为保证系统在热插拔过程中安全工作,避免因之导致系统崩溃及系统与部件的损坏,提出一种热插拔控制芯片的设计,针对热插拔过程中可能产生的浪涌电流和过流、过压等故障现象,芯片设计中设置了多重保护功能,包括自动限制启动电流,过流时切断电路以及过压时断电,长时过压触发SCR为负载提供撬棒保护等,另外,设计了低压诊断、负载电压等检测功能,由于芯片工作中涉及较高电压和较大电流,电路采用BCD工艺(bipolar,CMOS—DMOS)实现,并对系统、电路和版图进行了优化、制得的芯片面积约为2.5mm×2.0mm,可在4.5--16、5V电压范围内正常工作,12.0V电源电压下芯片功耗约为18mW,对芯片的测试结果表明,所设计的电路功能和特性已成功实现。
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.