.

Best Wishes,


P.S. Don’t become complacent with the low voltage experiments as bad habits will be deadly when the voltage is increase.

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IGBTs in power switching applications require a negative gate voltage to be applied to turn them off. Zero volts is not enough.
There used to be an excellent International Rectifier app note. But when Infineon acquired IR, all of the IR’s app notes got merged with Infineon’s, which is not very search-friendly. But I would advise you to take your time to search for them, as they provide invaluable information, and much more detail than what you could get in an open forum.