Design And Implementation Of Driving And Protection Circuits For High-Side Smart Power Switch

PIC?Power Integrated Circuit?is one of the most important basic units in analog circuits.Since its invention in the 20th century,it has been developing rapidly.The innovative design of HLV?High and Low Voltage?compatible integrated circuits have enhanced the power density in the chip.The new demands were produced by the new wave of scalable innovation,which was along with the evolution of the information industry including automotive electronics,aerospace,high-speed railway equipment s.It is of prominent significance to apply the power output with intelligent control in the power integrated circuits.The smart power switch circuit?SPIC?has complete protection functions and the capacity to run stably in severe environments.Besides,its small size,versatility,and efficiency have gained popularity for the SPIC.The paper is aimed to design a smart high-side power switch circuit in combine with protection circuits to obtain the full functionality of a high-side power switch.The design of the chip should function properly under the input voltage range of 5V²4V and the operating temperature between-40?to 150?.And the standard working state should be 12V/7A and the output resistance(R_DS?ON?)is less than 120m?.The circuit in the paper also includes functions such as under-voltage protection,over-voltage protection,over-temperature protection,and open load detection.The paper will discuss three parts mainly:the research of the key technology of the high-side intelligent power switch,the analysis of the protection circuit,its design,and simulation,and the overall study and review of the circuit by the design objectives.During operation,the voltage regulator converts the input voltage?5V²4V?into a stable5V logic voltage to power the low-voltage logic circuit inside the chip.The oscillator and the charge pump circuit are used to drive the output of the high-side power device to ensure the stability of the gate voltage during the chip operation.The boost of the charge pump forces the output power device to work at a low resistance value in a linear region.The logic control circuit integrates signals of the internal protection module,input signals,and state feedback output signals to complete the intelligentized control for the working state of the power switch and to prevent damage for the chip and even the system caused by the abnormal conditions.The paper discussed the key technology of high-side intelligent power switches,circuit principle analysis,circuit design,and simulation implementation and so on.The circuit in the paper used a 0.35?m BCD process platform.Based on the theories,the analysis and verification were performed on the submodules of the circuit and the whole circuit with Hspice simulation tools.The turn-on time of the chip is about 90?s,the turn-off time is about 30?s.The trigger for overheat protection is 150?and the hysteresis temperature is 10?.When the power voltage is between 3.5V to 5V,the circuit will switch to the undervoltage protection status.If the power exceeds 24V,it will turn to overvoltage protection.The circuit is able to respond to the abnormal output timely.All simulation results met the design specifications.