PT-121 Testing

I have been testing out the Performance of the Green PT-121 Module.

This Module is rated at 3600 Lumens at 30 Amps.

I couldn't find any Drivers around that will supply 30 amps regulated. So I decided on a Constant Voltage Switching Regulator. It is adjustable up to 5.5 Volts and capable of supplying up to 50 Amps. Just fine for 30 Amps. Quite Expensive though.

I have mounted the Module to an AMD K7 CPU Heatsink and Fan.



Because this is a 150 Watt Green LED their is not much chance of using it in a Host. So it's mounted on top of a small plastic case with the Driver inside.



The Inside of the Box. I made the PCB to hold the Regulator Board. It also holds the 2 Capacitors required by the Regulator board. The Shunts I use to measure the current into the LED. It also has a second Shunt. I was going to use a Peltier untill I realised I needed a 150 Watt Paltier. That would have been too much current to drive. It also holds the 25 Turn Pot's. One adjusts the voltage to the LED Module and other Calibrates the Current Meter. Their is a small 40mm Fan drawing air across the Regulator board. At 30 Amps it is loosing about 11 Watts in heat. So it gets very hot.



With 30 Amps in the LED module it is drawing 13.2 Amps from a 12 Volt Lab Power Supply.



Currently their is no Reflector or Lense mounted. The Beam output is almost a 180 degree radiation from the module. It just spreads light all over the place in front of the Module.

This is just a simple shot inside my kitchen showing how much Green light is spread around. This is a Daytime Shot.



I have tried many reflectors and have decided on using a Reflector from a Dolphin torch. One that uses a 6 Volt Lantern Battery. I have used Silicon to mount it on the Heatsink. It's now Drying.

I can't use any of the standard LED Reflectors. Their is so much heat they just Melt.

I will post some Beam Shots once its dry.


An Amazing amount of light. I have run it at 30 Amps for well over an hour and it's been very stable. Using Constant Voltage mode the LED Current does rise a bit as it heats up. So the current needs to be set after it's warmed up. This Regulator module does have a tracking input so I may be able to use an OP-AMP and make a proper current Regulator from this module.

Not much use for such a module other than to see whats around in the way of very bright Green LED's.

I also have a Blue one rated at 30 amps. I havn't tried that one yet.


Charles

Nice set up!

You might like a reflector from one of these type of lights shown in this thread: (it's a thin metal reflector)
100W HID Mod, Est 8000 Lumen, Est Price: Just over $200.00 USD

Wonderful project! +1

Where can I purchase one of those 50A capable power supply boards? I have a project that I've been looking for something very similar for.

Wow great job! +1 :beer:

jayrob said:

Nice set up!

You might like a reflector from one of these type of lights shown in this thread: (it's a thin metal reflector)
100W HID Mod, Est 8000 Lumen, Est Price: Just over $200.00 USD

Click to expand...

Thanks for the tip.

My local Electronics store does sell a 5 Million candle power torch. Not sure if it's a Metal reflector though. The Problem with the Reflector was getting it to focus. Some very carefull cutting off the bottom of the reflector untill it focused. Focusing a LED is much differant to Focusing a Bulb. The Light output from the LED is below the bottom of the reflector when it's focused. Unlike a bulb which is above the bottom.

They also sell a 35 Watt HID Rechargable Torch for $69. Rated at 30 Million Candle Power. I might have to get it and install a brighter bulb and ballast.



Charles

rhd said:

Wonderful project! +1

Where can I purchase one of those 50A capable power supply boards? I have a project that I've been looking for something very similar for.

Click to expand...

PTH12040WAD Texas Instruments Power Management Modules

You would probably need to make a PCB to mount the regulator and Caps like I did. Their are quite a few Power Supply pins to connect to. I made the tracks on the PCB 0.25 Inch for 30 amps. Probably only just big enough.


Charles

Nice Project , are you running at the 50% duty cycle when driving at 30 amps ? , as the leds max current is 18 amps CW .

Mosc007 said:

PTH12040WAD Texas Instruments Power Management Modules

You would probably need to make a PCB to mount the regulator and Caps like I did. Their are quite a few Power Supply pins to connect to. I made the tracks on the PCB 0.25 Inch for 30 amps. Probably only just big enough.


Charles

Click to expand...

At $70+, that is not inexpensive!

Is that the kind of deal where the $70 module is like an evaluation board, and the ICs + components can be purchased on their own? Or is that $70 product THE product they're selling?

rhd said:

At $70+, that is not inexpensive!

Is that the kind of deal where the $70 module is like an evaluation board, and the ICs + components can be purchased on their own? Or is that $70 product THE product they're selling?

Click to expand...

That is for the complete module ready to use. It looks like it's made as a Drop in Regulator for larger projects.

The only other components needed is the 2 External Caps. Must be Low ESR type. And a 25 Turn pot to adjust the output or fixed resistor.



Charles

ionlaser555 said:

Nice Project , are you running at the 50% duty cycle when driving at 30 amps ? , as the leds max current is 18 amps CW .

Click to expand...

I am running it at 30 amps CW.

So far no problems at all. With that Heatsink I used I can still touch the front of the Module's PCB. The Front of the Glass on the LED is very hot though. I have run it for over 10 mins continious at 30 Amps CW without turning it off.

I have also run it up to 35 Amps CW.

LED's are much more forgiving than Laser Diodes.


Charles

Awesome work.:gj:

The wiring looks very clean. To bad the TEC did not work out but that heatsink looks more than sufficient with the fan.:beer:

rhd said:

At $70+, that is not inexpensive!

Is that the kind of deal where the $70 module is like an evaluation board, and the ICs + components can be purchased on their own? Or is that $70 product THE product they're selling?

Click to expand...

I got about 3 of them as free samples at one time. You ought to be able to do the same.

DTR said:

Awesome work.:gj:

The wiring looks very clean. To bad the TEC did not work out but that heatsink looks more than sufficient with the fan.:beer:

Click to expand...

That was actually the second Build. The First one was not so neat

That is 32 Amp Silicon cable too. Pretty big cable to work with.

I did really want to use a Peltier running it at 30 Amps CW. But a 150 Watt Peltier would have doubled the current from the 12 Volt supply.


Charles

I knew the Tracking Pin on this Regulator board should be able to turn this Constant Voltage Regulator into a Constant Current regulator.

I have now added a Small PCB with a Dual OP-AMP acting as a Current Regulator. It uses the Shunt as the Current Feedback and a precision 5 volt referance and 25 Turn Pot to set the current. The Output of the Error Amp is now feeding into the Tracking pin and adjusting the output voltage to regulate the current. It's working perfectly. I can now control the Current from 0 up to 50 amps. But of course I dont go over 35 Amps with this LED. The Current is now %100 Stable from Cold to Hot. But I do see the Current from the 12 Volt Lab supply drop as the LED heats up. The LED current stays constant.




I have done some Beam shots with the Reflector Mounted. This was just some quick indoor shots as it too late to go outside. Also it's a bit Cold.

This one is about 6 feet to the Wall.





This would be about 20 Feet.




I will do some outdoor shots when I get a chance. The Reflector I ended up using is looking good.

I also need to make a new Single PCB and include the Current Regulator on the same Board as the rest of it. This was just a quick test to make sure the Tracking pin would work as a current control pin.


Charles

Interesting, I thought the track pin only controlled the ramp up/down and was useless while it was running. I have one of these little modules, I'd be interested in a schematic on how you did the current control with it.

You can sample them from TI also, but you need to select the "WAH" model. The WAD is not sampleable, but it's practically the same thing. You can only sample 1 now.

The Tracking pin is active all the time. You can use it to follow another power supply if needed. It's an Anlogue input. Not Digital. Whatever voltage you put on this pin is reflected at the output. Up to the Max set output of Course.

I will draw up the circuit I designed to control the current. Pretty simple. Their is a small offset in the Diff Input Amp from the shunt as I only used 5% resistors. It doesn't effect the accuray though.


Charles