boost driver in parallel?

[boostax]

Hi guys,

is it possible to wire two boost driver like the bb 300 and the bb 650 in parallel to reach almost 1000mA.
I want to use two NimH D-Cells as a power source.
I don´t want to use a mode driver.

thanks for your help.

 

[VidPro]

I dont Know <-- gotta say that first.

these current control devices use a sence resister to detect the current flowing through them, when you tie them together the sence resister gets tied at one end, then through the curcuits things get tied back to the battery when parelleled.
the results are then unpredictable, it sort of works, then you can notice things going badly on the driver itself. and there can still be fluxuations that already do exist being compounded.
properly mashed together it will work fine. meaning you could probably tie them and adjust a few things electrically to make it work right, or filter the cross stuff, without taking all the throbbing and sencing and different currents out of the devices that will try and do eachothers work, and "flyback" to the other one.
With 2 completly different drivers and probably 2 different sensings of the current , 2 different inductors, chances are good it would be a worse matchup than anything, things would act up pretty fast.

beings there are 1amp drivers now , , , well.

 

[boostax]

Thx vidpro.

what would be the best driver you could tell me?

It´s great to have guys like you.

thanks again.

 

[MorePower]

You can parallel 2 SHO Micropucks to get close to 1000mA to the LED.

Check the application note on page 5 of this PDF. The voltage / output curves are for the standard 350mA output Micropuck. The SHO version is a 500mA output per driver.

 

[boostax]

thanks.

I think I will try both versions. just use one driver with 1000mA
and the 2 driver version.

Anywhere else to get micro pucks than from cutter?

thanks

 

[VidPro]

http://ledsupply.com/led-drivers.php

 

[Essexman]

Two 500mA micropucks will give around 750mA to the emitter, but you could try three!

 

[boostax]

ok,
sorry for my questions all the time.

but i do not really understand why these drivers do not deliver f.e. the 500mA to the led although it is described. Is this caused by the diferent parts in it?

thanks for your help

 

[MorePower]

Two 500mA micropucks will give around 750mA to the emitter, but you could try three!

Based on some measurements I took with a single 500mA Micropuck (here), I'd think that 2 of them in parallel with a modern, low Vf LED (XPG) would push closer to 900mA.

Feeding them with 2 NiMH cells means less voltage drop than if using alkaline cells, so Vin would likely be 2.4-2.5V. At that voltage, two 500mA pucks in parallel could easily drive the LED at 900-950mA with a nice flat light output.

 

[Essexman]

Based on some measurements I took with a single 500mA Micropuck (here), I'd think that 2 of them in parallel with a modern, low Vf LED (XPG) would push closer to 900mA.

Feeding them with 2 NiMH cells means less voltage drop than if using alkaline cells, so Vin would likely be 2.4-2.5V. At that voltage, two 500mA pucks in parallel could easily drive the LED at 900-950mA with a nice flat light output.

Good point. My measurements were with a SSC P4 a a couple of years ago, Vf would have been more than 3V.

Long live the Micropuck!!

 

[boostax]

ok then I think i have to get 2 of the micro pucks.

thanks for your support.

lovecpf