All SMD Class D AMP

I have been thinking about creating an All SMD component Class D amplifier. The purpose would be to keep a totally clean back side of the PCB, so that mounting the amp to a heatsink or an aluminum plate would be as easy as just using a foam heatsink spacer in the full size of the PCB, with maybe a single or 2 screws as a safety measure if the adhesive should somehow slip over time.

I have over the last month been in the process of changing to KiCad 6.0, having been used to some old student versions of Protel/Altium.

It took a bit of time in the beginning, but I feel I have gotten pretty used to the new tool, I’m getting more and more familiar with some of the smart features. It is for sure a very powerful tool and it is simply almost unbelievable that this is all for free. Big thanks to the team behind it.

As a new thing, I will also implement protection functionalities based on an ATMEGA328p, writing the code in Arduino.

The size is limited to 100 x 55 mm as I want to use a small 100 x 60 x 10 mm heatsink from Aliexpress

The top picture on this page shows the very first version where the schematic is not finished yet, but where the larger main components have been placed. As can be seen, there will not be room to spare, and it’s not even for sure there will be room enough. The MosFets used are by now in D2PAC, but it would save a lot of space to find a suitable type in a Super SO8 package. The voltage mus be limited for this amp to something like max +-55V, as the coil will only be able to handle less than 10A also to find suitable MosFets I’m sure I will have to use 150V versions and not 200V as I usually do.

PCB will be 4 layers and will be made at JLCPCB. I will try to use basic components from JLCPCB as much as possible to limit the cost, as it cost 3 USD for every extended component type you use.

the MosFet footprints will be perforated by a number of vias which will act as a thermal conductor from the topside of the PCB to the bottom side, where the heatsink will be placed.

Stay tuned for updates and progress 😉

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