SPI Based Digital POT

Here is a quick search that shows two options for you.  Do you care if it has volatile or non-volatile memory?  Check it out and see what you want.  

https://www.ti.com/data-converters/digital-potentiometer/products.html#1918=SPI& 

best forum is probably Data Converters forum:

https://e2e.ti.com/support/data-converters-group/data-converters/f/data-converters-forum 

You haven't said what current you want to draw, but I don't think you will be able to find a digital pot for this circuit. The example design uses a 50 mA LED current for a resistance of 3.8 ohms. I don't think you can find digital pots that small, much less ones that can handle 50 mA, which would cause the pot to handle 100 mW.

If you want a boost converter that is SPI based and can provide adjustability, then look at the TPS92682-Q1.  I am not sure what this application is.  How many LEDs are you supporting and what if the Vf of the LED at the given load?  What is the desired output current range?  What is Vin range? Generally speaking you use a constant current source to drive LEDs, not resistors, especially at higher currents.  

I thought you wanted to control the feedback with POT but that won't work with this part, though it might work with other parts.  You can't use a digital pot to support that high a current  through the part like Keith said.  

Need a lot more information from you before we can give you good feedback.  

-fhoude

We using IR LED. The maximum current is 50mA. So we fine tune the current range from 1 mA to 50mA with multiple range of current mode.

Vf of the LED is 3V. VCC of the LED is 3.3V.  We need SPI POT for adjusting the current. The POT should be maximum 1Kohm. But shared POT value, one is 100K and another one is 10K. But 1K is better for our application. We are using only one IR LED.

What is your input voltage range?  Why do you want to use a boost converter?  Is it only 1 LED or do you have a series of them?

A 1000 ohm pot would need 1024 steps to get anywhere close to 1 ohm, and your scaling at your 50mA point would be atrocious it would probably jump from 50 mA to 25mA.

I moved this to display lighting forum.  This forum is focused on automotive and usually higher current and channel counts.  

IF the OP ever comes back here, what they need is a programmable current source:

https://www.ti.com/lit/an/slaa867/slaa867.pdf

Hi Karthi,

Our expert is currently celebrating Chinese New Year and is out of office. He/she will reply to you after Feb.18 when he/she is back to office. Thanks for your understanding.

Best Regards,

Steven

Hi Karthi,

May I understand what is your input voltage range? Is the load only 1 LED or do you have a series of them?

Best Regards,

Steven