Well i hope this works. This is a very basic design i'm just trying to get the outputs of the IR2113 to be square waves. Any advise would be great, I havn't set up the output filter yet.
http://i607.photobucket.com/albums/tt155/brianland/class-d3.jpg
http://i607.photobucket.com/albums/tt155/brianland/class-d3.jpg
http://i607.photobucket.com/albums/tt155/brianland/brian1.jpg
Maybe easier to look at it this way. We spent most of the day trying to think of what we are doing wrong with this circuit and why are IR2113 isn't working, we've tryed a few different chips to see if one was blown. Anyway if anyone has any ideas please let me know. also i forgot to label one of the chips but its IR2113.
Thanks
Brian
Maybe easier to look at it this way. We spent most of the day trying to think of what we are doing wrong with this circuit and why are IR2113 isn't working, we've tryed a few different chips to see if one was blown. Anyway if anyone has any ideas please let me know. also i forgot to label one of the chips but its IR2113.
Thanks
Brian
7ormore!
What do you mean it "isn't working"? What do you expect from this circuit?
The schematics are not identical, on brian1.jpg the low side MOSFET gets a -25 V source voltage, wich is wrong.
If you want this to be an amplifier (or any useful circuit), then the schematics are basically wrong. But IR2113 should work in class-d3.jpg circuit (more or less).
What do you mean it "isn't working"? What do you expect from this circuit?
The schematics are not identical, on brian1.jpg the low side MOSFET gets a -25 V source voltage, wich is wrong.
If you want this to be an amplifier (or any useful circuit), then the schematics are basically wrong. But IR2113 should work in class-d3.jpg circuit (more or less).
Pafi said:
Sorry i wasn't sure how to diagram the voltage source. This is all being done on breadboard. the power mosfets are being driven from a DC generator while the chips are being powered by the cadet board.
Eva said:
To clarify you mean i shouldn't use LM311 to compare my inputs to get a digital output? The other op-amp is LT1056 which i am using to invert the signal. I can see how these would cause gate delays. I could easily replace LT1056 with an NOT gate but i'm unsure what i would use to replace LM311
Thank you for the help as u can tell i'm a newbie, any help is more than welcome. Also if you want any pictures of anything that I am not making clear please let me know.
This doesn't tell anyting. OK, by the cadet board, but how? COM (and VSS) of the IR2113 should be connected directly to the source of the lower MOSFET!
I repeat: What do you expect from this circuit? What is this supposed to be? It's usable for testing the functionality of the IR chip, but nothing else.
Try to think it over what signal do you want on the load, and for that what is the appropriate switching topology (yours is good for nothing), and for that what are the neccessary gate-signals!
Pafi said:
For this circuit i am trying to build a class-D amplifier, right now though i am just trying to make sure i have the IR working properly, what i want to show by the end of the semester is a half H-bridge amplifying the input sine wave. I realize i need to design a filter for it too. I would do a full H bridge but i'm running out of time.
Thanks
Brian
Workhorse said:To thread starter,
Go and learn some basics first, you need to learn alot to get the things done in right manner.
Sorry i have been researching this quite a bit and i also built a scematic of the class-d which worked very well in P-sim, however i'm running out of time and have to present something soon.
I guess i spoke to soon the problem i'm having is with the high output the amplitude is correct but the frequency is only at 44kHz when it should be a 298KHz. The good news is that the low is correct and the mosfets are amplifying the signal. I will be working all day on this to try and figure it out.
Thanks
Brian
Thanks
Brian
http://i607.photobucket.com/albums/tt155/brianland/class-d4.jpg
This is an update of what has changed in my design. I now have good outputs for HO and LO for IR2113. LO outputs from 0-20V and the HO output is from 0-20 of the inverted signal. I'm worried about gate delay and if my LC filter will work.
Thanks to everyone for the help
Brian
This is an update of what has changed in my design. I now have good outputs for HO and LO for IR2113. LO outputs from 0-20V and the HO output is from 0-20 of the inverted signal. I'm worried about gate delay and if my LC filter will work.
Thanks to everyone for the help
Brian
All people who have replied to you in this thread have our own working amplifier designs.
If you continue ignoring our advice you are not going anywhere.
The schematic contains almost the same mistakes: No level shifting, not caring about timing on HIN/LIN splitting, +/-15V fed to HIN and LIN, etc.. Not even related to class D, just to basic electronics...
If you continue ignoring our advice you are not going anywhere.
The schematic contains almost the same mistakes: No level shifting, not caring about timing on HIN/LIN splitting, +/-15V fed to HIN and LIN, etc.. Not even related to class D, just to basic electronics...
I'm sorry if i came off as not caring about level shifting and delay caused by the op amps i deffinitly do care about that. I was debating on replacing the two op-amps with the IC TL494CN it seems to do the job of both the op-amps with out the problem of level shifting and the gates delay. The only reason i'm currently using this design is because this is the layout my advisor suggested to use.
I do appeaciate all the help
Thanks
Brian
I do appeaciate all the help
Thanks
Brian
You will find that TL494 does not suit your needs well.
LM311 is ok as a comparator. Note that there are other common comparator ICs with faster response like LM319 or TL3016 (to name two that I have used).
For level shifting, which means to change the ground referenced logic output from the comparator to the negative rail referenced logic signals needed by the IR2113, the simplest solution is to use a PNP transistor in common-base configuration (fed an emitter current and you will get an almost equal collector current with very fast response). You can use a fast optocoupler like 6N136 too.
Then you must use 74HC fast logic gates (or a fast transistor circuit, but this is not recommended) to generate the complimentary HIN and LIN signals so that the delay between them is only a few nanoseconds and they don't overlap in the high state (otherwise the circuit would self destruct). An op-amp may take several microseconds to respond when used as a logic inverter, which is absolutely not acceptable.
If you advisor told you to use an op-amp as a logic inverter, you should not trust him much... This is a really big mistake.
LM311 is ok as a comparator. Note that there are other common comparator ICs with faster response like LM319 or TL3016 (to name two that I have used).
For level shifting, which means to change the ground referenced logic output from the comparator to the negative rail referenced logic signals needed by the IR2113, the simplest solution is to use a PNP transistor in common-base configuration (fed an emitter current and you will get an almost equal collector current with very fast response). You can use a fast optocoupler like 6N136 too.
Then you must use 74HC fast logic gates (or a fast transistor circuit, but this is not recommended) to generate the complimentary HIN and LIN signals so that the delay between them is only a few nanoseconds and they don't overlap in the high state (otherwise the circuit would self destruct). An op-amp may take several microseconds to respond when used as a logic inverter, which is absolutely not acceptable.
If you advisor told you to use an op-amp as a logic inverter, you should not trust him much... This is a really big mistake.
You will find that TL494 does not suit your needs well.
LM311 is ok as a comparator. Note that there are other common comparator ICs with faster response like LM319 or TL3016 (to name two that I have used).
For level shifting, which means to change the ground referenced logic output from the comparator to the negative rail referenced logic signals needed by the IR2113, the simplest solution is to use a PNP transistor in common-base configuration (fed an emitter current and you will get an almost equal collector current with very fast response). You can use a fast logic optocoupler like 6N137 too.
Then you must use 74HC (or similar) fast logic gates (or a fast transistor circuit, but this is not recommended) to generate the complimentary HIN and LIN signals so that the delay between them is only a few nanoseconds and they don't overlap in the high state (otherwise the circuit would self destruct). An op-amp may take several microseconds to respond when used as a logic inverter, which is absolutely not acceptable.
If you advisor told you to use an op-amp as a logic inverter, you should not trust him much... This is a really big mistake.
LM311 is ok as a comparator. Note that there are other common comparator ICs with faster response like LM319 or TL3016 (to name two that I have used).
For level shifting, which means to change the ground referenced logic output from the comparator to the negative rail referenced logic signals needed by the IR2113, the simplest solution is to use a PNP transistor in common-base configuration (fed an emitter current and you will get an almost equal collector current with very fast response). You can use a fast logic optocoupler like 6N137 too.
Then you must use 74HC (or similar) fast logic gates (or a fast transistor circuit, but this is not recommended) to generate the complimentary HIN and LIN signals so that the delay between them is only a few nanoseconds and they don't overlap in the high state (otherwise the circuit would self destruct). An op-amp may take several microseconds to respond when used as a logic inverter, which is absolutely not acceptable.
If you advisor told you to use an op-amp as a logic inverter, you should not trust him much... This is a really big mistake.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.