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IR2184 gate driver questions

Thread starter #1
Hello people.

I am designing an power inverter.

My idea is transform 12VDC in 120VAC@60Hz.

I will make a signal PWM at 25Khz comparing a triangle wave and a sini wave. OK.

But, to make things simpler in the beginning, I am testing with an static root wave at 25Khz provided by a 555 IC.

I threw this signal on a IR2481 gate driver to switch my two IRFP460 mosfets.

So I started with a basic circuit:



This one is working very well. I am using a single power supply with 12VDC. Look the all the power lines and grounds are the same.

The signal at my gate is ~12V. Nice:



And measuring the voltage across the resistor I came with this:



12Vp.p. It looks that is working. :D.

BUT.....

Lets say that I need to work with to separated power supply. One will be my power supply for the control circuit (12V).

Lets consider that I will use another power supply with 12VDC to power the mosfets and capacitors....

So now I have to power that has different ground lines......

My problem is the COM PIN of the IR2184. Accordingly to the datasheet, I need to connect it to the ground of the "HIGH" power supply. When I say "HIGH" I am referring to the power supply that feeds the mosfets.

In this example, the power supply is 12V, but it can be 24V, 100VDC..... I do not know yet.....

I connect the COM PIN to there and what happened? My IR2184's burned... twice........

What is the correct way to connect the two power supply's and my control circuit?

bye
 

alec_t

Well-Known Member
Most Helpful Member
#3
I connect the COM PIN to there and what happened? My IR2184's burned..
Did you have the COMs of both supplies connected together?
 

ronsimpson

Well-Known Member
Most Helpful Member
#4
I modified you drawing.
100V on the MOSFETS.
12V on the IR2184.
Removed +5V on /SD pin. left it open.

See data sheet.

The two power supplies have a common ground.
 
Thread starter #5
I modified you drawing.
100V on the MOSFETS.
12V on the IR2184.
Removed +5V on /SD pin. left it open.

See data sheet.

The two power supplies have a common ground.
I do not know if helps....

Well, I changed the output from 555IC to 5V, providing 5V at VCC of teh 555 IC....

Now, my third IR2184 did not burn... but when I turn ON the mosfet's power supply, only the upper one become very very hot..... and I turn it off....

I connected the circuit with two ATX power supply, like this:

P.S: I forgot to add the resistor on the gate, but on my circuit, I added two 22 ohms resistors. Each one to each gate.

http://img.photobucket.com/albums/v222/ahhh/circ-1.jpg

OK. I just burnt the third IR2184.... I need to buy more tomorrow.......

Well, accordingly to the datasheet , the SD PIN must be connect to 5V?

I will try your circuit... This one is different of all I have already tried.....

In a few days i will update everyone....

Thanks......
 

ronsimpson

Well-Known Member
Most Helpful Member
#6
Well, accordingly to the datasheet , the SD PIN must be connect to 5V?.
It has a resistor inside the IC that pulls the pin to +5V if you do not connect it. You could connect to VCC.

Well, I changed the output from 555IC to 5V, providing 5V at VCC of teh 555 IC.....
VCC should be between 10 and 20 volts. Not 5 volts.
I think you were driving the IR2184 with a 555IC and now you drive it with 5V. You much have a AC input like from a 555. You can connect the input to ground but you can not connect it to a + level for more than a short time.
 

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