MOSFET gate driver signal issue

Thread Starter

jlawley1969

Joined Feb 22, 2021
18
I am trying to make a modified sinewave inverter but I am running into several issues.
I have attached the section of the circuit I am testing it looks like there is alot more going on but I am literally just testing the gate driver aspect and on top of that I am just testing one of the half bridge drivers to see if it works.
I am using a PIC10F222 to output the high and low signals to an IRS2186SPBF gate driver and this is driving 2 IRFI644GPBF.

The images are as follows:
circSchem is the section of the schematic relevant to my problem
circ1 is a physical set up of the circuit(I have tried different arrangement and this has the least amount of noise but the same problem)
circ2 is the gate signal of the low side MOSFET
circ3 is the gate signal voltage of the high side WITHOUT the supply voltage being applied that MOSFET's drain
circ4 is the same signal as circ3 but the supply voltage IS being applied to the MOSFET's drain(I caught the signal as it was refreshing but the complete shape on the left is what is repeated)

I am mostly concerned with the signals seen in circ4 and circ3, why is it when the supply voltage is applied to the drain that I get so much extra signal in my gate. From what I have read briefly I believe it has to do with Miller Capacitance but I don't understand why it is so aggressive. I have seen some ways to combat Miller Capacitance but I was looking for any and all suggestion you have.
I am relatively new to electronics and VERY new to signal electronics so talk to me like im dumb.
 

Attachments

Audioguru again

Joined Oct 21, 2019
3,199
The breadboard photo with too many wires in each intermittent hole has such messy wires all over the place that we (and you) cannot see what connects to what.
Solder the circuit together neatly on a pcb, or soldered together on a stripboard with a few short jumper wires.

Your Mosfets have no part number.
 

Thread Starter

jlawley1969

Joined Feb 22, 2021
18
it ended up being that I needed an pull down resistor on the high side gate driver. It got rid of the mosfet not turning completely off. I even got it to work in the full H bridge, the only thing taking me so long was probably lack of attention to detail haha.1622754825139.png
 
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