need help with ir2110 mosfet gate driver

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danish.umer.k

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i m designing a full bridge pure sine wave inverter and using ir2110 mosfet gate driver. i have connected the circuit as shown in the attached picture. the problem is that low side is working fine but output at high side is not switching at all but remains at a constant level of supply voltage. i tried to test the circuit by connecting the high side input pin of the driver to ground and supply voltage manually but to no avail.
i need to solve this problem urgently because i have only a few days before the deadline to finish this assignment.
here is the link to the schematic
https://obrazki.elektroda.pl/36_1334600946.jpg
 

hello danish, your circuit look ok but what type of diode fo you used their?
 

Hello friend!

I have same problem!

At low side it is OK! At high side, the output only show a constant voltage, usualy is equal to Vcc 12V supply.

Any solution for this problem?

Please see may post, and my example:

https://www.edaboard.com/threads/250505/

Thanks for the help.

Basofias
 

hello kabiru,

This is shoaib... we have the same problem that we are not getting high side pulses at output of IR2110.

The diode is not available to us as in circuit so we are using IN4007... is it alright??

Actually we are using in PWM Sine wave inverter.... using two IR2110!!!

We are using IRF840 MOSFET...

Please reply fast..
 

Since you're using it with SPWM, I assume you're working with high frequency.

If the high side is pulsed with 50Hz, 1N4007 diode is okay.

Connect a 1k resistor from gate to source of each MOSFET.

Are you testing the voltage of high side pulse with no load? If so, connect a load and measure the voltage and pulse across the load, instead of just observing the high side output.

But, if you must check high side pulse, remove the MOSFETs. Connect VS (pin 5) to ground and measure/observe the pulse/voltage from pin 7 to ground. You can see the pulse then. Remember to remove the connection of VS from ground before reconnecting the MOSFETs again.

Hope this helps.
Tahmid.
 

Hi all
I think the value of bootstrap capacitor is low you'd better to increase it as large as 100u .
Best Wishes
Goldsmith
 

Hello everyone, 10uf and it's working fine now but 22uf will also work too.
 

Dear Tahmid
Hi my friend . as you can see at the attachment of original poster , the value is 2.2u . is that enough ? of course no . it is the reason that i suggested 100 u . don't forget that each capacitor has a leakage resistor in parallel . so if the value be low , it will has two disadvantage : 1- decreasing the efficiency , because the H side will go to the linear region . and 2 - it can't keep the charge for long times .
Best Wishes
Goldsmith
 

For 50Hz, I've tested with 4.7uF all the way upto 68uF. All of these worked. 2.2uF works for smaller MOSFETs (with lower gate charges and lower gate capacitance).

But it's better to use larger values. 10uF may be more than enough.

100uF should work, although such a large value is not needed with around 50% duty cycle and 50Hz frequency, and one MOSFET (as shown in post #4) (with not too large a gate capacitance) is being driven.
 
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You can design it . simply ! to design this capacitor these specifications are most important : 1- ciss 2- leakage 3- ESR and ESL 43 the maximum time that it should give current .
 

Really thanks bro Tamhid,

we have gotton the all 4 pulses at the output of driver circuitry by Grounding pin 5...

But there is still a bit problem we are facing that when we apply those 4PWM pulses to gates of MOSFETS we are not getting desired output(i.e. pattern of resultant pulses equivalent to sine wave).

So, what should we do??? Is there any need of isolating transformer or any other thing or we can directly apply those pulses that are at that output of driving circuitry IR2110 to MOSFET's...?

Please reply!!!!!
 

Can you post a picture of the output signal you are getting and also of the driving signal?

Did you use the LC filter?

Using isolating transformer is really up to you. You have to decide if you need it or not.
 

Hi again
Can you show us , that what kind of signal you're getting in out put , exactly ?
 

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