Laser diode driver ...

things said:

hey guys, i got a high powered red laser diode, that requires around 3V @ ~220ma. Now what I was wondering, is if anyone had any idea's on a driver that could power the diode, but also support analog modulation. The modulation signal would be 0-5V, and i'd need the lasers power to adjust accordingly. ie, if I sent the laser driver's modulation input 5V, the laser would be full on, and if it got 0v, it would be right off, and everything inbetween.

EDIT: It would be good if it could run off 5V DC, and the modulation has to be somewhat fast.

Any idea's?

Thanks

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Externet said:

There is specialized circuits to drive lasers, but a simple way to run that one from 5V would be to use a not-less-than 10 Ω resistor in series to limit the current.

To modulate it from full-on to full-off range in the entire 5 Volts, a medium power transistor also added in series should handle the task.

+5V---------10Ω-----------A--|>|--K----------C--tr--E----------Gnd

Miguel

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