【作者】 张彬；

【导师】 冯全源；

【作者基本信息】 西南交通大学 ， 微电子学与固体电子学， 2009， 硕士

【摘要】 如今便携式电子产品已经日益普及,作为保证电池续航能力重要模块的开关电源管理芯片,其性能也需要不断完善。开关电源模块体积在减小的同时,还要维持其带载能力的不变,随着开关电源的工作频率不断提高,对开关电源芯片中的重要模块带隙基准源设计也提出了更高的要求,如高电源抑制比、低温度系数等,并且由于单位面积晶体管数量的激增,功率型开关电源的热集聚问题凸显,过热保护已成为不容忽视的问题。本文在分析了开关电源的带隙基准的应用需求,在此基础上提出了DC-DC开关电源带隙基准的设计指标,从器件选型和电路结构优化等方面考虑,设计出了一种围绕Brokaw带隙核且带过温保护的电压基准源。在对结构进行深入分析的基础上,引入了带零、极点补偿的反馈结构,优化了带隙基准的频率响应,提高了整体的电源抑制比(PSRR)’性能。采用新型的分段线性补偿方法,在高低温时能对基准输出电压的温度曲线进行直接调整,避免了传统分段补偿电路放大器的引用,有效提高了温度稳定性。过温保护功能模块在过热关断点和安全开启点处灵敏度高,输出控制信号建立迅速。仿真结果表明：带隙基准电压在-40℃-125℃的工作温度范围内温度系数达到3.74ppm/℃,电源电压2.5V-5.5V时基准输出电压为1.1943V. PSRR典型情况下约为80dB。内部集成带热滞回功能的过温保护电路,过温关断温度160℃,温度降低,安全开启阈值温度140℃,关断、开启迅速,设计的迟滞裕量符合系统要求,很好地防止了热振荡现象。本文的电路在晶体管模型为UMC的0.6μm BCD工艺,采用仿真工具Hspice完成网表仿真验证,波形输出和计算,在仿真中考虑了工艺模型的影响,使仿真结果更加接近实际。仿真结构表明电路的各项性能指标和容差性能也十分好。更多还原

【Abstract】 Portable electronic products have become increasingly popular. These products are high integration, small size characteristics. As the battery capacity assurance modules, switch-modle power supplies, their performances also need to constantly improve, mainly reflected in the reduced volume of module, while maintain its carrying capacity the same. The robustness of switch-modle power supplies directly affects the performances of electronical decices. With the switch operating frequency increasing, higher requirements are demanded on the internal integrated voltage reference’s PSRR and low temperature coefficient. As a result of transistors surge in per unit areaover-temperature protection has become a problem that can not be ignored.In this paper, we analyzed a variety of factors affecting the accuracy and temperature compensation strategies. From the device selection and structural optimization considerations, we proposed a high-performance voltage reference with OTP which is based on Brokaw bandgap core.On the basis of structure analysis, we optimized bandgap reference frequency response and improved the PSRR (power supply rejection ratio) performances. High-temperature curvature compensation circuit structure is simple and effective. Used piecewise linear compensation method at high temperature can give a direct adjustment to the temperature curve of output voltage, and effectively improve the temperature stability. Over-temperature protection function has simple structure and low power dissipation. It can be widely used for modularize in power management ICs.the added pre-turn-on design makes the overheating and security turn-on point with high sensitivity and output control signals to establish quickly. The simulation results for this circuit using Hspice show that the temperature coefficient is about 3.74ppm/℃and the output reference voltage is 1.1943V over the-40℃to 125℃temperature range 2.5V-5.5V supply voltage. The typical PSRR(Power Supply Rejection Rate) is 80.0dB. The threshold temperatures of the internal integrated thermal shutdown circuit with hysteresis are 160℃when OTP shutdown and 140℃when safely turn-on. Designed hysteresis margin can prevent thermal oscillation perfectly. UMC 0.6μm BCD process is used to simulate the circuits. Simulation tool is HSPICE. Process modle infuences were consided in the simulation, making the simulation results much closer to reality.更多还原