Dell laptop PA-10 power supply for LEDs P7, Q5

[lonesouth]

PA-10 Specs
19.5v
4.62A
90watts

using the 7135 trick, I think I should be able to run 5 P7s?

3.7v * 4 p7 LEDS = 14.8 serial voltage

19.5 available voltage - 14.8 serial voltage = 4.7 available to driver

19.5 volts * 2.8A = 54.6 watts

this sounds right in my head, but that's not saying much...any thoughts?

 

[jason 77]

Re: Dell laptop PA-10 power supply for P7

PA-10 Specs
19.5v
4.62A
90watts

using the 7135 trick, I think I should be able to run 5 P7s?

3.7v * 4 p7 LEDS = 14.8 serial voltage

19.5 available voltage - 14.8 serial voltage = 4.7 available to driver

19.5 volts * 2.8A = 54.6 watts

this sounds right in my head, but that's not saying much...any thoughts?

Sounds good to me. I am using a HP laptop power supply to power the 9 warm white LED's with a buck puck in my fish tank light I made. Been going strong for almost a year now with no problems.

you can see the power supply down the light a bit.

 

[bshanahan14rulz]

Re: Dell laptop PA-10 power supply for P7

might as well, what else ya gonna do with it, power a laptop? ahahahahhahahahaha!

But yeah, I don't see anything wrong with it...

 

[lonesouth]

Re: Dell laptop PA-10 power supply for P7

lets get silly with circuit design...I think this should work...but my brain nearly explodes when i look at it.

Each Series =
7135 Driver 4V
Q5 3.7Vx4 14.8V
Total Volts = 18.8V
PS volts 19.5V
Excess volts = 19.5-18.8=.7 volts
Heat disipated by 7135 = .7 volts * 1050mA = .735 watts

Series current=1050

Total current = 4.2 Amps

is unbalanced parallel series an issue here?