Advantech SQFlash features complete power failure protection in all product SKUs, proper power failure protection mechanisms are implemented in different product series. This complete scheme is in the combination of four different functions, Power Failure Saver, Power Drop Catcher, Flush Manager and Voltage Stabilizer.
Power Failure Saver
When using flash products, unavoidable conditions may occur, such as high/low temperatures, unstable voltage and power supply, which may affect the reliability of the data. If the power suddenly goes down or surges when the machine is operating or the voltage is lower than the specification, processing data and file information could get lost, and even the memory device itself may get damaged. Therefore, in industrial applications, a stable IS and flash device is required so that the OS runs properly and within Advantech SQFlash memory devices, just such a protection system exists.
Power Drop Catcher
In some of the ruggedized environments, the power supply could have very sharp and deep drop in a short period of time. Although power could usually recover within single mini-second (< 1ms), for low power Flash storage like CFast/mSATA, it could cause device floating and unable to boot up or read/write correctly. Considering better environmental adaptability and system compatibility, SQFlash embedded power Reset IC in all series of products to hold up this kind of sudden power drop and retain SSD controller functionality.
DRAM (dynamic random-access memory) is a volatile memory with fast access time, frequently used as a temporary cache or buffer between a host controller and backend storage. In today's SSD (solid-state drive) designs, the utilization of DRAM cache (either internal or external) has become a common practice to boost overall SSD performance, especially on small file transfers. Apart from performance benefits, caching can also improve the endurance of SSDs by consolidation multiple small transfers before pushing them to NAND Flash, reducing the amount of block erase during the process. However, there is one major drawback of cache memory - it requires power to maintain the stored information in the DRAM. This raises concerns about data integrity under situations such as unstable power supply or even power failures. Thus, it is critical for SSD firmware to implement intelligent protection schemes to preserve data integrity in the event of unexpected power loss. Several new cache mechanism technologies have been implemented in the latest controller for SQFlash SATA Flash drives to better handle power-loss situations. These technologies will be introduced in the white paper.
SQFlash 900 series product line has built-in Voltage Stabilizer to ensure SSD internally can always keep stable supple to DDR chip and Flash IC even when power input is dropping below to lower limits of power input.
This white paper is elaborating every specific protection functions in SQFlash product lines. Also, the verification of power failure resistance in each of the SQFlash design/development stage will also be elaborated on in this white paper.