Power playground project

Posted on Thursday, February 19th, 2015 in hacks by DP


Spacewrench over at Dorkbotpdx published a new build, a Power Playground project:

It’s a PMOS/NMOS H-Bridge with FETs that can handle 3 amps or so, plus a SPI current sensor, some switches & a rotary encoder (not stuffed yet), and a 7-segment display, all controlled by a Teensy-3.1 running FreeRTOS.
I made this because I’m always running into battery, power, inductor and transformer issues I don’t have any experience with. The idea is to use the H-bridge configuration and current sensors to experiment with moderate-current PWM, motor control, power-line synchronization, battery charging and discharging, etc.


This entry was posted on Thursday, February 19th, 2015 at 7:00 pm and is filed under hacks. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.

2 Responses to “Power playground project”

  1. Max says:

    H-bridges are great fun until (not if) for whatever reason the high and low side manages to turn on at the same time, however briefly…

  2. f4eru says:

    it’s nice and cute, but i don’t recommend this hbridge architecture for an experimental project.
    – using VBATT for mos gates is not a good idea : it blows up as soon as a transient exceeds 20V on VBATT
    – using a Nmos only bridge is better, with a regulated gate supply (bootstrapped for the upper ones)
    – using dead time control integrated in the mos drivers is good practice. Experimental software should not be relied on for that
    – implementing an overcurrent cutoff in HW is a good idea for avoiding the smell of burnd mosfets, especially when dealing with experimental setups.
    – don’t forget an overvoltage clamp that can handle a high power. It’s crucial when your motor goes into a generator quadrant, even more if your hbridge cannot handle an overvoltage.

Leave a Reply

Notify me of followup comments via e-mail. You can also subscribe without commenting.

Recent Comments

  • gant: They still have a couple of the more expensive (but still considerably cheap) 5S-I-S01 in stock...
  • readybrek: Anyone got a any recommendations for a budget-priced hot air station?
  • William: lol I'm happy to waste 3c for each program/debug cycle... but probably not the time spent soldering a new device down to a proto board!...
  • Joe Desbonnet: Ya, I can recommend the low melting point solder. I used brand 'ChipQuik' and it's amazingly easy to use.
  • Jerome: I need a new BusPirate for the Fablab ;) Many thanks!