3rd world problems
Doge123, Mon Apr 10 2017, 10:00PMHi guys! I am from a country called Nepal. I have always wanted to build a singing Tesla coil and I have recently started collecting parts. I based my design around the OneTeslaTS DRSSTC whose schematics and tutorials were easily available online. It is quite hard to source parts in this part of the world which is ironic since China is our next door neighbors. Anyways, some kind gentleman online sent me some gate driver ICs UCC37321 for free. Thanks again random stranger. Now, I have run into a problem. Only IGBTs available in our country is bootleg FGA25N120 (it is widely used in induction cookers and heaters) which has quite slow turn off delay time of 170ns at 25C. I don't know if I can get anything usable out of it. What is the general rule for IGBTS. How fast do they need to be for a given frequency?
Re: 3rd world problems
Conundrum, Wed Apr 12 2017, 11:32AM
Can you compensate for this by using resistors?
IIRC IGBTs are a hybrid of a BJT and a MOSFET (Insulated Gate) so they in common with MOSFETs have a significant gate capacitance.
Conundrum, Wed Apr 12 2017, 11:32AM
Can you compensate for this by using resistors?
IIRC IGBTs are a hybrid of a BJT and a MOSFET (Insulated Gate) so they in common with MOSFETs have a significant gate capacitance.
Re: 3rd world problems
Bjørn, Wed Apr 12 2017, 03:59PM
If we make a guess and say it should be fully on for about 90% of the time.
frequency = 1 / ((turn on time + turn off time) * 10)
= 294 kHz (If turn on is as slow as turn off)
How well it will work for your application depends on how good your heatsinking is and what you would consider to be a good result.
Bjørn, Wed Apr 12 2017, 03:59PM
If we make a guess and say it should be fully on for about 90% of the time.
frequency = 1 / ((turn on time + turn off time) * 10)
= 294 kHz (If turn on is as slow as turn off)
How well it will work for your application depends on how good your heatsinking is and what you would consider to be a good result.
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