Base MCU/Driver modular building block

I had Japanese today, and was fascinated by how the Bento Box was arranged. That got me thinking that the same could be done for a modular BLDC controller.

On that happy food thought I designed BentoBox. I used the Cannonball footprint and designed two stackable modules, one is the capacitor buffer bank with built-in 40V / ESD protection, the second is the actual MCU/Driver base module (the Bento Box itself).

Size is 35mm X 35mm.

Main ingredients are STM32F103 / SLM7888 driver (both in stock).

You stack the capacitor bank (which I called Uni) on top and then stack the Cannonball (I may change the name to something Shushi related later, like SpicyTuna).

On top of the MCU portion would be stacked a comm portion with UART, CANBus, etc.

I’m finishing up with a delicious real bento box picture.



I redesigned the BentoBox as part of a different effort to test power supplies and a driver for a discrete board.

In production.


Parts arrived. I’m very busy these days, not clear when can I test thoroughly.

  1. MCU works. I replaced the STM with GD, so far working.
  2. 12V buck DC-DC step down works.
  3. 3.3V buck DC-DC step down works.
  4. Driver works, tested only low side, high side needs MOSFET connected to charge the bootstrap circuit. Apparently this driver cannot use the external power to charge the high side bootstrap, it needs diodes.

Will fully assemble and load test everything when I get the time, but this is extremely encouraging. Virgin design working out of the box is rare.


I soldered external diodes to test, so this driver MUST have external bootstrap diodes AND mosfets connected to work. No wonder its so cheap. That’s like the Zastava Yugo of the mosfet drivers. BTW this Sillumin driver is the same as the Fortior and the EG diver, they all look and behave the same and have the same footprint.

I will design a diode-boosted version and see if I could open the design. These days with the war against Ukraine, I don’t want to unwittingly contribute to someone using these designs for nefarious purposes. Perhaps whoever needs the design could PM me directly.