I have a question about current regulation on a single power-source board that runs either a laser, an led, or both. See my (kinda ugly) drawing for reference.
The rotary switch has 4 modes:
Off (not shown)
1 - laser only
2 - both laser and led
3 - led only
Diodes prevent current from Mode 1 or Mode 3 from backing onto the Mode 2 paths.
Assume the target current levels are 70mA for the laser and 350 mA for the LED.
For single mode (laser or led) the DDL circuits are easy to design: just choose the sense resistor and pot that provide the current you want for that side.
My question: in the drawing, in DUAL MODE, will the DDL's still cause the target current levels to be delivered to each side, or have I completely missed something?
From a power-delivery-design standpoint, I don't know what to expect for dual mode.
I guessing that either it will work fine because each DDL will only pull what it needs to deliver its constant current level...
OR
I'm clueless, and current delivery will be totally lopsided because of some "path of least resistance" issues, or something like that.
Anybody care to shed some light on this for me. THANKS!
The rotary switch has 4 modes:
Off (not shown)
1 - laser only
2 - both laser and led
3 - led only
Diodes prevent current from Mode 1 or Mode 3 from backing onto the Mode 2 paths.
Assume the target current levels are 70mA for the laser and 350 mA for the LED.
For single mode (laser or led) the DDL circuits are easy to design: just choose the sense resistor and pot that provide the current you want for that side.
My question: in the drawing, in DUAL MODE, will the DDL's still cause the target current levels to be delivered to each side, or have I completely missed something?
From a power-delivery-design standpoint, I don't know what to expect for dual mode.
I guessing that either it will work fine because each DDL will only pull what it needs to deliver its constant current level...
OR
I'm clueless, and current delivery will be totally lopsided because of some "path of least resistance" issues, or something like that.
Anybody care to shed some light on this for me. THANKS!