cross conduction idea

[mosfet54]

Yes lazy is both.

At the output meant after mosfets before filter. Think i mentioned it.
output of class d amp.

i tried to change drain voltage to 36V but smth failed and now its not working with 12V too 🙁

*with mosfet driver ir2111
*mosfets are alive :O

doesnt make sense.

 

[Pafi]

At the output meant after mosfets before filter. Think i mentioned it.
output of class d amp.

No. You wrote about a sound card in that post. Class D amp was not mentioned. Try to be clear! Being clear also helps you to understand whats going on.

i tried to change drain voltage to 36V but smth failed and now its not working with 12V too

As I wrote:

Gate to source voltage should be 12 V, not Gate to GND! The way you connected the transistors, at high voltage you can get only damaged parts, not amplifier.

You must not exceed absolute maximum specifications of the MOSFET. Exceeding Gate to Source voltage absolute maximum rating can kill the MOSFET immediately.

But still, Gate voltage must exceed Drain voltage to open the FET, even if Drain voltage is very high. This is the task a high side driver does. Your "gate driver" schematic doesn't.

 

[mosfet54]

No. You wrote about a sound card in that post. Class D amp was not mentioned. Try to be clear! Being clear also helps you to understand whats going on.

No, its more clear than clear.

As I wrote:

You must not exceed absolute maximum specifications of the MOSFET. Exceeding Gate to Source voltage absolute maximum rating can kill the MOSFET immediately.

But still, Gate voltage must exceed Drain voltage to open the FET, even if Drain voltage is very high. This is the task a high side driver does. Your "gate driver" schematic doesn't.

This is clear too, i said Drain voltage, not Gate to source 😕
I am using ir2111 and in its datasheet drain voltage of the up fet is 600V.

whats the point to increase gate to source voltage ? theres no point. 12V is perfect.

i am using irfz44n and 36V is in range.
Do i need to say here that im talking about drain voltage, not gate ?

 

[Pafi]

whats the point to increase gate to source voltage ? theres no point. 12V is perfect.

Nobody told you should increase it. You have to simple achieve it during on state, and never exceed absolute maximum. But none of your schematic achieves it, because in none of them you try to deal with Gate to Source voltage on high side. What you designed are essentially not high voltage half bridge drivers.

This is clear too, i said Drain voltage, not Gate to source

And don't you think there is a relation between Drain (referenced to GND) voltage and Gate to Source voltage in your circuit?

 

[Pafi]

Is there any mosfet driver with 1 input, low dead time for audio, DIP package and 8 pins ?

2 inputs, but otherwise perfect: http://www.irf.com/product-info/datasheets/data/ir2011.pdf

What i know for low dead time is with 2 inputs and many pins.

Is it a problem?

 

[mosfet54]

But none of your schematic achieves it, because in none of them you try to deal with Gate to Source voltage on high side. What you designed are essentially not high voltage half bridge drivers.

ir2111 is high side driver, it seems you are not reading carefully.

what i tried is ir2111 + 36V @ upper mosfet's drain.
its confusing why not working, i have 47u bootstrap capacitor.

upper mosfet gate voltage goes 24V referenced to ground.

 

[mosfet54]

2 inputs, but otherwise perfect: http://www.irf.com/product-info/datasheets/data/ir2011.pdf

Thanks, this is good but its very expensive and need order.
IR2011PBF. - INTERNATIONAL RECTIFIER - Dual MOSFET Driver, High Side And Low Side, 10V-20V Supply, 1A Out, 75ns Delay, DIP-8 | Farnell element14

 

[Pafi]

ir2111 is high side driver, it seems you are not reading carefully.

what i tried is ir2111 + 36V @ upper mosfet's drain.
its confusing why not working, i have 47u bootstrap capacitor.

upper mosfet gate voltage goes 24V referenced to ground.

Oh, so you are talking about a circuit that is not shown here, instead of one of the shown circuits?

Only changing is constant in your communication.

Nobody will tell what the problem is in a circuit that is not shown. You must share information first, and make clear that you changed the topic!

 

[Pafi]

Thanks, this is good but its very expensive and need order.
IR2011PBF. - INTERNATIONAL RECTIFIER - Dual MOSFET Driver, High Side And Low Side, 10V-20V Supply, 1A Out, 75ns Delay, DIP-8 | Farnell element14

You didnt tell you need it for free. If 3 Euro is very much, then be smart and find a cheaper solution. If you know what you really need, then there are many options. Except for free lunch.

 

[mosfet54]

I mentioned that's offtopic.
You are not reading..

Yes, they are options, I asked for 1-1.5 euro driver like ir2111 but with less dead time.

One option is ->

I am thinking of using logic level mosfets and dividing the down side voltage instead boosting the up one.

Offtopic 2. I have another use for my ir2111 -> boosting 12V to 230 or 460V DC (via computer ATX transformer)(I have many of them, maybe 40-50)(i really enjoy this 😀 ) -> then PWM this HV via half or full bridge and this all mess equals to 220V 50hz inverter that im imagining for so long time 😀 and this is 200-300W :O

Offtopic 3. I tested one 250W 50hz old transformer from junk with series bulb in the mains and transformer works but the lamp is ON ?
Is this because its 250W or smth is wrong with the primary winding ?

 

[Pafi]

I mentioned that's offtopic.
You are not reading..

Where??? And why do you think being offtopic is an excuse? Especially for being rude...

Yes, they are options, I asked for 1-1.5 euro driver like ir2111 but with less dead time.

No, you didn't specify any price limit. Sorry for not reading in your mind!

One option is ->

I am thinking of using logic level mosfets and dividing the down side voltage instead boosting the up one.

(This idea is as good as the previous ones.)

Why thinking about the basic requirements and operation is not an option? Why asking how to do is not an option? Why using well known designs is not an option?

Offtopic 2. I have another use for my ir2111 -> boosting 12V to 230 or 460V DC (via computer ATX transformer)(I have many of them, maybe 40-50)(i really enjoy this 😀 ) -> then PWM this HV via half or full bridge and this all mess equals to 220V 50hz inverter that im imagining for so long time 😀 and this is 200-300W :O

This task makes sense, however if you failed to build a low voltage amplifier, then you have a very good chance for failure in this project, plus and an electric shock.

Offtopic 3. I tested one 250W 50hz old transformer from junk with series bulb in the mains and transformer works but the lamp is ON ?
Is this because its 250W or smth is wrong with the primary winding ?

Can you translate "works" and "ON" for measured quantities?

Every transformers have a certain magnetising current and eddie current loss. It can be enough to light a bulb somewhat. The actual value varies very much depending on the technology.

 

[mosfet54]

Where??? And why do you think being offtopic is an excuse? Especially for being rude...

Here and im not rude :|_ook at urself. oFFcourse its an excuse. Im not going to start thread before i make a PCB for this.

only problem i cant figure out is that my amp is very quiet.
..

the duty cycle goes min and max very good, this is not the problem.
the mosfets gates are 0-12V -> good low Rds
..

(little offtopic) 😕

No, you didn't specify any price limit. Sorry for not reading in your mind!

Example of rudeness.

(This idea is as good as the previous ones.)

Explain why?
cross conduction ? no problem, will kill it with dischargers.
High side will get 12V referenced to ground, maybe this is ~6V referenced to source. For logic lvl mosfet this is perfect.

plus and an electric shock.

Death here not just an electric shock.
DC voltage is more dangerous than AC.