**Part Number:**LM3409

**Other Parts Discussed in Thread:**TPS92641

I have a circuit with LV3409 working well. It is essentially the design from EN PIN PWM Dimming Application for 10 LEDs along with IADJ being controlled by a 12-bit DAC.

I have connected a 24V power supply and can control the current flowing through the LEDs. The question I have is around being able to programmatically compute the right IADJ value (so that a user can specify it as e.g. "300mA" and we can set it appropriately).

I've seen the formula I LED = VADJ / 5 x RSNS - Delta IL(pp)/2 in the spec sheet. However, working through the formulas indicates there's dependency on Vin/Vout as well (or perhaps just Vin), so I'm not sure what I'm trying to do is possible without the application being able to measure at least the Vin.

So basically:

- How to compute I LED for a variety of different input voltages and output LED configurations?

- Would I need to additionally measure input and/or output voltage to compute the curve?

Many thanks!