Hi guys !

I'm working on my drsstc and after many researches on how to drive an igbt, i want to share with you a new design of the IGBT gate drive circuit. This circuit can be use to drive efficiently one or more IGBT in parallel.

Motivation :
New technologies of IGBT are more suitable for paralleling operations. When you want to build small to medium power SSTC, you can choose between IGBT module or TO247. As TO247 are cheaper, it could be a better choice to use two or more TO247 in parallel than using an IGBT module, especially if you want to drive them at high frequency.


Since I design DRSSTC, the most efficient gate driver circuit I saw is the circuit with a diode to shunt the gate resistance. The aim of the diode is to reduce the gate resistance when discharging the gate to turn off quickly the IGBT. But the reduction of this resistance increase the voltage on the gate because the RLC circuit of the driver is under-damped.


To solve this problem, instead of using a diode, you can use a PNP transistor close to the gate to short it. The discharge current will no longer go through the GDT and the current path will have a smaller loop which means a smaller parasitic inductance. You can find more information on the TI application report "Fundamentals of MOSFET and IGBT Gate Driver Circuits".


The other improvement is the current balancing in parallel operation. When paralleling IGBT, some stray inductance is present at the emitter of the IGBT modules. The value of stray inductance for
the two IGBTs could differ. Because the IGBTs are connected in parallel, the common ground voltage will remain the same for both the IGBTs but the auxiliary emitter voltages will differ. This voltage difference between the auxiliary emitter terminals of the two IGBTs results in current flow from one terminal to the other. Depending on the direction of the circulating current the actual voltage at the IGBT gates will either increase or decrease resulting in unequal current sharing.
To overcome this problem, you can use a emitter resistor to help attenuating the circulating current or/and use a common-mode choke in the gate path.

This lead me to design this gate driver circuit.

It requires only 3 additional components to improve the driving. and if you just want to use it to drive one transistor, you can simply solder jumper instead of the common mode choke.


To finish the design of this driver, i still need to find a reference for the D1, Q2 and L1.

Tell me what do you think about this circuit and if you have any comments

If you are curious you can find more information on this paper :
- TI Designs "IGBT Gate Driver Reference Design for Parallel IGBTs With Short-Circuit Protection and External BJT Buffer" TIDUC70A
- TI Application Report "Fundamentals of MOSFET and IGBT Gate Driver Circuits" SLUA618A

Great Job, I really liked the article !

The coil was design to represent my engineering school during events, we want to make long spark and play music so I think the tuning will change depending where I present it ( I don't think I'm allowed to make 3m spark in a classroom  ). I order IGBT on rs-online, they was paid by my school with the DC bus caps but recently I saw on semikron website that you can order samples IGBT brick. I didn't tried yet.

For my 200mm secondary, I used wooden disc at the ends and 4 3d printed disc of PLA in the tube

Thank you Mads for your answer 

I think the best way is to test both 438nF and 500nF. Futhermore, it will reduce the maximum number of turns of my primary and the price ahah

Hello coilers,

Last week I finished my DRSSTC and the first test gave me 240cm of spark. My goal is 3m and I have many tracks of improvement. I wondering how can I choose the Primary Impedance for a given frequency and the impact of it.

I use GTO capacitors rated at 3,5uF 1500Vdc per caps.

With my primary coil, I can change my primary caps for 388nF (9 GTO in series), 435nF (8 GTO in series) or 500nF (7 GTO in series) to stay between [52-60]kHz depending how much I want to detune my coil. I've done some simulation with different L C and Fres values to calcultate Z surge, it's between 5,64 and 7 depending F res chosen.



Ocd is set at 1350 but I can push it at 1700A easily with SKM400GB125D IGBT.

Based on your experience wich primary capacitance is the best to perform the biggest streamer ?

Hi everyone,

My name is Alexandre, i'm a french student in Electrical Engineering. I began to build tesla coil last year with a first SGTC then i upgrade it in DRSSTC mode. I have geat projects with tesla coil, my school (INSA LYON) ask me to promote it in differents science events near Lyon

To build a good MMC, you can use 942C capacitor serie from Cornell Dublier or C4AS serie from Kemet. For my DRSSTC I use C4AS 680nF 1200V capacitor, they have a better Irms in 4 pins configuration than 942C.

Hello Everybody i'm proud to introduce you my first DRSSTC built for an engineer project school !

Last year I decided to built a large SGTC but the price of my 942C MMC was to high for my budget and I don't have a 220V/32A power source. So I decided to change the technology of my Tesla in order to supply it with a 3phase power source.
(video of my SGTC last year)


I use the plan of F. Franzoli for his DRSSTC III for the full bridge, driver, PSU and interrupter. I saw that his OCD is at 1200A. Due to the low impedance of my primary I think it will reach 1000A peak. I need to find an IGBT module wich can handle this curent at the resonant frequency of my secondary.

I made a simulation on JavaTC3D. I saw that the surge impedance of the secondary need to be close to 50kOhm. I have two size of wire : 0.4 and 0.475mm. With my actual secondary and size of the coil (200*1080mm) I can reach a couple of values for frequency and surge impedance :

Size of wire | Number of turns | Frequency |  Z surge
0.475            1850                    63.41 kHz   52 kOhm
0.475            2000                    60.95 kHz   54.6 kOhm
0.4                2100                    52.6 kHz    61.6 kOhm
0.4                2400                    49.8 kHz    66.5kOhm

My first question is witch case I should take ? I prefer the first for the low impedance but I'm affraid that at 63kHz it would be hard to find an IGBT module for 1000Apeak.

So the second question is which module I should use ? I saw CM300DY-24NFH and SKM400GB125D. I think the SKM is really good for my DRSSTC but it is more expensive. Do you have seen an other model for a DRSSTC at this frequency and this peak current ?


Thanks you for your help. I have one month to finish the circuit ^^. I will post more information about this project.

PS : i'm sorry, it's my first time on a forum, i don't know how to post pictures of my tesla... :/