Control Digitally?

[King of Camelot]

How could I go about controlling the circuit described in this article(https://www.bit-tech.net/article/51/) digitally? The obvious solution would be a digital potentiometer instead of just a regular old pot, only problem is that I can't find an easily controlled 10k ohm digital pot that can put out high enough voltage. Any help would be appreciated.

 

[0x34]

Digital control

I think the best way to control in input voltage to that PWM is with an integrator. You could use a simple 741 circuit as an integrator with a UP & DOWN button to control the run voltage at PIN 1 to the MIC501.

If you really want to make it Digital, Maxim offers a large array of digital potentiometers, which could be easily controlled with a PIC or AVR. 8)

I'd recommend an integrator.

 

[Roff]

The MIC502 can run off 5 volts, and the control pin current is only 2.5ua max, so you could use almost any 50k digital pot in this application. See fig.7 in **broken link removed**.

 

[0x34]

Here is what I'm talking about. If you need to control it with a Microcontroller, you can directly drive the feedback capacitor through any port of your controller and do away with the toggle switch. :wink:

 

[King of Camelot]

In reply to Ron H, why a 50k digital pot instead of 10K like the pot used in the article?

 

[Roff]

In reply to Ron H, why a 50k digital pot instead of 10K like the pot used in the article?

Only because a quick perusal of Maxim's pots seemed to show a preponderance of 50k units. 10k is fine.