1. I have to connect a 3W white led light as here: http://tinyurl.com/jpj3gnu & control its intensity using a 10K potentiometer.
2. If = 0.7A
Vf min = 3.2V
Vf max = 4.0V
Input voltage range: 5.4V to 8.4V . Max current we can limit is 0.5A
I think TL4242 should work in this application.
3. Attached find a workable board which i found in a device. It is used for led dimming using 10K pot & IC is TO263-7 package. I dont know which IC is this as there is no name on it.
But I think its replacement could be TL4242.
4. I have also attached its reverse schematic. I think they have placed 10K in series with 22K which goes to REF pin. If we do thevenin equivalent at REF pin, it seems that the ckt changes voltage at REF pin, so that it sense more current at pin REF pin & created the dimmming effect.
5. Can I do the equivalent in TL4242 with below connections:
Pin1: Connected to input voltage 5.4V to 8.4V, decoupled by 0.1uF
Pin2: Dont know what do connect?
Pin3: 10K pullup to pin1
Pin4: Ground
Pin5: same ckt as in attached schemtaic. Five 1.8ohms, one 470ohm, 22K & 10k pot.
Pin6: Open
Pin7: Led connector
6. If above cannot be done, then how can we use TL4242 as dimmer using 10K pot.
7. Also I dont need automotive grade, I need low cost IC. Any IC for it?
