低电压启动的低功耗BOOST型DC-DC转换器的设计

发布时间：2018-03-22 21:18

本文选题：升压　切入点：反向电流　出处：《西安电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着各种便携式电子设备对开关电源需求的高性能化,使开关电源向满足市场需求的方向快速发展,包括启动电压更低,集成度和可靠性更高,功耗更小、外围元器件更少等。针对上述需求,本论文以低电压启动、低功耗为目标,对升压型开关电源进行研究和设计。首先,论文分析了BOOST型直流-直流转换器的原理、反馈模式、开关控制方式以及系统的功率级模型,并且根据应用需求,选择了峰值电流模式控制PWM作为该系统的控制模式;接着对系统双环路的稳定性进行了重点分析,并且针对本设计的电压环路补偿进行了设计与分析。根据应用需求,设计了系统的电特性参数及其功能模块,包括无运放带隙基准,误差放大器和BURST电压比较器,电压选择比较电路,PWM比较器,反向电流比较器以及调制模式切换模块,并且对芯片的低电压启动原理、调制模式切换的工作原理以及低功耗设计进行了详细地分析。然后给出了这些功能模块相应的电路结构,对其工作原理进行了详细的分析,基于SMIC 0.18μm标准CMOS工艺,使用Spectre软件对所设计的低功耗Boost转换器电路进行了仿真验证。仿真结果表明,该开关电源的输入电压为800mV~2.5V,系统输出范围是1.5V~3.3V,负载电流最大可达200mA,转换效率在160mA时可达93%,开关频率为1MHz。系统中的PWM比较器模块采用了共栅极结构,在低达800mV的电压下能够正常工作;系统内置的调制模式切换模块,可以根据负载情况自动在PWM和BURST两种模式进行切换,提高了轻负载时系统的性能;内置反向电流比较器有效地抑制了电流的回流现象,极大程度上减小了轻负载时芯片的功耗;系统在启动中会产生浪涌电流,为了有效地避免芯片的损坏,设计了软启动电路,该电路可使系统输出平缓地由零升高到调整值;芯片内部的过流,过温,欠压锁存等保护电路使芯片的工作更加安全,抗振铃电路有效地抑制了电磁干扰对芯片性能的影响。仿真结果说明所设计低电压启动的低功耗Boost型DC-DC转换器满足各项要求指标。
[Abstract]:With the high performance of various portable electronic devices for switching power supply, switching power supply develops rapidly to meet the market demand, including lower start-up voltage, higher integration and reliability, and lower power consumption. There are fewer peripheral components and so on. In order to meet the above requirements, this paper studies and designs the boost switching power supply aiming at low voltage start and low power consumption. Firstly, this paper analyzes the principle and feedback mode of BOOST DC-DC converter. Switching control mode and power level model of the system, and according to the application requirements, the peak current mode control PWM is selected as the control mode of the system. According to the application requirements, the electrical characteristic parameters and their functional modules of the system are designed, including the no-OPA bandgap reference, the error amplifier and the BURST voltage comparator. Voltage selection comparison circuit PWM comparator, reverse current comparator and modulation mode switching module, and the low voltage startup principle of the chip, The working principle of modulation mode switching and the design of low power consumption are analyzed in detail. Then, the corresponding circuit structure of these functional modules is given, and its working principle is analyzed in detail, based on SMIC 0.18 渭 m standard CMOS technology. The low power Boost converter circuit is simulated with Spectre software. The simulation results show that, The input voltage of the switching power supply is 800mV / t 2.5V, the output range of the system is 1.5V / 3.3V, the maximum load current can reach 200mA, the conversion efficiency can reach 93mAwhen 160mA, and the switching frequency is 1MHz. The PWM comparator module in the system adopts the common grid structure. The modulation mode switching module built in the system can automatically switch between PWM and BURST according to the load condition, which improves the performance of the system under light load. The built-in reverse current comparator effectively suppresses the reflux of the current and greatly reduces the power consumption of the chip when the load is light. In order to avoid the damage of the chip, a soft start circuit is designed. The circuit can make the output of the system rise from zero to adjust value slowly, and the protection circuits such as over-current, over-temperature and under-voltage latch inside the chip make the work of the chip more secure. The anti-ringing circuit effectively suppresses the influence of electromagnetic interference on the chip performance. The simulation results show that the low power Boost type DC-DC converter with low voltage start-up meets the requirements.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM46

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