Tool/software: WEBENCH® Design Tools
I am trying to figure out how the current limiting function works. I am a bit confused since the Webench design is a little different from what the datasheet says. Ultimately I would like to add a trimpot for tuning the current limit if possible. Right now the input voltage is set to 3-4.2V, output voltage 5V, and output current limit to 15A.
In the datasheet, it shows a single resistor- Rsen.
In the Webench design tool, it has an additional resistor. What is Rfilt doing? Is it supposed to be forming a voltage divider? In addition, when I change my desired output current, webench adjusts the value of Rsense. If I wanted to tune the resistance of Rsense in real life, I would need a small footprint SMD power potentiometer, which does not exist. Can Rfilt be made a potentiometer instead since not much power flows across it?
Hi Ryan,
Resistor "Rfilt" used by Webench provides an additional flexibility to user to increase the slope of the compensation ramp externally as shown in image below.
Kindly refer page 14 of datasheet for more details.
Datasheet link: http://www.ti.com/lit/ds/symlink/lm3481.pdf
We are looking for the right contact to address the query regarding Rfilt being made a potentiometer. We shall soon get back to you on the same.
Thanks and Regards,
Umayal
