Abstract: To avoid the faults arising from hot board insertion,which may lead to the damage of the board and the backplane and even give rise to the collapse of the system in the worst-case scenario,a hot swap controller IC is developed to ensure the safe insertion and removal of a circuit board from a live backplane.To prevent over current/over voltage and surge current faults,multi protections for both the board and backplane,including a limit on the automatic starting current, a circuit breaker that triggers in the event of over current faults,and the driving of an SCR crowbar to protect the loads in the event of over input voltage faults,are proposed and realized.The under-voltage detecting and output voltage monitoring are also available for its use.After the optimization of the system,circuit,and layout design,the IC is realized in BCD (bipolar-CMOS-DMOS) technology,which is able to operate under a very high voltage and drive current.The chip area is about 2.5mm×2.0mm.It works normally under the range of 4.5 to 16.5V and consumes 18mW at 12.0V.The test results show that the expected functions are achieved and main features meet the requirements well.

Key words: hot swap, over-current protection, over-voltage protection, UVLO, BCD technology