Introduction of Power Loss Protection Function on SSD
March 08, 2019
Power Loss Protection (PLP) is a mechanism to ensure that the data is not lost while the SSD is writing data when a sudden power failure occurs.
Power Loss Protection (PLP) is a mechanism to ensure that the data is not lost while the SSD is writing data when a sudden power failure occurs. PLP requires technical support from the controller firmware and adds capacitors on the PCBA to provide backup power to completely write the last data from the DRAM or storage cache into the NAND flash when a sudden power loss occurs.
Due to the time it takes to write the long program for NAND, sometimes when data are written into NAND, data are lost due to a sudden power loss. Most controllers offer a power protection solution to ensure that the memory device can still operate after the power is suddenly turned off.
The SSD includes controller, DRAM, and NAND Flash. This power loss protection function requires firmware support from the controller. When the controller detects that the power supply has dropped to a certain level, the controller immediately informs the host to stop sending data. Then the data in the DRAM should be written into NAND as soon as possible. Since the power supply is lost, the DRAM will not work. Therefore, it is necessary to rely on the backup power provided by the additional tantalum capacitors on the PCBA to have extra time to ensure that the data are completely written to the NAND flash.
Currently, it is necessary to ensure that all data are safely written to NAND memory in some embedded or industrial applications. Therefore, SSD memory devices with power loss protection are recommended for important military systems, medical and industrial applications.
The power loss protection design on UDinfo’s SSD products provide about 45ms to ensure that the data in the DRAM is fully protected.