Project goal
The project called for a micro LED controller which could work up to 0.7A and work on current control. Also it needed to be able to regulate the brightness of the LED based on the data signal input. Further the data signal was interleaved with the power signal and the system had to extract power and data from the same line. It needed to support upto 24V and as low as a single LED (3V)
The last requirement was to fit all of that into a tiny package.
Solution
The first step was to find a suitable IC that would work on pure current control irrespective of voltage. Once that was done, it was tested with clean PWM to ensure that it was capable of high accuracy regulation.
The separation of data and power was done with a combination of high pass and low pass filters with an opamp in between to increase the impedance between input and output.
After that it was a simple thing to power the LED controller with the system.
The next mountain was PCB design which required multiple iterations till the size constraints were finally met.
