Query : LED Driver output modification

[talespin]

Hi Everyone,

I have a LED Driver/DC Voltage boost question.

Problem:
----------------
I have a LED projector that has a driver board which powers three LED's (RGB)
LED run at less than 5V(all three have different forward voltage)
LED Datasheet : https://download.luminus.com/datasheets/Luminus_PT-120_Datasheet.pdf
LED can be run at lower continuous current - 27A
Pulsed higher current.
Frequency = 240Hz and Duty Cycle = 70%

I need to replace these LED's with a different LED for higher brightness.
Normally one would use a different/New LED driver board matching the new LED's, but the LED driver board in Projector has connection to other circuits which are very complex and OEM specific. I only want to boost voltage and limit current without changing frequency and duty cycle.
Frequency and Duty cycle to be controlled by source(Driver board).


Question1:
Is it possible to convert 5V/27A-30A to 21V/8A without changing frequency and duty cycle (if LED is being pulsed rather than continuous) by taking the output (2 wire) from LED driver board and boosting the voltage and limiting current to 8A without changing the frequency and duty cycle?
I know it is possible through DC-DC boost circuits and current limiting circuit but what I am not sure is if they will change the frequency and duty cycle.

If yes, please provide general guidance on how I can achieve this.

Question2:
I need to monitor/measure the output of LED driver board, measure frequency (In this case around 240Hz) and duty cycle.
Is there any low cost solution to capture/analyze output of the LED Driver board or I need to buy Oscilloscope?

Thank you
Happy New Year

 

[KlausST]

Hi,

Is it possible to convert 5V/27A-30A to 21V/8A without changing frequency and duty cycle

How can we know?
We don´t know anything about your circuit ... what it does .. and what parameters are imortant

What we urgently need
* old LED datasheet
* new LED datasheet
* your circuit´s datasheet
* all important additional informations like timing and waveform...

I need to monitor/measure the output of LED driver board,

We don´t know why you need to do this ... what parameters you want to monitor ... what "monitor" means for you ... what resolution, accuracy, precision on which parameters you need. What "actions" need to be performed by the monitoring system...

I´ve built "simple monitoring systems" that are designed of 5 parts and simply ON/OFF a LED.
And I´ve build "advanced monitoring systems" designed with thousands of electronic components, doing synchronous sampling of several sensors, doing lots of math, all data archived and world wide presented on a web based plaform. Equipped with a unique alarm system.

"monitoring" is a keyword withtout any standard description. You need to provide this description.

Klaus

 

[BradtheRad]

Frequency = 240Hz and Duty Cycle = 70%

Is it possible to convert 5V/27A-30A to 21V/8A without changing frequency and duty cycle (if LED is being pulsed rather than continuous)

In its simplest form this is what you're asking for. Boost converter, 240 Hz, 70% duty cycle.
Screenshot shows the moment when switch is turned Off sending current to led load.

The inductor Henry value is found by experimentation.
There's still a lot that is unpredictable. It may light the led too bright or not bright enough.

The normal output diode is unneeded if the led is a suitable substitute.
This is not necessarily the optimum method.
By interleaving two or more identical systems you might use full power from your 5V supply.

Link which runs above schematic in Falstad's animated interactive simulator:

tinyurl.com/26y44n5y

 

[talespin]

Thank you both of you. Above visual helped how it works. I think I need to get a scope and see led driver output waveforms and try to understand its working first.

Are you aware of any DC boost converter circuit which will boost 2V to 21V (>200W) with voltage and current limiting so that LED doesn't burn out.
Source is 2V 30Amp
Output required - 21V 10 Amp