GLYN SUPPORT paper explains:
Power Loss Signals protect Xmore® M.2 SSDs against Power Fail
Power failure - an M.2 SSD has to be able to cope with that.
The "data in flow" has to land safely in the flash memory.
But the integrity of the SSD mapping table must also be preserved so that the SSD is recognized after a system restart and can be used again.
This is why there is a requirement for effective hardware pFail protection, especially for embedded and enterprise applications.
For this, the M.2 is equipped with additional supercaps and a circuit for detecting a pFail event. With compact form factors such as the M.2 2242, this is often not possible for space reasons. Or you want to use the largest M.2 22110 capacity available on the market and not sacrifice any NAND Flash IC space on the PCB to install the supercaps there.
For this, the power fail protection must be outsourced to the host system and an effective communication between host and M.2 must take place. This communication can now be done via the power loss signals.
Read all about Power Loss Signals for pFail Protection in the GLYN SUPPORT paper.