Power Good signal indicators for DC-DC Buck converters

[Krotow]

Have a power circuit made from 24V to 5V and 5V to 3.3V Buck converters where both +5V and +3.3V power is required (3.3V is required is for ESP32-S3 and communication transceivers). Quite usual nowadays. Wanted to do power sequencing right by Power Good signals (not an issue too). Also wanted to see if particular voltage is available from Power Good aspect so got the idea to put a LED indicator on PG (Power Good) pin for both converter ICs -  LMR51425SDRRR and TLV62569PDRLR. PG pins here are open drain type with LOW as fault status. So pull-up is needed which theoretically allow to connect LED between pulled up PG and GND. Where lit LED indicate existing voltage and unlit - fault/no power. However sink current for TLV62569PDRLR PG pin is only 1 mA and that certainly is too low to drive a signal led with 10-20 mA current. To avoid magic smoke, decided to power indicator LEDs directly from 5V and MOSFET switches. This approach look kinda functional (schematics are attached below). Just wanted to know are this approach will not cause other problems besides slightly increased BOM cost?

[PCB.Wiz]

Just wanted to know are this approach will not cause other problems besides slightly increased BOM cost?

That will work, but you do not need 10-20mA these days to drive LEDs.
Just find a LED that is not total rubbish, and 1-2mA will be fine. 
 

[Krotow]

We have a few large bags of 3mm diameter LEDs in office left from previous projects. Not the newest models so certainly will draw more than 1mA.

[PCB.Wiz]

We have a few large bags of 3mm diameter LEDs in office left from previous BBprojects. Not the newest models so certainly will draw more than 1mA.

Sure, if that is how you manage BOMs and parts counts, by all means add more parts to use old stock 

[Someone]

We have a few large bags of 3mm diameter LEDs in office left from previous BBprojects. Not the newest models so certainly will draw more than 1mA.

How are you so sure 1mA is not enough current? What level of illumination is needed from a PCB level power good indicator? 20 years ago some LEDs were already low enough leakage and high enough efficiency to only need sub mA drive for indicators. Current LEDs span around 1000x or more intensity between "efficient" and "not efficient".

[Krotow]

Yeah, yeah... The PCB is a prototype and I will test the possibility to drive LEDs only by PG signal and pull-up anyway when DC converter ICs arrive. Just want to have prepared backup pads and traces for MOSFET contraption already in place in case if LEDs can't be driven directly like that.

Maybe smart guys above can throw an idea how to drive a input voltage (12V or 24V in random possibility) presence LED with minimal component count and keep the same brightness? A single resistor (SMD 0603) end with a very dimly lit LED or resistor itself warm up to +40..50C degrees. Of course there are constant current drivers for LEDs like NCR402U, NCR402T, BCR402R etc. But these will be another overkill plus take more board space than single resistor.

Sure, if that is how you manage BOMs and parts counts, by all means add more parts to use old stock 

What is wrong with reusing the old stock for prototyping? We don't want to simply throw them out and make more e-waste.

[xvr]

MOSFETs will light LEDs when its gate will be at 0 (i.e. when 'power NOT good')
You should use N channel MOSFETs and change LED and MOSFET connection

[Krotow]

MOSFETs will light LEDs when its gate will be at 0 (i.e. when 'power NOT good')
You should use N channel MOSFETs and change LED and MOSFET connection

Yep, noticed that and replaced MOSFETs to N-channel type.