Biography
Enrollment Date: 2011
Graduation Date：2015
Degree：M.S.
Defense Date：2015.06.03
Advisors：Liji Wu
Department：Institute of Microelectronics，Tsinghua University
Title of Dissertation/Thesis：Research and Implementation on Reliability of Automobile Tire Pressure Monitoring System SoC
Abstract:
In this thesis, the reliability for Tire Pressure Monitoring System SoC, including EMI protection and ESD protection is designed. The design is based on ASMC`s 0.35um BCD automotive technology. Automotive electronics reliability becomes increasingly significant and challenging because of the specific requirement of automotive technology and automobiles` application environment. Firstly, whole-chip ESD protection for Low Frequency Wakeup Block is designed. The innovation point of this thesis is that a series of ESD devices by 0.35um BCD automotive technology is designed independently, including devices such as SCR witch are not contained in the process database, considering ESD design is unique by a specific technology. The difficulty of the design is the higher requirement for ESD protection and temperature range by automotive technology. In this part, typical ESD devices such as diodes, ordinary SCRs, DtSCRs and NMOSs are studied and tested under DC, TLP and high-low temperature system, respectively. Then referring to the datasheets of Infineon SP30 and NXP MPXY8300 and AEC-Q100 series standards, the design of whole-chip ESD protection is expected to have the ESD protection ability of HBM 2kV. According to this spec, based on the TLP test results and the design window, a whole-chip ESD protection network is proposed which comprises 8 discharging modes. ESD protection PAD units are designed based on the chosen ESD devices and applied in Low Frequency Wakeup block of TPMS. The design is taped out by 0.35um BCD ASMC technology. HBM test results prove that the design has the ESD protection ability in HBM 2kV. ESD devices work in the temperature range of -40℃~125℃.Secondly, Electromagnetic Immunity design for LDO of TPMS Power Management Block is designed. Referring to the national standard GB/T26149-2010, Datasheet of Infineon SP30 and along with the characteristics of LDO and Li ion Battery, the design index of this study is set that the output voltage error should be no larger than 5%, which could sufficiently provide stable supply for analog and digital circuit.In this part, the electromagnetic susceptibility of typical structures of LDO that cover all input and output pins such as the voltage input pin, the current input pin and the voltage supply are studied. Correspondingly, low pass filter, Recycled Folded Cascode Operational Amplifier and Four-Transistor-Current-Mirror are applied. Thus a novel electromagnetic immunity LDO is composed taped out by ASMC 0.35um BCD automotive technology. The post simulation results show that LDO without any EMI protection suffers an output voltage offset as much as 530mV, namely 16.7%, when injected a 5nA current EMI, which exceeds the design index dramatically. The modified topology could attenuate the offset around zero in the same case. Moreover, the modified topology could also attenuate the offset caused by EMI from voltage input pin from 13.6 mV to several micro Volts. The Electromagnetic Immunity design for LDO satisfies the design index. Based on the study above, a novel Electromagnetic Immunity LDO is proposed which could attenuate effectively the output offset caused by EMI from current input pin, voltage input pin and the voltage supply.