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Wednesday, March 25, 2015

Powersupply for the DiscoveRap

The DiscoveRap should work from 12..24V DC. There are 3 voltage/power levels on the board. We have 3.3V for the STM32 Discovery Board, 12V for the fans (hotends, case) and the unregulated power supply voltage 12..24V for the heaters (bed, hotends).

To make it most efficient i decided to use 2 switching regulators. One for the 3.3V and one for the 12V. To make life easier the 12V are only 11.3V so a buck converter instead a buck/boost can be used for it.

Both switchers use the same IC, only the component values differ a little bit depending on the output voltage and startup time. The 3.3V start a first and approx. 10ms later the 12V are ready.

Here is the schematics for both regualtors:
And here the corresponding layout:
The size is approx. 20x20mm²

Sunday, March 22, 2015

Stepper driver for the DiscoveRap

A highend ┬ÁController should have a highend stepper driver for the RepRap Printer. I decided to use a Trinamic chip. Here is the schematics for it.

It is able to dectect missing steps an the currents are progemmed via SPI, so no jumpers/potis are necessary to configure it.

And the Layout

ReDiscover RepRap with STMs F429 Discovery Board

STMs Discovery board offers a lot of computing power and a toch LCD for only 20€.
I'm trying to make a Comfort RepRap electronics based on that PCB. I'm currently working on the interface PCB for the Discovery. It will contain all RepRap related circuits.