2 LED Driver Boards in a Row ?

[TorchBoy]

2 LED driver boards not so good

This works if the drivers behave as resistive. In this case, you're using linear drivers which essentially drop off any excess voltage using resistors until the proper output voltage is reached.

So both would try to drop all the volts, and may not come to rest at a happy mid point. And before they sorted themselves out to come to a balance, one or the other might burn out.

 

[TigerhawkT3]

Re: 2 LED Driver Borars in a Row ?

So LDOs work fine in series, but some drivers (such as buck or boost ones, or ones containing an inductor) may ? Is that the nutshell?

 

[J.D.]

Interesting discussion ...
Can´t wait to receive the boards to play with them.

btw kaidomain has the multimode 3xAMC7135 in stock ...

 

[rhuck60]

Re: 2 LED driver boards not so good

Quote:
Originally Posted by 2xTrinity
This works if the drivers behave as resistive. In this case, you're using linear drivers which essentially drop off any excess voltage using resistors until the proper output voltage is reached.

So both would try to drop all the volts, and may not come to rest at a happy mid point. And before they sorted themselves out to come to a balance, one or the other might burn out.

One thing to remember is that you dont have to reach the "happy midpoint".
The driver boards operate at up to 6 volts each.

So long as one board drops a minimum of 2.4 volts you are within the limits of the other driver.

I think this will allow for difference in PWM switching, if used. (meaning that they will probably not be switched on or off at the same time)

Please remember that voltage rise unloaded or fall under load is not instantaneous.

To make sure it would work, I would hookup the 2 drivers in series, one with an led connected and one without. Thats the worst case situation.

Then using a DMM measure across the plus and minus terminals of the 2 driver boards. As long as one is less than 6v and the other is more than 2.4v you should be OK.

 

[rhuck60]

Re: 2 LED driver boards not so good

double post. lots of database errors last 24 hours. Barely able to get on or reply for 24 hours now.