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PWM modulation

dden4012

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I experimented with a m140 module with driver in a 22mm heatsink. I hooked it up to a PWM box mod and saw the dimming effect I was looking for when I adjusted the potentiometer. Is this going to harm the diode or driver? I like the idea of this because the driver is setting the max current and the PWM is modulating the output to the driver. Is there a better way to influence the power going to the driver on a handheld?
 



paul1598419

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You should be fine, as long as the current is not over 1.8 amps. Many people have done this to get an adjustable output for their hand held lasers.
 

diachi

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I experimented with a m140 module with driver in a 22mm heatsink. I hooked it up to a PWM box mod and saw the dimming effect I was looking for when I adjusted the potentiometer. Is this going to harm the diode or driver? I like the idea of this because the driver is setting the max current and the PWM is modulating the output to the driver. Is there a better way to influence the power going to the driver on a handheld?


Won't damage the diode as long as the peak current isn't any higher than the maximum current for the diode and the driver output is clean, i.e. no nasty spikes when modulated.

Better way to do it IMO is use an analogue modulated driver that takes a 0-5V signal for modulation. This will control the current directly between two set points, a minimum and a maximum.
 

dden4012

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I have ordered the 8 amp blackbuck driver and once I get it I will be holding something i dont quite understand. As far as the original topic, I dont understand how the diode could get more than the 1.8 amps the driver is set for. The PWM box mod, the way I understand it, is simply a power souce that cycles on and off the available energy. Does the X-Drive buck driver also have a PWM type of output signal to the diode?
 

Benm

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Linear regulation certainly has some advantages. PWM basically switches the laser rapidly between off and maximum current. This is perfectly fine if you stick to the maximum current in the datasheet, but people thend to push their laser diodes a fair bit beyond that.

PWM drive helps with things like heat dissipation, but does not prevent catastrophic optical failure and similar issues.
 




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