SparkFun Forums 

Where electronics enthusiasts find answers.

User avatar
By klickitat
#204370
I have a 2 wire 16v. power supply and want to run a large 25Kg servo requiring 6.8v.

Can I run 2 buck converters off of the power supply, one to the servo trigger board input and another to the servo itself using the signal wire from the servo to the servo trigger board? If so what grounds have to be tied together?
User avatar
By TS-Mark
#204405
Hi klickitat,

I do not see any reason why that setup would not work. Just make sure to create a common ground throughout the entire circuit by netting the ground pins/wires together with the ground of the 16V supply. If you are using the SparkFun Buck-Boost Converter you will need to use a resistor to set the custom output to 6.8V. The Hookup Guide has the equation used to calculate that value.

Otherwise, just make sure your 16V supply can provide enough current to run the servo reliably and, if it requires more than 1.5A, you will want to use a heat sink on the buck-boost IC on the SparkFun breakout. Finally, this is unlikely, but using 2 of these from a single supply might create some noise in your circuit. If it becomes unreliable, try adding some decoupling/filter capacitors to the power input for the buck-boost converters and that should smooth everything out.