Thoughts on this ebay driver

I was looking through ebay and found this:
5A Adjustable Power CC/CV Step-down Charge Module LED Driver Voltmeter Ammeter


Anyone with any thoughts or familiarity with something like this used as a driver for an LD?

Thanks,
Jmillerdoc

Sorry, that appears to be a dead link, try this
5A Adjustable Power CC CV Step Down Charge Module LED Driver Voltmeter Ammeter | eBay

Huh, looks interesting...would be cool for a homemade lab-style laser with power adjustment- have the pots and readouts right there. I am not sure I would trust it, personally, but that's just me. I tend to shy away from using cheaply mass-produced products to power something as expensive and sensitive as a laser diode.

It's probably designed to be a battery charger or bench supply. It 'could' work but I'm not too sure if it is well behaved regarding turn on/off spikes.

djQUAN said:

It's probably designed to be a battery charger or bench supply. It 'could' work but I'm not too sure if it is well behaved regarding turn on/off spikes.

Click to expand...

Spikes of what? Current, voltage? There are some fairly good and cheap inrush limiters available I suppose one could use if that is a real concern with one of these.

I went ahead and bought one considering the price. I am going to run some tests on it. I've got an older occilascope I could use to check and verify a few things on it like ripple rejection, etc. Checking for inrush "spikes" of current should be fairly easy enough too.

I have never concerned myself with things like soft starting, current inrush, ESD, and etc when building handhelds using simple LM3xx based current sources like the Mohgasm driver. To date I've never killed a diode, probably luck? I don't know why something like this would be any less accurate than a simple current souce like the Mohgasm. That's not to say it isn't, it's just saying I haven't seen the schematic, I suppose it could be.

Thanks for the input,
Jmillerdoc

Jmillerdoc said:

Spikes of what? Current, voltage?

Click to expand...

Can be both. Only way to be sure is to scope the output during turn on, turn off and fluctuating input voltage.

I bought various DC-DC converters like that from ePay and, well, they don't meet the ratings. I got 3A modules and by just drawing an amp or so, it gets very hot and burned my finger. So I guess with that one, you'd get to 2A or so max before it gets hot. It probably uses the national semiconductor simple switcher series of controller chips (as the ones I bought do).

Always check these out with a test load on the scope before using them with a laser diode. The one I tested indeed had CV and CC, but the CC did not kick in until several tens of ms after power-on. This is fine for battery charging, but it will kill a laser diode instantly.

My review of a similar device

You got the same findings as me. The CC mode (in mine) is controlled by an LM358 which is probably powered from the output which explains the CC mode not functioning at low output voltages and the current spike at turn on is probably because the CC circuit is slowed down to keep the feedback loop stable.