Making car amplifier SMPS with tl494 + DC Protection - Page 51 - diyAudio
Go Back   Home > Forums > General Interest > Car Audio

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 19th March 2008, 08:02 PM   #501
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
The IC is using 5v as the reference on pin 2. If you lowered the value of the 47k, it would increase the rail voltage.

It's better to have both the positive and negative feed the regulator unless you're running a bridged amplifier or an amp that pulls from both rails at the same time.
  Reply With Quote
Old 19th March 2008, 08:33 PM   #502
diyAudio Member
 
theAnonymous1's Avatar
 
Join Date: Feb 2004
Location: Anonymityville
Thanks Perry, I think we've got it.

17.5k gives me +/-40v with a 14.4v input. Before it was +/-47.5v.

The amp will either be bridged mono or at least stereo with one channel driven out of phase.

Now, do I need to add an output inductor to each rail since it is regulated now?

Thanks again and sorry if I was any hassle.
  Reply With Quote
Old 19th March 2008, 08:45 PM   #503
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
I'd try it without the filter inductors. You're unlikely to see any improvement by using them. I know that some people will disagree but there are many manufacturers that don't use them and their amps work flawlessly.
  Reply With Quote
Old 20th March 2008, 10:50 PM   #504
diyAudio Member
 
Join Date: Feb 2008
Perry,

I have noticed that you are expert in SMPS and know it by heart...

I have a question (which i have tried to solve, but, since i am no expert...cant solve it without your help)

have a look at this inverter schematic....

there is a TL494 at the high frequency side...and another on at 50hz section...

both error amplifiers are either controlled by LM324 or 50hz TL494...

I need to remove both - LM324 and 50hz tl494...and use two error amplifiers as a voltage regulator and current regulator...

and there is no way i can do it....i have tried to reduce the voltages and i was successfull....but, removing 50hz tl494 just brings the voltages back to full...if both are there, then i can regulate the voltages on both side (high frequency and low frequency sides)


If you can help ....i will be really greatfull...

or if thats not possible to modify, then if you have another TL494 regulated smps circuit...?

one way or another, you are my best bet
i am pretty sure you can help.

Thanks again.

Regards
  Reply With Quote
Old 20th March 2008, 10:51 PM   #505
diyAudio Member
 
Join Date: Feb 2008
PDF file with a schematic.
Attached Files
File Type: pdf !! tl_494 inverter.pdf (34.7 KB, 1099 views)
  Reply With Quote
Old 20th March 2008, 11:03 PM   #506
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
I'm no expert. The experts are on the power supply design forum.

Can you tell me precisely what you've done so far and the results?

You've been somewhat vague about what you're using this for. Can you provide more details?
  Reply With Quote
Old 20th March 2008, 11:16 PM   #507
diyAudio Member
 
Join Date: Feb 2008
well...the first thing i did was to reduce the output voltages at U2 to 44 volts - by changing resistance R29/R30 to lower values and increasing ground resistance R31....i was successfull

Then I reduce the voltages at the high-frequency side
by reducing resistance R42 and increasing resistance R39....
i was successfull in that too...and manage to get 44-volts.

but, since i dont need the low frequency stage, i want to get rid of it and get 44-volts output from U1....

I have also tried to totally remove U2 but, that brings the voltages back to 120v at U1 (power stage DC)

also, I have tried to remove R14 at U1 connected to pin 4...(dont know if it was a smart move) but, it did'nt work...

so, here i am...
  Reply With Quote
Old 20th March 2008, 11:39 PM   #508
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
Did you try changing the 152v Zener before you changed the resistor values for the regulation?


Where does VCC connect in the inverter?


Can you post a photo of the insides? If you have a high res photo, email it to me:
babin_perry@yahoo.com


The transformer in this inverter probalby has a winding ratio that's too high to operate efficiently at 44v.
  Reply With Quote
Old 20th March 2008, 11:40 PM   #509
diyAudio Member
 
Join Date: Feb 2008
no...i never tried to change the zener....i did'nt even know that its a 152v zener....i only knew that its a zener...

here is another part of the schematic...
  Reply With Quote
Old 20th March 2008, 11:42 PM   #510
diyAudio Member
 
Join Date: Feb 2008
power stage schematic.
Attached Files
File Type: pdf tl_494 inverter power stage.pdf (65.6 KB, 982 views)
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Overcurrent, overheat and overvoltage protection for TL494 Janez Power Supplies 17 21st December 2007 03:36 PM


New To Site? Need Help?

All times are GMT. The time now is 09:56 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2