BBU Design

The BBU provides power when loss of the main 12V is detected and operates through a series of modes as the BBU is working to preserve system operation and data integrity. These modes are: 5 second Ride Thru, 1 second Power Shedding, 180-second fire hose dump (data backup) (FHD). These 3 modes are defined as:

Ride-Thru (5 seconds): The BBU is design to support 5 seconds (from AC fail to OK_PWR_REDUCE asserted) of the normal canister operation before the Canister needs to initiate power shedding and the FHD operation. During the 5 second, the Drive Bays could be off-line and maintain the full operation. The CPU will detect the drives are off-line and hold any pending transactions, per the software/firmware architecture.

If main power returns within this 5-seconds period, the system will allow the drives to spin-up (come back online) again, and normal operation will resume without doing the FHD cycle.

If the system fails to signal power reduction (no OK_PWR_REDUCE asserted) and the CPLD's 20-second countdown elapses, the system will enter shutdown mode without initiating the fire hose dump (FHD) backup cycle.

Power Shedding (1 second): After the above 1seconds have elapsed, the application SW will force the CPU to transition to a lower power mode and shuts down all un-necessary I/O (PCIe, etc.) traffic. It will then notify the CPLD, that it can remove power from the devices not needed during the Data Backup operation.

Data Backup (180 seconds): The application SW now has the CPU copying data from DRAM to the SSD Flash Module. It is estimated that copying 70GB to SSD may take up to 180 seconds.

• BBU power capability: Single BBU supports 562W/6s, then 325W/180S for two cycles
• Life cycle: Two (2) years shelf life + five (5) years operation
• Operating temperature range: 13℃ - 50℃ (45℃ above 1829m¹)
• Charger: Internal Bi-direction Buck-boost Charger with normal and fast charge capability
• Calibration: Self discharge (Power resistor or Bi-direction Buck-boost) for BBU calibration
• EPOW from PSU to get 1ms overlap time for BBU taking over
• Support Hot Plug in/out
• Agency: UL2054, IEC62133, UL60950, IEC 62368, CB, BSMI
• Environmental: ROHS, REACH, WEEE