Babysteps of 1kW Class D Rookie Amp

[ChocoHolic]

Basically I am a fan of 3D-P2P constructions. But my handmade schematics and handmade routing plans were somehow annoying. And – frankly speaking- a relict of the last century. OK, even if learning is hard in my age... No way around starting my first babysteps in CAD. I decided to use the cost free Eagle Light. And my current class D project was exactly right for that, so I went for a 2 layer PCB with ground plane structure.

Schematic first. It is an self resonant hysteresis design. A fast comparator (LM160) with inverting/noninverting outputs to generate also the signals for a full bridge. Each halfbridge is using a IRS 20954 driver and two IRFB52N15D MOSFETs.
The missing connection in the schematic between upper source and lower drain will be a wire, because I need to do current measurements in this wire for optimized dead time adjustment. Each PCB is just one half bridge with comparator, but without output filter. For a full bridge the comparator is only needed on one PCB and delivering the signals for both half bridges. So far my theoretical plans... Reality will show....

[ChocoHolic]

Today I received the PCB samples and was quite pleased about the quality.
I got samples with 35 micrometers copper thickness and with 70 micrometers.
Somehow I feel more comfortable with thicker copper especially for my 1kW full bridge, with max. currents around 50A...

Component side:

[ChocoHolic]

Ground side:

[Eva]

Uhm, this is a promising project... Go on with it. I wish I could have double-sided hole-plated PCBs with solder mask and silkscreen as yours delivered quick and cheap here Currently I have to print, expose, reveal, etch and drill my own double sided boards (no plating )

BTW: My new 2500W low-frequency class D amplifier powered with 416V directly from the output of a PFC is working and almost ready. I may post some pictures soon for you to see. I have been really scared sometimes during the development because the capacitor bank at the output of the PFC stores around 200 joules

[Markus2006]

Eva, we want to see this monster .
Why do you have to manufacture the boards on your own? If you have Gerber files, I can help you. But this also shouldn't be a problem in Madrid.
What does "PFC" stand for?

Marek

[Nisbeth]

Originally posted by Markus2006

What does "PFC" stand for?

PFC = Power Factor Correction


/U.

[ChocoHolic]

Originally posted by Eva
Uhm, this is a promising project... Go on with it. I wish I could have double-sided hole-plated PCBs with solder mask and silkscreen as yours delivered quick and cheap here Currently I have to print, expose, reveal, etch and drill my own double sided boards (no plating )

BTW: My new 2500W low-frequency class D amplifier powered with 416V directly from the output of a PFC is working and almost ready. I may post some pictures soon for you to see. I have been really scared sometimes during the development because the capacitor bank at the output of the PFC stores around 200 joules

...200 joules, so you have something like 2200uF at 416V.. Oh, yes... you designed your inrush current limiter for obvious reasons.
...and just to mention... don't let your screw driver drop into the running circuit.... or fry your necklace... it's a good habit to be slightly scared, when handling such energies.

My PCB... fast? ...delivery time is 2 weeks. And it is not cheap at all, even in China. But living in China is cheap, so I can spend more money on my hobby. And honestly I start to enjoy professional PCBs, even if expensive. It is fantastic: You play around at the computer with some CAD software, make some schematic, some virtual pictures..., then let the machine generate some mysterious data files and send them out (OK, I first had a look to them with a gerber viewer). Like from wizzard's hand some weeks later you get the real thing!!! And it is really exactly what you wanted to have! I love it!
Aren't there PCB companies in Spain? Or is it mostly a matter of money? How much would it be ?

[Markus2006]

ChocoHolic,

How much did you pay for your board? I assume it is smaller than 8x10cm. I may ask my company how much would they charge for such a board. They have standard term of 5 days but there is an express option too (more expensive).

Marek

[Gorilla]

For PCBs I use Olimex. Even from New Zealand its only about NZD$70 (about 36 Euro equivalent) including freight.

Cheaps as chips we say down here

[Markus2006]

With my company, if you'd order 1 board (1dcm2), the price would be < 24Euro. But if you order >= 10 boards, the price would be about 10 Euro.

Marek