I have a Boost converter with a constant current mode that allows me power a high power led (Vf 34, 3A). I'd like to be able to control the current potentiometer on this device with an arduino.

To do so, I was thinking I could swap out the analog potentiometer with a digital one. I looked it up, and found this page from Analog Devices about their digital potentiometers. However, I have no idea which to choose. The potentiometer I'd be replacing is a 3 terminal, Baofeng 1/4W 10K potentiometer.

I don't have much experience with DAC/ADC, so I'm not sure if this is the best way to do it. I also looked into replacing the PWM chip on the boost converter with the arduino's pwm output, but the chips are unmarked.

I also looked at using a TIP120 with the arduino's PWM to change the brightness, but I don't think this would be the best, as it might cause surges of power.

I can include actual photos of the device, but this is the device in question. I'd ideally replace the current potentiometer, as it would allow me finer control.

  • \$\begingroup\$ Where are you thinking the difficulty lies? \$\endgroup\$ – Andy aka Dec 28 '14 at 20:50
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    \$\begingroup\$ What is the voltage your pot deals with? \$\endgroup\$ – Majenko Dec 28 '14 at 21:06
  • \$\begingroup\$ @Ethan Please post the schematic of the original circuit with the manual pot. It's hardly possible to answer your question with certainty, without knowing how the manual pot is used in the original circuit. \$\endgroup\$ – Nick Alexeev Dec 28 '14 at 22:45
  • \$\begingroup\$ Be careful using digital pots, most I've seen (including the ones you linked) can't handle voltages that are outside the supply voltages, so with a 5 V supply you can't divide a 12 V rail. Hence Majenko's question. \$\endgroup\$ – Austin Jan 29 '15 at 18:20

Based on your question "How to choose", you can see that in the link you provided, there is a table. In that, the most significant parameters you need to check is the voltage and the current. Choose Isupply (max) and Vsupply (max) according to your application.

Little explanation about other parameters:

Channels: number of potentiometers in that device.

Positions: number of steps from min. to max. resistance.

Interface: This is for programming the up/down control. If your using I2C or SPI choose accordingly. You could also choose one with the up/down interface, where you need a clk, control signal and an up/down signal. You could do this using your arduino. Or, push button is the simplest, but you will have to vary it manually.

Also, click on each device to see the block diagram. You'll get a better understanding.


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