Building my own PCB for a flashlight. My constraints are-
LED's- 6v modules, qty 6, with 650ma of current each (4a total).
Supply voltage- 12v DC. When the cord is unplugged, the internal lithiums will give 6.5v-8.4v DC. There is a battery charger IC that will take the 12v to charge the batteries. This device needs to run without the batteries (in case they go bad or I don't have them), so I need to make the circuit work from 6v-12v.
Because of this, I was planning on running the LED's in series/parallel to need 18v. I think this is ideal because I would use this step up converter to turn anything from 6v-12v into 18v. https://www.monolithicpower.com/en/...Datasheet/lang/en/sku/MP3426/document_id/1125
Would you guys do something different? I've been designing the schematics in kiCad but until im kinda stuck on what the LED voltage should be in an ideal world. Battery life is a concern but if I get >80% efficiency I would be more than happy. If I configure the LED's for 12v I would have to isolate and switch the voltage booster off when it's running on a 12v supply... which I could do but if I run on 18v then I can simply isolate with a diode I believe.
LED's- 6v modules, qty 6, with 650ma of current each (4a total).
Supply voltage- 12v DC. When the cord is unplugged, the internal lithiums will give 6.5v-8.4v DC. There is a battery charger IC that will take the 12v to charge the batteries. This device needs to run without the batteries (in case they go bad or I don't have them), so I need to make the circuit work from 6v-12v.
Because of this, I was planning on running the LED's in series/parallel to need 18v. I think this is ideal because I would use this step up converter to turn anything from 6v-12v into 18v. https://www.monolithicpower.com/en/...Datasheet/lang/en/sku/MP3426/document_id/1125
Would you guys do something different? I've been designing the schematics in kiCad but until im kinda stuck on what the LED voltage should be in an ideal world. Battery life is a concern but if I get >80% efficiency I would be more than happy. If I configure the LED's for 12v I would have to isolate and switch the voltage booster off when it's running on a 12v supply... which I could do but if I run on 18v then I can simply isolate with a diode I believe.