Originally Posted by
VDX
... to avoid such 'irregular' behaviour and random killing of my diodes I've developed own simple current limiting drivers capable of high pulse rates (up to 2 MHz) and currents from 100mA to 10A per channel or "parallelizing" multiple channels for higher currents - they are based od high-speed OpAmps configured for current regulating and MOSFET's driving the current, what's producing some heat when driving in the amperes range.
Actually I'm busy to test a driver, my company developed new, where a DC-DC-converter acts as current regulator to reduce voltage drops and heating, but with specific (reproducible) conditions at higher currents than 7A it tends to oszillate with high current (PS gives max. 15A) spikes and some MHz oszillation rates, what gives funny results with the IR-diode I was testing ... a 9W-diode melted a plastic lens, which is rated for 25 Watts optical througput, before it went off !! ... but from 500mA to 6A it seems to work OK ...
Viktor
would you be willing to share a schematic of your drivers?
I had built a driver to run a 20 watt IR bar diode a number of years back and i had oscillation when i ran it below the design current but ran well at full output, what it did is i used a comparator with a an OpAmp that drove about 7 transistors in parallel, i no longer use it as i have a different very high current power supply with a programmable current that i use for that diode bar.
But i love to see one of yours for less output current.
as for premade drivers i am going to get a sample from the guy in Russia and the guy from Australia when i need a device for 2 diodes, i wish he made single ones.
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