My own SSTC Driver v1.0

[FilipŠebík]

Hey, I just designed my own SSTC driver. Its driver without a mosfet gate driver ICs, because they are expenisve, 3.86 for UCC37321 and 4.34 for UCC37322 and the mosfet stage is 2.76 for the 3 mosfets. Price is in euro of course

Here is the scheme:


There are no 7805 or 7812 regulators in the scheme, because everybody knows that they have to have them to make the 5 and 12 volts, but they don't if they have their own 5 and 12 volt supplies.

If you want the scheme for eagle, then send me a message.

This could drive a big load and be stable, but I need to test it before I can say that it works.

The only thing that I don't know, if the mosfets need any gate resistor at Q3, Q4, Q5 and Q6. If anyone thinks that it might not work because of something, then tell me and I will try to fix it. Thanks

[Zbig]

There are some mistakes and not very good implemented parts in your driver.

1. There is no resistor on drain of Q1 and Q2 - now they are simply shortcuts 12V to ground.
2.  Connecting and driving together  gates of Q4/Q6 (and Q3/Q5) is bad idea. During switching time both MOSFETS will conduct simulaneously which may result in excessive power consumption/heating.
3. There is no overcurrent/time limit for gate open, which may result with MOSFET burn during startup, when feedback is weak.
4. Driving IRFP540 directly form 74HC02 is very bad idea. It has only 5V output with 20mA current, It will result with very slow and weak gate drive. 

You need to read more about MOSFET transistors, and then rethink your design...

[Laci]

Some drivers uses BJT output stages to drive the mosfets,or even the GDT,like this:
https://www.mikrocontroller.net/attachment/284427/U3RBsZAI.png

However I tried this,but it never worked for me.The 5V PWM signal of the level shifter IC was not able to drive the BJTs.The only way I could get this type of driver to drive the transistors was by adding another BJT amplifier to the bases,but that shifted the PWM,so not working.Maybe by using an amplifier IC or a 12V level shifter can do the job,but it's much easier to use mosfet driver IC.You can get 10pcs TC4420 for around 2$ from china,which can easily drive the gate of the mosfets,or the GDT directly.

[FilipŠebík]

This is dead, I fixed the scheme and built the driver, but all it did was heat the output stage mosfets. So its scrapped now...
Lock this thread? If thats a thing