In many power supplies, auxiliary outputs are post-regulated with the classic 3 terminal regulators to eliminate ripple and / or get better regulation. That's what we're doing in our product, where we need a low power +/- 24V power rail for closed loop hall effect current sensors. They have a pretty tight specification for the power rails, so we use a pair of LM7824 / LM7924 3 terminal regulators to post regulate a flyback power supply output.
We have now been notified that the LM7924 is sole source and possibly that one source is at risk of obsolescence.
I can think of multiple options that would use alternative parts, but everything in the classic linear regulator family is around 45 years old, so I wonder if there is any indication of what route is least likely to disappear too. My options I've considered are:
Anyone have some insight into what is most likely to be viable in the long term?
We have now been notified that the LM7924 is sole source and possibly that one source is at risk of obsolescence.
I can think of multiple options that would use alternative parts, but everything in the classic linear regulator family is around 45 years old, so I wonder if there is any indication of what route is least likely to disappear too. My options I've considered are:
- Use a floating winding for the negative rail and use LM7824 regulators for both negative and positive
- Use LM317 / LM337 adjustable regulators
- Use LM7815/LM7915 or LM7812/LM7912 with elevated output voltage by raising the ground terminal (Some risk as some brands have lower in / out limits so the number of devices is lower)
- The above two options but only using the positive devices and floating the negative winding.
- Using something more modern, either a newer linear or go non-isolated switching regulator.
Anyone have some insight into what is most likely to be viable in the long term?
