The first thing I saw in the datasheet was a Vcc limit of 40V.

I thought you were working with a few hundred volts?

If so, and if you try this IC, you'll blow the lid right off of it.

You must ensure that the driver IC meets all of your requirements before you connect it, unless you enjoy seeing bright flashes and large clouds of acrid smoke, accompanied by loud "BANGs".

Hi,
The 300vdc is to drive the bridge to convert to 50hz 220vac. This is obtained from the 12v battery through an inverter circuit. The SG3526 would be running from the battery and driving the bridge which would be run from the 300vdc. Both the supplies have common ground. So there is no problem with 40vdc limit.

Thanks.

 

Can we see a drawing of the bridge?
Have you tried driving the transistors with a pulse tranformer?

Hi,

I do not want to use pulse transformer for driving transistors, as, if I used pulse transformer, I could have driven MOSFETs. For driving the transistor, the pulse transformer would need to produce 300vdc for driving the base as I need 300v on the emitter as well, so that 300vdc can be obtained for the bridge to convert 300vdc to 220vac 50hz.

Earlier, I tried to use pulse transformer for driving MOSFET bridge. But I was not successful. Please advise me how to construct, turn ratio, current requirement,etc. of the pulse transformer. I think it should be linear (silicon core) as the bridge will operate at 50hz. Hope to get detailed help from you.

Thanks.

 

This bridge drive circuit is out of a power supply I built but I think this will give you an idea of how it works. The inputs to the SG3526 are not connected, don't know how you will use them. Incorporate the current transformer into the design, when working properly it will save blowing transistors. I used IGBT transistors, much better for the job but FETs can be substituted.
Hope this helps

 

Hi,

Pich, thank you for your circuit. I have already tried that with MOSFETs but I did not get output, so I went to transistors.

A few questions about your circuit:
There was written: "There will be 300 volts potential between 2 of the secondary windings on T3." Why will there be 300v? If 300v came, wouldn't it blow out the gate.

T3 is wound on a torroid. It should be IRON torroid, right?

Since SG3526 is operating at 50hz at 50% duty cycle, the outputs of the SG3526 would be 6v if the Vcc is 12v. When it is fed to the pulse transformer, the outputs would come out as 3v. Wouldn't that be insufficient for the IGBT / MOSFET. Shouldn't the turns be the other way round? 10 turns on primary and 20 on secondary, so we get 12v on the IGBT gate?

You gave only 20 turns. On a linear transformer, would that be sufficient? Plus, wont current rush, as you are using only #22 wire and there is almost no resistance as there are only 10 turns in secondary which has to withstand 300v and in linear mode do you think it is possible? - I think otherwise.
Thanks.

 

Hi,

Pich, thank you for your circuit. I have already tried that with MOSFETs but I did not get output, so I went to transistors.

A few questions about your circuit:
There was written: "There will be 300 volts potential between 2 of the secondary windings on T3." Why will there be 300v? If 300v came, wouldn't it blow out the gate.

Two of the winding drive the low side of the stack and 2 drive the high side a potential of 300 volts exists

T3 is wound on a torroid. It should be IRON torroid, right?

Yes but if you experiment with some you may be able to use powder core

Since SG3526 is operating at 50hz at 50% duty cycle, the outputs of the SG3526 would be 6v if the Vcc is 12v. When it is fed to the pulse transformer, the outputs would come out as 3v. Wouldn't that be insufficient for the IGBT / MOSFET. Shouldn't the turns be the other way round? 10 turns on primary and 20 on secondary, so we get 12v on the IGBT gate?

You gave only 20 turns. On a linear transformer, would that be sufficient? Plus, wont current rush, as you are using only #22 wire and there is almost no resistance as there are only 20 turns?

You should be OK with the turns ratio if you wish you can go 1:1 (20 turns secondary) this is something you can experiment with may need to add more turns to get the proper waveform depanding on the core material you are using.
It would be very helpful to you if you had a scope so you can view the waveform out of the pulse transformer without applying 300 volts. Also the waveform on the secondaries should look like the primary. The secondaries need to be polarized as shown by dots in the shematic.

 

I assume you are building an inverter, here is a link to a very simle circuit that may work for you
http://www.aaroncake.net/circuits/inverter.asp

 

I assume you are building an inverter, here is a link to a very simple circuit that may work for you
http://www.aaroncake.net/circuits/inverter.asp

That very simple inverter circuit has serious problems:
1) Its capacitors are backwards so they explode.
2) Its transistors have avalanche breakdown of the emitter-base junction which creates very high currents in the capacitors and explodes them even if they are installed with the correct polarity.
3) The transistors do not have enough base current.

Look at all the complaints in the very long threads in the forum over there about it.

 

Thanks audio guru didn't read the details
Tahmid can you post a diagram of your circuit?

 

Hi,
Pich, I am not concerned about linear inverter as I have made that and am using in my study room.
Here I am concerned about a switched-mode inverter. I have made the SMPS battery charger and the boost circuit via ferrite transformer(50khz frequency), which converts 12vdc battery supply to 300vdc, which has to be converted to 220vac 50hz through full bridge circuit. This full bridge circuit is the part where I am stuck and require help.I have tested with IR2110, IR2181, IR2118, pulse transformer, p-channel n-channel mosfet with level shifting, transistor,etc. but could not be successful till today, though I have lost more than 35 mosfets / transistors / drivers.

Thanks.

 

Glad you did it. What did you do to make it work?

 

Glad you did it. What did you do to make it work?

Hi,
Making a linear inverter is very easy. I used SG3525 as oscillator, 2 MOSFETs operating in push pull topology and a transformer and extra winding for battery charging using the same transformer. Hi-lo cut out is there for efficient battery charging and mains sensor, using TLP620 and transistors / relays, for automatic switch-over. I made upto 600VA linear inverter.

Now I am striving for making SMPS inverter as I do not like linear mode because of bulky transformer and excessive heat.

Thanks.

 

Hi,

This full bridge circuit is the part where I am stuck and require help.I have tested with IR2110, IR2181, IR2118, pulse transformer, p-channel n-channel mosfet with level shifting, transistor,etc. but could not be successful till today, though I have lost more than 35 mosfets / transistors / drivers.

I have finally made the full bridge circuit with MJE13009. The problem was cross-conduction. Since I could not get hold of SG3526, I used PIC 12F675 to generate a quasi-sine waveform: 8ms on, 2ms off and vice versa.

I would like to thank all who helped me. Thank you.