Timeline for draw 30W @ 5v to run LED light string and Arduino from a car battery?
Current License: CC BY-SA 3.0
8 events
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| Aug 26, 2011 at 5:36 | comment | added | stevenvh | @Steve - If you take a black box look at it you can compare it with the 7805. The black box has three connections: input, ground and output. The switcher will have a few more components. | |
| Aug 25, 2011 at 20:23 | comment | added | Steve Eisner | stevenh - assuming I use one of those found in the Linear Tech search, is the circuit similar to a 7805? This is about the limit of my experience - finding some small cap values to put on either side ;) Thanks! | |
| Aug 25, 2011 at 20:14 | comment | added | Steve Eisner | 0x6d64 - thanks, clever idea, unfortunately the LPD6803 chips are encased along with each RGB triad, so I can't easily hack into a 5V out. | |
| Aug 25, 2011 at 20:14 | comment | added | Steve Eisner | Thanks for the great suggestions guys! stevenh - I assume you're right about heat but these are industrial/building signage lights so I assume the heat tolerance is OK for our use which is only occasional (art car). I might try the 7805 for Arduino only first, but I'm concerned about the variable voltage from a car battery. Your Linear Technology search link shows you know what I mean... I don't know how the lights might actually deal with a bump above 12v. | |
| Aug 25, 2011 at 14:37 | comment | added | endolith | "The lights can run off 5-12V", so just run them off 12 V directly. No switchers. | |
| Aug 25, 2011 at 13:29 | comment | added | stevenvh | @0x6d64 - As far as I can tell the LPD6803 is not a switcher, so even when controlling the lights with PWM the voltage difference between 12V and 5V has to go somewhere, in the form of heat. | |
| Aug 25, 2011 at 13:18 | comment | added | 0x6d64 | Why not connect the LPD6803 to 12V and the Arduino to a linear regulator? Another idea: A datasheet for the LPD6803 suggests that it has a 5V output (if its Vdd is 5V or greater). I'm not sure which current you can draw from that pin or it it's accessible for Steve (he talks about a LPD6803 LED, not a single chip). | |
| Aug 25, 2011 at 12:35 | history | answered | stevenvh | CC BY-SA 3.0 |