(Excuse my English)
I'm currently designing a laser diode driver using the LM317L constant current circuit. I've 7 different laser diodes. I was able to put them in parallel by adjusting the load of every string in order to maintain the highest possible voltage and a constant current flow. The below circuit is a single driver operating multiple similar LEDs. I adapted this circuit by adding a resistor in series to operate laser diodes (to keep a constant current flow in each string). Now that you know what I'm doing, here's the feature I want to add: I wish to control the current of every string independently in order to control the brightness of the laser diodes. The output current of every string depends on R_sense: I_out = (1.25+V_sat) / R_sense. If you reduce (for example) the value of R_sense in a specific string, the current will increase and it will also affect the current in the other strings and I don't want that. Do you have any idea about how to add this feature ?
Thank you.
I'm currently designing a laser diode driver using the LM317L constant current circuit. I've 7 different laser diodes. I was able to put them in parallel by adjusting the load of every string in order to maintain the highest possible voltage and a constant current flow. The below circuit is a single driver operating multiple similar LEDs. I adapted this circuit by adding a resistor in series to operate laser diodes (to keep a constant current flow in each string). Now that you know what I'm doing, here's the feature I want to add: I wish to control the current of every string independently in order to control the brightness of the laser diodes. The output current of every string depends on R_sense: I_out = (1.25+V_sat) / R_sense. If you reduce (for example) the value of R_sense in a specific string, the current will increase and it will also affect the current in the other strings and I don't want that. Do you have any idea about how to add this feature ?
Thank you.
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