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I have 8 x LZ4-00B200 (14V, 700ma operating) and 8 x LZ4-00R200(9V, 700ma operating) which I would like to wire off of one power supply.

My problem is two fold. First, how should I organize the 16 LEDs? 16 in series? 8 in series in parallel with another 8 in series? I'm not sure what is best.

Second, what driver can I use to power all 16 LEDs? I was looking at some of the LED drivers from Recom but I'm really not sure which one I need.

I successfully designed a few lights with the Recom drivers using 8 LEDs but I couldn't design one for 16. Any help would be appreciated. I actively give up votes

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  • \$\begingroup\$ Do you want to do things like dim them individually, or just have them all on/off? \$\endgroup\$ – Oli Glaser Jul 13 '12 at 6:52
  • \$\begingroup\$ It depends on your acceptance criteria for efficiency, cost $/W max, and Tj rise at full power. Can you tell me? Dimming is not a problem. also depends on what voltage bins you received for each part. Otherwise std switched current sinks are inefficient. \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Jul 13 '12 at 13:40
  • \$\begingroup\$ Include both the AC>DC power, regulator & h/w in your budget $/W and these are not 45W LED's, both Red & Blue are rated for 10W max and the Red is closer to 10.3V nom vs 9V. So you have 80W of Red and 80W of Blue max but if used in series that may be an issue with 14.2V (B) and 10.3V (R) sharing same current. THis is a thermal issue of cooling the LEDs. If you can improve cooling 1A is possible. \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Jul 13 '12 at 14:06
  • \$\begingroup\$ sorry I have a CREE LED thats 45W I didn't include in the ? \$\endgroup\$ – Mike Jul 15 '12 at 18:14
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The best thing is to make 8 strings of a 14 V LED in series with a 9 V LED.

The LT3496 can drive 3 strings at maximum 750 mA from an input voltage of 3V to 24 V. So you'll need three of those for 8 strings.

enter image description here

The application needs more components than just the common series resistor, but the latter isn't very efficient; you need a few volts drop across them to get a good regulation, so that's at least 8 x 1.5 W loss.

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  • \$\begingroup\$ Do you know of any other drivers? \$\endgroup\$ – Mike Jul 19 '12 at 11:13
  • \$\begingroup\$ @Mike - what do you want different? \$\endgroup\$ – stevenvh Jul 19 '12 at 11:15

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