RRRR LEDengin with FoC, PC2

[TrypWyr]

Okay, I've been reading and re-reading so much the last two days, I'm confusing the heck out of myself.

Trying to wire up my PC2.0 with a LEDengin RRRR, deep red. I have 2 x 2 dies in series. I have one set hooked up to the PC, running at 1A (series, so no splitting the current?).

The other set will be used for FoC. Now I'm trying to figure out the resistor. (7.4-(2.85+2.85))/1 = 1.7ohm / 1.7w resistor?

BTW, I've had some trouble determining the forward voltage of these LEDengin dies. I'm assuming since the data sheet shows 11.4 Vf for the star, I simply divided by 4 to get 2.85v for each die? Since this is a single color star, the dies are identical so I've assumed an even division...

Thanks all!

Tryp

[Gucabe]

Okay, I've been reading and re-reading so much the last two days, I'm confusing the heck out of myself.

Trying to wire up my PC2.0 with a LEDengin RRRR, deep red. I have 2 x 2 dies in series. I have one set hooked up to the PC, running at 1A (series, so no splitting the current?).

The other set will be used for FoC. Now I'm trying to figure out the resistor. (7.4-(2.85+2.85))/1 = 1.7ohm / 1.7w resistor?

BTW, I've had some trouble determining the forward voltage of these LEDengin dies. I'm assuming since the data sheet shows 11.4 Vf for the star, I simply divided by 4 to get 2.85v for each die? Since this is a single color star, the dies are identical so I've assumed an even division...

Thanks all!

Tryp

For the FoC you will need a Pex (power extender board) and a 1 ohm 2 W resistor will do fine... your assumption is correct on the forward voltage, however it changes depending on the current you will be driving the led with.

I just built one just like that, but opted for full powah with the PEX instead of FoC.

[Zzan]

From the Page 4 Table 7 of the LZ4-00R100 (02/14/12) data sheet,

Forward Voltage (@ IF = 1000mA) [1]
VF
9.8
V

Notes for Table 7:
1. Forward Voltage typical value is for all four LED dice connected in series.

I am seeing 9.8v, not 11.4v, as forward voltage at 1A. Though 11.4 could still be max I would err on the side of caution.

[TrypWyr]

LZ4-00R200, actually. Bottom of page 7, 11.4v at 1000ma.

Okay, I had a feeling the 1 ohm would work. Yeah, I got the pex for it too. The wiring for full power would use the same resistor, wouldn't it?

[Gucabe]

LZ4-00R200, actually. Bottom of page 7, 11.4v at 1000ma.

Okay, I had a feeling the 1 ohm would work. Yeah, I got the pex for it too. The wiring for full power would use the same resistor, wouldn't it?

yes same resistor... i mean for FoC you could have a smaller resistor in therms of wattage, because its not constantly on.. but could potentially get hot/damaged over time...

play it safe and get the 2W

Also dont get too greedy on the main board, dont need more than 1000 or 1250 on the led setting... if you go over that the led light for some strange reason, looks dimmer. You will get plenty more runtime that way.

[TrypWyr]

Thanks Gucabe, I appreciate the assistance. I actually ran the set at 2000 (late night, forgot that series wiring doesn't require double current... lucky I didn't pop them!), it did look dimmer than it should've. That's weird that it does that.

Ah well, my personal saber is once again on hold. Sigh. It was my first design and I just didn't plan the hilt very well. I'm about to order some new parts so I will continue with it later in the week, hopefully.

Time to play with some PVC sabers for the kiddies.

[Gucabe]

Thanks Gucabe, I appreciate the assistance. I actually ran the set at 2000 (late night, forgot that series wiring doesn't require double current... lucky I didn't pop them!), it did look dimmer than it should've. That's weird that it does that.

Ah well, my personal saber is once again on hold. Sigh. It was my first design and I just didn't plan the hilt very well. I'm about to order some new parts so I will continue with it later in the week, hopefully.

Time to play with some PVC sabers for the kiddies.

Yes that happens to us all... its not easy getting everything just right on the first try. have fun with the kids hehehe.