Well, this is a first. This is kind of an embarassing first, but a first nevertheless. In my two years blogging on Cool Cap Engineer, I could never get past a third update for any of my projects. A lot of the times, I cancelled a project due to the huge time commitment for a project, or the lack of knowledge on the project’s topic. With that said: here’s the 4th update for the 24V Brushed DC Motor Controller Shield project.
In my last post, I mentioned that the original 24V Brushed Motor Controller circuit needed some improving. One of the crucial improvements I mentioned was adding overvoltage and undervoltage protection circuitry. Because of the power supply protection circuitry additions, I decided to look into the LM2574: a 12V/.5A Buck Regulator IC. By using the LM2574, not only will I be able to add the protection circuitry by manipulating the on/off pin of the regulator, but its surprisingly more efficient than the 7815 linear regulator I was using.I could not emphasize how efficient this regulator is. No matter how much I loaded the regulator, it still delivered 11.92V to the load. Even when I loaded the regulator with a 24 ohm resistor, it still maintained 11.92V. Of course, the performance will change depending on huge temperature variations, but I’m assuming the final shield will be used at room temperature.
Just for the sake of curiosity, I wanted to see how the regulator performed when I loaded it with an Arduino, which typically draws 30-40ma. To my surprise I regulator delivered 11.97V to the Arduino. So I think I will use the LM2517 in the final design.
The final thing I was thinking doing for the project was implementing the MC33035 brushless motor controller on the shield. The MC33035 can not only control DC motors, but it comes with a current limit. If I have time this week, I will implement the undervoltage and overvoltage protection circuitry with the 12V Buck regulator circuit and start working on the PCB for the shield, which will control 1 motor. Once I test the shield, I will modify the shield to control 2 motors.
Well, that’s it for me this week. Feel free to post a question, comment, or concern and I will do my best to respond back to you. See you guys next week and Happy New Years!
