A Kind Of Anti-reverse Connection Protection For Redundant Power Supply Key Technology Research

In order to meet people’s growing needs in all aspects,the electronic informationrelated industries from household appliances,communications and other fields are developing rapidly,especially the integrated circuit-related products and control algorithms related to the hot new energy vehicles.In order to ensure the reverse polarity or surge impact between the electronic information system,the electric drive electronic control system and the battery pack due to man-made,vibration or load dumping,etc.,it is necessary to adopt various types of anti-reverse protection.The circuit performs reverse polarity protection and surge protection,so it is of great significance to study the antireverse connection protection circuit and its key technologies.Based on this,this thesis focuses on the research on an anti-reverse-connection protection circuit for redundant power supply and its key technologies,including the principle,overall scheme,key sub-circuits and protection functions of the anti-reverseconnection protection circuit.The main work contents are as follows:1.Analyze the requirements and application scenarios of anti-reverse connection protection（two situations of load dump and reverse voltage mutation）,study the working mechanism of the anti-reverse connection protection circuit,build the block diagram of the anti-reverse connection protection circuit controller,analyze its state diagram and In the inner control loop,the dual gate drive architecture is determined as the anti-reverse connection protection circuit scheme in this thesis.2.Analyze the key sub-modules in the anti-reverse polarity protection circuit,including bandgap reference circuit,power supply and reference circuit,bias current and clock circuit,charge pump and overvoltage protection circuit,sampling circuit and dual gate drive circuit.The bandgap reference circuit,LDO circuit,and bias circuit are responsible for supplying power to the chip,and the clock and charge pump circuit are used to drive the gate of the external MOSFET.In terms of the design of the internal drive circuit,the functions of the two MOSFETs have an ideal diode function and a hot-swap function respectively.The control circuit of the MOSFET with hot-swap function is composed of a current sampling module,a foldback current limit module,an overvoltage protection module and a drive module.The main reason for using the foldback current limit is to consider that the external MOSFET has a safe operating area.When the sourcedrain voltage of the MOSFET is large,the current limit value should be small,so that the external hot-swap MOSFET can always work in the safe area.3.Use the 0.13μm BCD process of an 8-inch foundry to conduct key sub-circuits and overall simulation.During the power-on process of the circuit,when the current exceeds 30% of the maximum current limit value,the overcurrent signal FAULT is reported,and the load current is limited to the low threshold of the foldback overcurrent limit.Both the AC ripple blocking function and the reverse voltage protection function meet the functional and preset index requirements.It can be seen that under the input power of 12 V,the circuit can be used as an anti-reverse connection protection circuit for redundant power supplies,and has the functions of undervoltage,overvoltage,overcurrent,reverse voltage protection,and AC ripple blocking.