Research And Design Of A High Precision Temperature Detecting Circuit In Single Chip Intelligent Power Drive Integrated Circuit

Single chip intelligent power drive integrated circuit?IPD?is a high and low voltage compatible integrated circuit,which is comprised of logic control circuit,fault detecting circuit,driving circuit and power switching devices etc.High integration obviously increases the power density of the whole chip and the rising temperature of the chip leads to function's degeneration and even failure of the chip,which subsequently makes the temperature detecting circuit on the chip necessary part of the IPD.Therefore,research and design of high precision temperature detecting circuit is of great importance in the IPD and the realibility of its application system environment.Firstly,not only the implementation principles and working mechanism of the IPD,but also the analysis and the realization theory on the temperature detecting technologies are given in the introduction part,and it is found that the reason for difficulty to improve linearity of temperature detecting circuit based on BJT is that high-order factor in saturation current of BJT brings out nonnegligible non-linearity error,and that the reason for difficulty to improve sensibility and linearity of temperature detecting circuit based on MOSFET is that subthreshold state of MOSFET is unstable and it varies greatly with process,which can not be directly applied to the smart power chip with high demand of temperature detecting circuit.In these thesis,combined the practical application and feature of the IPD,an optimized temperature detecting method is proposed.To be specific,BJTs are driven in saturation region with a proportional to absolute temperature?PTAT?current and an independent of absolute temperature?IOAT?current,respectively.Then,the non-linear error is eliminated by the multiple and subtraction of two base-emitter voltage V_BEPTAT and V_BEIOAT,thereby apparently improving driven the linearity of the temperature detecting voltage.Finally,a temperature detecting module of the IPD with high linearity and high sensibility is designed based on the above principle.In this thesis,the temperature detecting circuit was realized based on the CSMC 0.5?m 600V SOI process,and the layout of the temperature detecting circuit was designed,at last the layout was taped out and tested.Test results show that at supply voltage 15V,within-45?¹25?,the sensibility of the temperature detecting voltage V_TS is 10.11mV/?,the non-linearity error is about 0.187%,and the total current is less than 100?A,all the above indexes meet the design requirements.