How to change the current using microproccesor

[daviddlc]

Hopefully what I'm looking for can be done.

I need to connect 8 LEDs and be able to change the current on them, we cannot use PWM due to the project characteristics or we don't want to use D/A converter, but we can use a separate IC and communicate with it using I2C or SPI.

Does anybody can give suggestions on how to do it ?

Does anybody know of any driver to change current on LEDs ?

Please comment.

 

[Siniša]

Put "led driver i2c brightness control" in google.

 

[FvM]

Also any external driver is supposed to use either PWM or DAC techniques in a more general sense.

 

[gogo2520]

Hello
Would a digital pot work?
gogo

 

[drbizzarow]

best and cheep way is use PWM

 

[daviddlc]

As you can see we cannot use PWM.

 

[kender]

David, here's a couple of questions:
- What are the desired range, resolution and repeatability of the adjustable LED current?
- What prevents you from using the D/A? Can "separate IC and communicate with it using I2C" be an I2C DAC?
- What prevents you from using PWM? Is it an EMI requirement or an optical requirement?

Put "led driver i2c brightness control" in google.

Most of the chips returned by such search would be the PWM dimmers.