5Amp Constant Current LED Driver

[SCVJeff]

If anyone has any LED projects without on-board regulators, here's a cute 5A Constant Current/ Constant Voltage board I'm using for mine. So far I don't hear any RFI out of it, but will look on the analyzer to make sure. This module will feed a wall dimmer, then onto two LED plates installed in the bedroom ceiling fixtures that will have no series resistors at all. REASON: Too much variation on coach B+ between battery & solar/ shore. This way I can run these 9V lights at full output even if the coach batteries are depleted.

5A Constant Current LED Driver

The new LED plate:

[MEXICOWANDERER]

Haven't seen "I" slope down yet. I cheat and use a power supply and IR to set "I". When temp ramps up current setting is reduced until temp is stable.

[DrewE]

LED forward voltage for a constant current decreases as junction temperature increases. This means, of course, that for a constant voltage supply, the forward current (and hence power dissipation) increases with junction temperature.

[MrWizard]

Moved from technology corner

[SCVJeff]

LittleBill wrote:

SCVJeff wrote:


One thing never mentioned here is that the current draw from an LED WILL change upward as it warms up, and it can roll right through the max current for the device if you are running it hard. I have that problem with LEDZILLA, and resistors wont fix that either, so the second board I bought will replace the V only regulator on it.

i will say i see the exact opposite with a led array

Clicky


i have this hooked to a lab dc CV,CC PSU, after about 1 minute it starts dropping current requirements, roughly 1ma a minute, that said it is regulated as it doesn't drop regulation till about 10.5v

I did the same here and once I saw current slowly creeping up I quickly dialed the CC knob back down. No idea if there is a tendency for LED's to run away once started, but didn't want to find out either. We need a silicon engineer on the forums...

[LittleBill]

fyi i just bought this, i have another use for this with a lipo and a robot, need a cheap LVC though, any idea's?

[LittleBill]

SCVJeff wrote:


One thing never mentioned here is that the current draw from an LED WILL change upward as it warms up, and it can roll right through the max current for the device if you are running it hard. I have that problem with LEDZILLA, and resistors wont fix that either, so the second board I bought will replace the V only regulator on it.

i will say i see the exact opposite with a led array

Clicky


i have this hooked to a lab dc CV,CC PSU, after about 1 minute it starts dropping current requirements, roughly 1ma a minute, that said it is regulated as it doesn't drop regulation till about 10.5v

[SCVJeff]

wa8yxm wrote:
5 amp is a lot to push through a LED less you are designing flash bulbs..And with multi-led Panels you would need matched led's and when one burns out the rest become flash bulbs.

But I see it is also a VOLTAGE regulator.. add a simple resistor and your LED's are very happy (one per led or with 5 volts one for every two led's).

A- If you look at the picture, those are LED ARRAYS. Each ARRAY had ONE switching regulator on the backside, since removed. There is not one LED array in existance that regulates every single LED on a board.

B- Of course they are matched.. Look at the board. And the other board looks exactly like this.

C- I explained the reason for no resistive current limiting, its simply not needed since I can dial in my current at the source.

One thing never mentioned here is that the current draw from an LED WILL change upward as it warms up, and it can roll right through the max current for the device if you are running it hard. I have that problem with LEDZILLA, and resistors wont fix that either, so the second board I bought will replace the V only regulator on it.

[LittleBill]

wa8yxm wrote:
5 amp is a lot to push through a LED less you are designing flash bulbs..And with multi-led Panels you would need matched led's and when one burns out the rest become flash bulbs.

But I see it is also a VOLTAGE regulator.. add a simple resistor and your LED's are very happy (one per led or with 5 volts one for every two led's).

its a constant current regulator, no need for him to use resistors, he can adjust current via a POT.

i like that both current and voltage are regulated. might pick one up for a project i got going with lipo

[wa8yxm]

5 amp is a lot to push through a LED less you are designing flash bulbs..And with multi-led Panels you would need matched led's and when one burns out the rest become flash bulbs.

But I see it is also a VOLTAGE regulator.. add a simple resistor and your LED's are very happy (one per led or with 5 volts one for every two led's).