FEDEVEL
Platform forum

rost. , 09-11-2024, 09:56 PM

Hi, I need a smart boi!
I want to build something with the following ic: https://www.ti.com/lit/ds/symlink/tps92201.pdf?ts=1726050778499&ref_url=https%3A%2F%2Fwww.ti.com%2Fproduct%2Fde-de%2FTPS92201 (TPS92201)

The ic needs to power 2X UV LED and therefore should limit the current and let the voltage variable.

The data sheet says the following:
7.3.5 LED Current Setting:The LED current is set by the external resistor between the FB pin and GND, calculated as...

But on 8.2.2.2 **Setting the Output Voltage** it says the following:

When sizing R2, in order to achieve low current consumption and acceptable noise sensitivity, use a maximum
of 200kΩ for R2. Larger currents through R2 improve noise sensitivity and output voltage accuracy but increase
current consumption.

Theres a schematic in the datasheet which you can see down below. I have no clue, if I can only limit the current and let the voltage variable, or have to limit both.

Thanks for your help, im new to electronics :Kads2: < 3 (Bearbeitet)

rost. , 09-11-2024, 09:59 PM

I know the screenshot of 8.2.2.2 is partially about the current consumption of the ic, but "setting voltage" and "Vout" implies that i can limit the voltage...?

SirJames , 09-12-2024, 04:40 PM

I believe that output voltage row is just for designers to understand that Vout will be equal to forward voltage of your LED (from VA characteristics) plus voltage drop on feedback resistor. You are not setting Vout. It is determined by LED and limited by Vin.

That paragraph about Setting the Output Voltage is kinda weird. It's probably from similar IC so they just paste in datasheet without any example circuit with 'R2' in it.

rost. , 09-12-2024, 06:08 PM

Thanks for your answer!