| ??? 04/02/10 15:05 Read: times |
#174779 - Yes, but... Responding to: ???'s previous message |
...you need a rather high supply voltage to keep the current sufficiently "constant". And you will waste "some" amount of power.
If the maximum current of laserd diode is 120mA, take a 12V supply and a resistor that is >= 100R. It must withstand about 1.4W, so use a bigger one. Put a cap of about 100n...1µF in parallel to the laser diode to prevent short overvoltages. It allows the laser diode to smoothly turn-on, when "hard" connecting the supply voltage to this arrangement and is a certain protection against ESD too, when handling the laser diode. This cap should never be omitted. LAser diode drivers are usually modulated constant current sources, that are designed to prevent overvoltages at the laser diode under all circumstances, will say during power-ons and power-offs. Poorly designed drivers, on the other hand, often suffer from short glitches and similar interferences, which can result in a sudden death of laser diode. Kai Klaas |
| Topic | Author | Date |
| Can I drive a Laser diode with only a resistor? | 01/01/70 00:00 | |
| No | 01/01/70 00:00 | |
| no datasheet =( | 01/01/70 00:00 | |
| CURRENT | 01/01/70 00:00 | |
| Guessing time, again... | 01/01/70 00:00 | |
| not really | 01/01/70 00:00 | |
| leds are contant current device | 01/01/70 00:00 | |
| Ehh??? | 01/01/70 00:00 | |
| Some lasers requires pulsing | 01/01/70 00:00 | |
| ia a laser pointer actually a laser? | 01/01/70 00:00 | |
It is, usually... | 01/01/70 00:00 | |
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| Same module, another use | 01/01/70 00:00 | |
| unless ... | 01/01/70 00:00 | |
| Yes, but... | 01/01/70 00:00 | |
| never say never | 01/01/70 00:00 | |
| 100R times 100nF gives 10µsec... | 01/01/70 00:00 |