Finished Car Amplifier schematic + PCB based on Kenwood KAC-716

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Would this be a suitable core for a 300W high current amp? I'm wanting to build a 2 channel old school "cheater" amp that can go down to 0.5 loads. Power at 4 ohms to be around 20 Wrms per channel. I'll go with a unregulated supply of around +/-15 volts. At 1 ohm mono I would like about 300 Wrms.
 

Attachments

  • CORE.JPG
    CORE.JPG
    32 KB · Views: 326
The below quote is from Perry's web site. I've Googled around, but cannot find any references to the 20% winding factor for toroidal cores. What is the rationale for it? Is it a known good balance between copper losses and good magnetic coupling between primary and secondary? At face value it makes me think about the primary copper losses more than anything.



OK, now that you basically know how much copper you need (considering the duty cycle, maximum power and current draw), you have to have a core that can hold the primary and secondary windings. Many times, the primary and secondary will have approximately the same amount of copper on the primary as on the secondary. If you have a transformer with a 1:3 ratio, the length of wire for the secondary will be three times as long as the wire on the primary but the current passing through it will be 1/3 as much so the circular mils of the secondary will be 1/3 that of the primary. For this supply, the secondary uses a single 14g wire where the primary uses three parallel 14g conductors. What this means is that the core will have to hold approximately double the copper used for the primary alone. For toroidal cores, the 'winding factor' is generally 0.2 (20% of the window area filled with copper). It can be more or less but this is typically what's used in the various calculations.
 
if you really need feedback, it would be done pretty much the same as with SG
find one that has TL and has feedback... I think you will only need hand full of components more for that

TL494 has DTC pin 4, Feedback pin 3, 4 inverting/noninverting pins 1,2,15,16, I've attached image from datasheet.

I'm confused which all pins are for U an I control???
 

Attachments

  • tl494.PNG
    tl494.PNG
    19.9 KB · Views: 420
The 0.2 winding factor is for the primary. It's not critical.

Page 4:
http://www.mag-inc.com.cn/file library/products/ferrite/power_design.pdf

That's a really nice tech paper. What I find most interesting is how little capacitance and inductance is required at these higher switch frequencies. In one of my SMPS examples I calculated 4.9uF and 1.4mH. Due to the waves being square instead of a sine wave, once rectified there's not much left to do because its basically DC at that point. We just need to clean up the ringing and noise. I also see why having a perfect 50% switching duty cycle for the MOSFETs is so critical. These SMPS are very interesting beasts.
 
protection unit

Hello risto..its great work you have done here.i.have seen all 3 pcb and schemes.all are nicly done.the only thing i am not able to understand is the protection unit of the amp .it will be very helpfull if you post a conection drawing of protection unit with amp and smp..regards sohail
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.