Given that I'm using the following circuit (adapted from this forum post):
Which takes a 24V (Nominal) input and converts it over to 3.3V for an input on the Raspberry Pi Compute module. I'd like to have an LED present on the board to signify that the input is on.
The issue is that I'm using the LM2676SX-3.3 to power the 3.3V, which provides a maximum of 3A, and I need to have 128 of these LEDs in the system. At the above values, each LED will consume 8.7mA of power which is 1.3A.
I'd like to power the LED from its own 3.3V source (probably another LM2676SX-3.3), but I'm not sure how to modify the above schematic to use a separate supply?
The other option is to power the LED on the 24V side, but it needs to support a voltage range from 12V to 32V as the input. I'm not concerned with a particular brightness as long as the LED is viewable.
So how can I modify this to use a separate source for D3 (considering I need to duplicate this 128 times, so low part count) or how can I run D3 off of the 24V side with a wide input range and not turn the enclosure into a small heater?