Can this be used as an analog TTL controller ?

Can this be used as an analog TTL controller in a LM317 driver ?

DealExtreme: $5.30 VMA2012 2*3W Class D Audio Amplifier Module

I don't think so.

Maybe using a resistor as a driver.

How fast do you want it to switch?

magonegro said:

Can this be used as an analog TTL controller in a LM317 driver ?

DealExtreme: $5.30 VMA2012 2*3W Class D Audio Amplifier Module

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Class D works by PWM modulating the audio signal at 4 to 10 times its max frequency (i.e 80-200Khz or even more, I've used some which modulated at 600Khz). Then the modulated signal goes through a power stage (most times push-pull power mosfet configurations). Some D amplifiers require output filtering which removes harmonics outputting an audio-like signal with little to no traces of PWM modulation. Others use special modulating schemes which rely on speaker mechanics and coil impedance so you don't need an output filter.

Do you want to modulate a laser beam to carry an audio signal or anything like that? I don't actually understand what you mean with Analog TTL modulator.


A way to current-modulate laser diodes is summing the voltage drop in the sense resistor (which would provide "reference" current) with your modulating signal and inyecting the summed signal to the feedback pin. It does work with switching drivers... and you can modulate sound with high precission.

With a good output filter to remove the PWM carrier it could probably be made to work, but it is far from ideal. For modulating diodes, I'm a fan of good old linear drivers. If you use a regulated switching power supply as a source and have the voltage just high enough to give adequate overhead without burning up a ton of power in the driver, it's not even terribly inefficient, especially compared to the old gas lasers.

My modulated 1W 445 consumes about 7W of electrical input. Compare that to a 1W ion laser that might consume 30,000W input and it looks pretty good.