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H-bridge inverter circuit using ir2110 mosfet driver

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Hi,
From post#10
you need a fast capacitor, usually a ceramic ot foil one
Mylar is foil. Thus: yes.

Klaus
 

hello,

Why do we need to change the eloctrlytic caps with fast caps used for bypass and bootstrap circuit? Thank you!
 

A small 2.2 uF standard electrolytic cap has an ESR of several ohms, it's not behaving as a true capacitor at 10 kHz or higher pwm frequency. That's particularly problematic in a circuit that lacks any gate resistors. I would add appropriate gate resistors, or a resistor diode circuit, as mentioned before and then check the gate waveforms.
 

A small 2.2 uF standard electrolytic cap has an ESR of several ohms, it's not behaving as a true capacitor at 10 kHz or higher pwm frequency. That's particularly problematic in a circuit that lacks any gate resistors. I would add appropriate gate resistors, or a resistor diode circuit, as mentioned before and then check the gate waveforms.

Hi FvM,

Thank you for that information. What values of resistors are often used in this resistor diode circuit?
 

Good day! I pcb'ed the circuit I posted from post#1 tested it with a scope. Fortunately no components were burned but there was no output coming from the inveter. The driver's HO and LO has an output though. here are the pictures of my setup:

setup1.jpgsetup 2.jpgsetup 3.jpgsetup 4.jpg

What should I check with first to troubleshoot this? Thank you!
 

Hi,
What should I check with first to troubleshoot this?
Power supplies, correct connections, signal flow.

Klaus
 

Hello,

I tried to measure the output with a dmm in the dc range and I measured a dc output from inverter with the driver still going. Is that okay?
 

Hi,

use a scope to follow the signal path.

Klaus
 

Hi,

use a scope to follow the signal path.

Klaus

Will do that.

Anyways, I have drawn a new version of schematic and pcb layout design and I tried to incorporate the suggestions I've received so far. Please kindly check again for any issues. Thank you!

new schem+pcb1.PNGnew schem+pcb2.PNG
 

Hi,

I think it´s OK the way it is.
No need to change anything.

****

But it wasn´t me if I don´t have any hints for improvements. ;-)
* you work with some kind of high voltage, thus I recommend to keep minimum clearance as high as possible. (wire width underneath the MOSFETs, clearance of N$10 close to TP4, clearance at C3 / C5......)
* don´t use the current carrying traces as sense lines. Use extra sense traces directly from the shunt.
* I´d move the shunt and place it in parallel to U$1. This shortens the power traces and improves GND plane
* I recommend a two layer design, where the complete bottom layer is GND. Without other signals.
* I´d interchange to position of C4 and the 5V_pad in a way that you can route the GND wire underneath the IC to C4. This improves C4 wiring and relaxes SD and LIN wiring.
* please check R3 and R4 values. I assume the lower value resistor should be connected to GND.

Klaus
 
Hello,

Can you expound on these?
Hi,

*Use extra sense traces directly from the shunt.
* I´d move the shunt and place it in parallel to U$1.


Klaus

Please bear with me thank you!
 

Hi,

like this.
Modif.PNG

Btw: no wirewound shunt.

Klaus
 
Good day! I tried the new pcb layout here are the results:
As you can see the blue trace is the gate pulse of the lower mosfet and the yellow trace is the gate pulse of the high mosfet.
DS0065.PNG
This trace though is from the output of inverter output.PNG without any input voltage to the inverter I'm seeing an output.
DS0064.PNG

When I removed all the connection and connected everything from the start, this time I double checked it, this is what I get from the oscilloscope:
DS0009.PNG

The gate pusles are the blue and yellow trace. The purple trace is the inverter output(this time there's 120v ac input from mains).

Also, when I added the resistor diode circuit, the gate pulses have oscillation which is not present when I only have a gate-source resistor, why did this happen?

What could be the problem of my circuit? I checked both of the sub circuit individually and they are working fine. Please help me address this issue. Thank you!
 
Last edited:

Hi,

please take a photo of the PCB with all the connections. High resolution, so that we can trace every wire.

Klaus
 

hello these are the photos of my set-up:

here is the inverter
1.39.jpg1.36.jpg1.45.jpg1.50.PNG

here is the oscillator( don't mind the IR2110 here. It's from my old design where I separated the driver and the mosfet):
1.29.jpg1.34.jpg1.51.PNG

power supplies: upper supply is 12v and the lower supply is 5v.
1.24.jpg

my connections(the sd pin is permanently connected to ground by a switch)
1.4.jpg1.2.jpg1.19.jpg1.20.jpg1.25.jpg1.27.jpg1.35.jpg1.38.jpg1.40.jpg1.42.jpg
1.47.jpg1.49.jpg1.41.jpg

output:
1.37.jpg1.48.jpg
 
Last edited:

Hi,

It all seems they have different cabling. Impossible to find out which one is the picture with failing function. And I can't find a single picture which shows "all" the wiring.

Let's choose another approach:
I assume the low side is working, but the high side not.
Thus use a scope an show three channel in one picture: all measured directly at the driver pin wrt GND. Take care, there may be high voltage.
* VS
* VB
* HO
--> show us the picture

Now I see three possible results:
1) HO is not switching, allways close to GND
2) HO is switching with 12V amplitude (0V / 12V)
3) HO is high voltage switching (0V / >50V)

Do the next scope measurement according the result before:
1)
* IN
* LO
* HO

2) and 3)
* high side Mosfet gate
* high side Mosfet source
* high side Mosfet drain

Klaus
 

Hi,

It all seems they have different cabling. Impossible to find out which one is the picture with failing function. And I can't find a single picture which shows "all" the wiring.

Let's choose another approach:
I assume the low side is working, but the high side not.
Thus use a scope an show three channel in one picture: all measured directly at the driver pin wrt GND. Take care, there may be high voltage.
* VS
* VB
* HO
--> show us the picture

Now I see three possible results:
1) HO is not switching, allways close to GND
2) HO is switching with 12V amplitude (0V / 12V)
3) HO is high voltage switching (0V / >50V)

Do the next scope measurement according the result before:
1)
* IN
* LO
* HO

2) and 3)
* high side Mosfet gate
* high side Mosfet source
* high side Mosfet drain

Klaus

Hello KlausST,

What do you mean by IN?
 

Hi,

Sorry for beeing not clear: IN --> LIN, HIN

Klaus
 

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