* usually you want low voltage drop at R6 (to increase regulation range), thus reduce the value, maybe to 1V.
(in detail it depends on your expected Laser current range)
* R4 is counter-productive, it makes it impossible to get a clean current regulation. Disconnect it.
* R5 should be 1k ... maybe up to 10k.
* C3 depends on expected regulation speed. I´d say 1nF or higher, maybe up to several uF.
(It forms a low pass filter with R5. .. and ensures OPAMP output not to oscillate)
I don´t understand the potentiometer connetions at all.
* Missing signals.
* What do you want to achieve?
I recovered the diode lasers from an old application, I don't know exactly the mWatt sure below 100...
near the case I can read L96 4G5P, but I can't find the related datasheet...???
There is one common pin, one to the laser diode and one to the light monitor. If you want better control of the emitted light, use the monitor pin as the feedback signal. These diodes can run hot and their characteristics change with temperature, monitoring the light output instead of the laser current will give far better control.
The comments about rail to rail op-amps are quite correct but if you want to stay with the LM324, try putting say -5V on pin 11 so the input pin voltages are further away from ground.
I recovered the diode lasers from an old application, I don't know exactly the mWatt sure below 100...
near the case I can read L96 4G5P, but I can't find the related datasheet...???
Hi Dana
obviously I did some tests with that circuit you see and everything works correctly...
the question was if with the same digital potentiometer I could connect 9...
could you help me, to identify the right datasheet, based on the abbreviation L96 4G5P that is on the laser diode?
--- Updated ---
obviously I did some tests with that circuit you see and everything works correctly...
the question was if with the same digital potentiometer I could connect 9...
could you help me, to identify the right datasheet, based on the abbreviation L96 4G5P that is on the laser diode?
The middle pin seems to always be the common, so use a 10K
R, with a supply of 5V, and measure the circuit V across a leg to
common to establish which diode and its polarity is connected
internal to 1 or 3, the outside pin under test.
Now confirm the other diode is good, pin 1, remove all connections,
put black on 1, red on 2, common, you should see a V then showing that
diode is good.