I own a really bright led lamp that I want to dim. It is powered by a constant current power supply that can supply 37mA between 11V to 17V. If my lamp is connected the voltage settles at 13.58V.
With a bench powersupply I determined, my desired brightness is reached at 1mA where the voltage drops to approximately 12.7V. To limit the current to 1mA while still using the constant current source I've added a parallel resistor like this:
For some reason this wont work. The voltage drops to 2.7V, the current on the branch with the resistor is 7.28mA, and the current on the branch with the led lamp is immeasurably small.
Is there something I'm missing? Or is there another possibility to dim the LEDs besides PWM? I thought abouth changing the sense resistor of the power supply but I don't really want to mess with the power supply.