Dear All,
My english is not soo good , so plz bear with it.
I have 2 projects on Car amplifiers based on Class-D .
1) 2.1 Channel Class-D based 100W Car amplifier
Sub: 8 ohms, Sat: 4 ohms
2) 2.1 Channel Class-D based 200W Car Amplifier
Sub & Sat similer
I had worked previously on different audio projects but never worked on SMPS / DC-DC converter or Class - D. So plz consider me as an beginer.
Can any one suggest me a starting point from where I can begin my project.
So any sort of information will be helpul but do reply to this thread.
My english is not soo good , so plz bear with it.
I have 2 projects on Car amplifiers based on Class-D .
1) 2.1 Channel Class-D based 100W Car amplifier
Sub: 8 ohms, Sat: 4 ohms
2) 2.1 Channel Class-D based 200W Car Amplifier
Sub & Sat similer
I had worked previously on different audio projects but never worked on SMPS / DC-DC converter or Class - D. So plz consider me as an beginer.
Can any one suggest me a starting point from where I can begin my project.
So any sort of information will be helpul but do reply to this thread.
I had majorly worked on MCU based audio system where something like remote decoding , Volume controlling (digitally) , phase / Frequency changing , Switch sensing ,LED blinking , LCD displaying are required but do not have any designing experience on SMPS/Class-D based systems. Yes ,
I do kno the theroy of opperation & also worked on Class - AB,H,G (TDA 7296 & TDA 7294 etc) but never with " D ". I had only tested some samples
on lab.
So I am a new commer on Car amplifiers .
By reading some threads I came to kno that there are two basic parts on any Car Amplifier system ---- 1) 12V to required Voltage level Dc-DC converter
2) Amplifier Section ( Class - D mostly preffered for Cars).
Now for Dc-Dc converters ------ Switching IC , Transformer , Swithing Mosfet/Transistors , opperating frequency are most serious thing & obiously layout technique.
What are the major issues that one should keep in mind while selecting these items?? & if possible plz tell me y??
For layout techniques , I kno its a trail & error method but then also any suggestions?? Any reffence designs??
Any special specification of such converters that onw should keep in mind while designing??? Any precaussion??
If I had missed something then plz add
For Class-D section -------- Class - D IC , output Mosfet , output Filter circuit, Opperating frequency , Minimising EMI ,THD , nosie level etcs are serious issues.
Again the same questions.
Offcurse the module should be cost-effective also
I know it is time consuimg but do reply.
I do kno the theroy of opperation & also worked on Class - AB,H,G (TDA 7296 & TDA 7294 etc) but never with " D ". I had only tested some samples
on lab. So I am a new commer on Car amplifiers .
By reading some threads I came to kno that there are two basic parts on any Car Amplifier system ---- 1) 12V to required Voltage level Dc-DC converter
2) Amplifier Section ( Class - D mostly preffered for Cars).
Now for Dc-Dc converters ------ Switching IC , Transformer , Swithing Mosfet/Transistors , opperating frequency are most serious thing & obiously layout technique.
What are the major issues that one should keep in mind while selecting these items?? & if possible plz tell me y??
For layout techniques , I kno its a trail & error method but then also any suggestions?? Any reffence designs??
Any special specification of such converters that onw should keep in mind while designing??? Any precaussion??
If I had missed something then plz add
For Class-D section -------- Class - D IC , output Mosfet , output Filter circuit, Opperating frequency , Minimising EMI ,THD , nosie level etcs are serious issues.
Again the same questions.
Offcurse the module should be cost-effective also
I know it is time consuimg but do reply
.I have not been able to cover up all of the things but had cover up to Fan Driving circuit.
Your job is excellent & yes , its very helpful for any beginner . But some details that I would like to know , is about the Switching FET selection part & Layout .
You havnt uploaded layout of the board ( only top overlay is there ), all though from pictures it seems to be very compact . If possible for you then plz upload its top,bottom
layer. It will give me or any beginner a good idea for component placing & track width selection (specially on Switching section ).
One thing also , can plz elaborate on the Switching FET selection part & there major issues like you had explained on TL594 & power transformers.
Thanks for replying.
Your job is excellent & yes , its very helpful for any beginner . But some details that I would like to know , is about the Switching FET selection part & Layout .
You havnt uploaded layout of the board ( only top overlay is there ), all though from pictures it seems to be very compact . If possible for you then plz upload its top,bottom
layer. It will give me or any beginner a good idea for component placing & track width selection (specially on Switching section ).
One thing also , can plz elaborate on the Switching FET selection part & there major issues like you had explained on TL594 & power transformers.
Thanks for replying.
The FET selection isn't critical. It generally depends on the power you'll draw from the power supply. If you're only going to need 200 watts, IRFZ44s will easily suffice. If you're going to intermittently need 800 watts, the IRF3205s are a minimum.
One of the most important rules in the layout is to keep the circuit paths (traces) for the switching circuits short. If this supply was to be limited to 200 watts of output, I would have had the drive circuits a bit closer to the FETs. Since it was designed to deliver significantly more power, this meant that the drive circuit had to be further away (to allow heavy copper traces to be used to connect the B+ to the transformer, the transformer to the FETs and the FETs to ground).
The circuit paths for the B+ and ground connections have to be very wide and as short as possible to reduce the resistance. At full output, this supply can draw over 100 amps and this can result in heating and damage to the copper and eventually to the board if the resistance isn't kept as low as possible.
I have no plans to post the entire layout at this time.
One of the most important rules in the layout is to keep the circuit paths (traces) for the switching circuits short. If this supply was to be limited to 200 watts of output, I would have had the drive circuits a bit closer to the FETs. Since it was designed to deliver significantly more power, this meant that the drive circuit had to be further away (to allow heavy copper traces to be used to connect the B+ to the transformer, the transformer to the FETs and the FETs to ground).
The circuit paths for the B+ and ground connections have to be very wide and as short as possible to reduce the resistance. At full output, this supply can draw over 100 amps and this can result in heating and damage to the copper and eventually to the board if the resistance isn't kept as low as possible.
I have no plans to post the entire layout at this time.
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