提出了一种用于高侧开关的短路限流及保护电路。电路采用二级保护的方式,当短路检测电压不为零且低于参考电压时,限制栅源电压，对电路限流;当短路检测电压高于参考电压时,则延时一段时间后关断功率管。芯片采用0.18 μm 100 V BCD工艺流片。测试结果表明,在先工作后短路和先短路后工作两种情况下,功率管均处于正常工作状态。电路工作电压范围为4~80 V,短路延时时间约200 μs,输出最大可持续电流可达80 A。

A short circuit current limiting and protection circuit for high side switches was presented. The mode of secondary protection was adopted by the circuit. When the short circuit detection voltage was not zero and lower than the reference voltage, the grid source voltage was limited to suppress the current of the circuit. When the short circuit detection voltage was higher than the reference voltage, the power tube would be turned off after a time delay. The chip was fabricated in a 100 V 0.18 μm BCD process. The test results showed that the power transistor was in normal working state under the two conditions of working before short circuit and working after short circuit. The working voltage range of the circuit was 4~80 V, the short circuit delay time was about 200 μs, and the maximum sustainable output current could reach 80 A.