[PSUBS-MAILIST] PWM LED driver for Cliff's enclosure

Sat Apr 22 02:31:02 EDT 2017

River,
also I have 20 of these on order.
http://uk.farnell.com/on-semiconductor/nsi50150adt4g/led-driver-pwm-50v-to-252-3/dp/2382343
I have a couple I have played round with. They are 350ma & you string them in parrallel
to get your output Amps.  They have a wide voltage tolerance. There is instruction on
PWM dimming on the spec sheet. As our input & output voltages aren't too far 
apart, the efficiencies may not be too bad.
Alan

Sent from my iPad

> On 22/04/2017, at 5:50 PM, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Hi River,
> just a quick word on this.
> I am getting 12 dc buck / boost constant current LED drivers with PWM dimming
> control off a rotary switch potentiometer, made up for me in China.
>  Max input voltage is I think 50V. & output is 38V with variable Amps up to 3 Amps. 
> Most Psubbers seem to have a 36V system & when fully charged that is well over 36V.
> So I would revise the maximum input voltage. A lot of electric bikes also have 36V
> systems with lithium iron batteries. That may be an application.
> I went to a different LED that is smaller round but still a Verolux. Max of 80W.
> Smaller is advantageous in lots of ways.
> You can email me on alanlindsayjames at yahoo.com if you want to discuss anything
> privately.
> Alan
> 
> 
> 
> Sent from my iPad
> 
>> On 22/04/2017, at 5:03 PM, River Dolfi via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> 
>> Hey everyone,
>> I've managed to convince a professor at the University to let me tackle developing a high power LED driver for psubs purposes for a grade. I'm just curious which features everyone would like in an LED driver. I am designing a driver for the Bridgelux Vero 29 LED array and will hopefully package it into a form factor so that all of the electronics fit into the enclosures Cliff designed and presented at the last convention. 
>> 
>> So far I plan on using a small microcontroller (probably an ATTiny for those who are interested) to generate a PWM signal that will switch a MOSFET, to control the amount of power delivered from an off the shelf constant current LED driver chip. The chip I found, the LT3478, seems to be ideal for PSUBS purposes, as it contains it's own converter that will accepts anything between 5 and 36 volts. 
>> 
>> I'm also probably going to incorporate a temperature sensor that will shut the light down if it gets too hot (running the light for too long out of the water) and killing the electronics/melting the lens. The microcontroller will accept a 0-5 volt analog signal from either a potentiometer or a PLC in order to convert that to a PWM signall to dim the lights.
>> 
>> Are there any major features that I'm missing? It seems that PWM dimming and application specific temperature control are the big ones. Curious to get input from those that are running LED rigs right now.
>> 
>> -- 
>> -River J. Dolfi
>> 
>> 412-997-2526
>> rdolfi7 at gmail.com
>> rwd5301 at psu.edu
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