Does buck converter can be controlled with potentiometer?

Thread Starter

Gembrotai

Joined Jul 2, 2019
28
Hi guys. I have a plan to make an adjustable powerbank output. I'm wandering, does buck converter can be controlled with potentiometer?

The first thing why i wanna use buck converter is that thing so efficient and less hotter than linear voltage regulator(LMseries).

Or is it a way to make a good adjustable powerbank???
 

dendad

Joined Feb 20, 2016
3,811
3A buck converter.jpg
Remove the trim pot and replace it with a front panel mounted pot.
Ebay item.
Descriptions:
Input voltage: 4.5-28V
Output Voltage: 0.8-20V (adjustable)
Output current: rated current 3A(MAX).
Switching Frequency: 1MHz
Output Ripple:less than 30mV
Efficiency:96%(max)
 

Thread Starter

Gembrotai

Joined Jul 2, 2019
28
View attachment 180846
Remove the trim pot and replace it with a front panel mounted pot.
Ebay item.
Descriptions:
Input voltage: 4.5-28V
Output Voltage: 0.8-20V (adjustable)
Output current: rated current 3A(MAX).
Switching Frequency: 1MHz
Output Ripple:less than 30mV
Efficiency:96%(max)
Thanks for your help. What potentiometer that can be used? I mean the value? Sorry if i lack about this...
 

dendad

Joined Feb 20, 2016
3,811
If I remember correctly, the board is set up as 10K ohms per volt. So, the trim pot that you take off will be a 200K, giving 20V max.
So, run this buck converter odd an old 19V laptop power supply, and use a 150K linear pot so you end up with a 15V max power supply.
Or a 120K for a 12V max.
Note the pot connections. It is wired as a rheostat, that is, a 2 terminal variable resistor. So, connect the center wiper to one end of the pot, so when you turn it clockwise, it has maximum resistance. Try to have the wires between the pot and the board fairly short.
Here is one I helped a young fellow make for his electronics work.

IMAG0482.JPG IMAG0485.JPG IMAG0486.JPG IMAG0487.JPG IMAG0484.JPG IMAG0483.JPG IMAG0481.JPG
We added a cheap voltmeter and a range switch for high and low volts out as I only had a 100K pot. So it is 1.25V-10V, then 5V-15V. (I think)
All run off a laptop power brick.
 
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