Driver search

[kosPap]

Greetings all!

I am searching for a driver with the following characteristics. Use will be to make my own D26 module...

1. 17mm
2. Multimode
3. 6-9V input (2-3 CR123s)
4. Vf 3.7V to drive a Q5 Cree

any luck?

Also... I had no luck with the search engine while searching a thread of a particular driver sales....The guy had several and among them was something like a VX-7????????

Thanks, Kostas

 

[TorchBoy]

5 mode linear regulator http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=2958

16 mode version of the same thing http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=3214

Both are OK to 6V.

 

[MatajumotorS]

5 mode linear regulator http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=2958

16 mode version of the same thing http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=3214

Both are OK to 6V.

This board even at 5V input (1000mA aout), you will need to heatsink the AMC chips good, or they will enter protect mode and light wil start to flicker, and 6,5V is Absolute Maxinum for PIC uController.

 

[TorchBoy]

I haven't actually seen that yet with my AMC7135 chips, maybe I'm not treating them harshly enough. But OK, just use a diode or two to drop the input voltage a bit. A bit wasteful but I don't know of any inexpensive multimode buck boards, and there's been a disappointing silence from other CPFers.

Edit - from the specsheet:

The AMC7135 has internal power and thermal limiting circuitry designed to protect the device under overload
conditions. However, maximum junction temperature ratings should not be exceeded under continuous normal load
conditions. ... When power consumption is over about ... 1000mW (TO-252 package, at TA=70°C), additional heat sink is required to control the junction temperature below 120°C.

With a LED Vf of 3.7 at 1 amp, each of the three AMC7135s will be giving a third of an amp. At 5V there'll be 1.3V dropped across each chip, or 0.43W, well under the 1W figure for extra heatsinking, but even at 1W the junction temperature would only be 120°C in 70°C ambient conditions, not the 150°C where the thermal protection cuts in. Did you have yours wrapped up in thick thermal insulation when you saw it happen?

 

[kosPap]

indeed this is precisely why I bought and DID NOT use one...

 

[TorchBoy]

indeed this is precisely why I bought and DID NOT use one...

Use one what?

 

[kosPap]

The 3xAMC7135 driver

 

[TorchBoy]

So you bought it, used it, found the thermal protection shut it down? Doesn't sound right. Didn't like it getting warm? What?

 

[kosPap]

hmm you did not get it probably...

I DID NOT USE it, cos from order to receiveing it I learned about the thermal issues.l

 

[TorchBoy]

What thermal issues? No one has shown there are any thermal issues when they are used within specification. The specifications say that AMC7135 controllers don't have thermal issues up to their rated 6V. I have shown that there shouldn't be thermal issues, because there isn't enough power dissipated by them under 6V unless you wrap it in thermal insulation.

I think you probably do not get it.

But perhaps it is not the ideal board for other reasons. What other multimode drivers have you found?

 

[kosPap]

guess I will ahve to read your other post in relaxed conditions.

Some older mails in CPF told that there would be a lot heat generated from the driver when used with 6V. In effect it was implied that the rest of 6-3.6V would turn into heat!

BUt if ther are such issues that will be a BLESSING> I have found no other driver multimode and 17mm wide, so I will be droping it as soon as I start my soldering jobs....

thanks for the heads up, Kostas

 

[TorchBoy]

Perhaps I should mention the difference between "heat" and "thermal issues". These things are pretty rugged, and will cope with a lot of heat - enough heat to burn a finger in less than the time it takes to react. (Have you ever touched an LED's star heatsink after it's been on for a while at 1 amp?) The example given in the spec sheet talks about 1 watt producing a temperature of 120°C in an ambient temperature of 70°C, so they can cope with high temperatures in themselves, and operating in high temperature environments.

Worst case scenario: A full 6 volts (not, say, 5.4V under load) driving a 1 amp LED at 3.6 volts through three AMC7135s (at 350mA each) will mean each AMC7135 dissipates about 0.84 watts. So they may well get hot but they are designed to cope with the heat.

If they get too hot (at 150°C) then they automatically turn off to cool down, so they shouldn't get damaged, but they also shouldn't get hot enough for that to happen.

 

[kosPap]

first let me thank you for your time...You are almost giving private classes to me.

I have anotehr question though. Is it worth using this board with efficiency in mind? Am i gonna lose 6V-3.6V=2.4V times that 1A = 2.4 Watts from the batteries?

Thanks, Kostas

 

[TorchBoy]

Is it worth using this board with efficiency in mind?

That's the big question. They're extremely convenient, with 5 mode and 16 mode versions easily available, and extremely easy to use, but rather wasteful. I've been hoping someone would suggest a multi-mode buck board, but it hasn't happened yet.

Since no one has, as an idea you could use something like the Kennan board from KaiDomain, along with a Charo multi-position clickie switch - cycles through three on positions then off - to replace the current setting resistor on the Kennan board. Use each on position of the switch to insert a different resistor into the circuit. I'd recommend using the present resistor (0.27 ohms) to give 750mA as the high setting.

That arrangement would cope with three CR123 cells, as you were originally talking of, and give about 85% efficiency - much better than the AMC7135 boards at 6V.

 

[legtu]

unless i'm mistaken, the 7135 regulator sold at dx and kd uses a sot-89 package w/c are rated for 0.7 watts.

how about combining one of those buck drivers used in p60 LED drop-ins(the ones that works with 6v or more) and a multi-mode board? keep in mind that with this setup, your LED current is going to be limited by the 'first' driver(the buck driver).

 

[TorchBoy]

unless i'm mistaken, the 7135 regulator sold at dx and kd uses a sot-89 package w/c are rated for 0.7 watts.

Hm, true, it's a sot-89. My apologies for missing that. But the "rating" isn't a hard and fast maximum spec - it just allows for 2 to 2.25 volts to be dropped by the AMC7135 if you want to keep the thing to 120°C if the ambient temperature is 70°C.