一种采用跨周期调制模式的单片开关电源的设计

【作者】 毛伟；

【导师】 张波；

【作者基本信息】 电子科技大学 ， 微电子学与固体电子学， 2006， 硕士

【摘要】 单片开关电源具有高效率、高集成度、高性价比、体积小、重量轻、性能好和外围电路简单等特点。现已成为开发电源设备的首选设计方案,具有广阔的市场价值。本论文研究课题来源于国家自然科学基金重点项目单片功率系统集成电路(PSoC)的研究(编号:60436030)。论文研究了一种作为PSoC原型电路的四端单片开关电源电路,此电路采用新型的跨周期调制模式,与传统的脉宽调制模式相比,提高了轻负载下的工作效率;整体控制回路采用电流峰值控制模式。内部集成低压控制电路和耐压600V的高压LDMOS,最大输出电流可达250mA;此单片开关电源输出功率小于9W,外围拓扑结构可采用反激式结构。此开关电源电路拟采用自主设计的BCD(Bipolar、CMOS、DMOS)工艺,可在P型单晶衬底上将低压控制电路和高压LDMOS功率器件集成在同一芯片上,并预备在中电24所流片。论文着重介绍了该单片开关电源电路中部分子模块:基准源电路、电流极限比较器电路、电流极限状态机电路、前沿闭锁电路和调节电路。基准源电路采用三管能隙结构,电压、电流基准温度系数分别为18ppm/℃和36.2ppm/℃;电流极限比较器和电流极限状态机电路相结合,避免了变压器产生的音频噪声;前沿闭锁电路消除了功率LDMOS管开启时产生的误关断;调节电路在芯片封装后可对关键参数调节,提高了成品率。文章对电路原理进行详细的分析,同时运用仿真工具HSPICE对电路进行仿真并给出其仿真波形及关键参数,以验证电路设计的正确性,可行性和精确性。最终子模块的仿真都达到预定的要求。在基准源电路的设计过程中,论文采用一阶补偿带隙基准源结构,由于其忽略了双极型晶体管VBE电压中高阶项的影响,因此温度特性具有一定的局限性。针对一阶补偿带隙基准源局限性,论文介绍了带隙基准源高阶补偿原理并利用二极管反向电流与温度的指数关系对带隙基准源进行指数高阶补偿。通过搭建实际电路进行了理论分析和仿真验证。仿真结果表明采用高阶补偿后,带隙基准源的温度系数由22.8ppm/℃减小为7.8ppm/℃。但此电路受工艺影响较大,需在以后的工作中进行改进。在BCD工艺基础上,论文通过Cadence软件设计了部分子模块的版图,并在更多还原

【Abstract】 Monolithic switching power supply has many advantages, such as high efficiency, high quality with low price, small size and simple peripheral circuit etc. It has already been the preferred choice for power supply equipments.At first, the development and fundamental of monolithic switching power supply are presented in this thesis. Then a novel monolithic switching power supply circuit only with four terminals is analyzed at detail. It uses Pulse Skip Modulation and current-mode topology. Low voltage control circuits and high voltage LDMOS whose breakdown voltage is around 600V are integrated on this monolithic switching power supply chip. The limited current of high voltage LDMOS is 250mA. Output power of the whole circuit is less than 9W. Flyback topology can be applied in the switching power supply design. It is going to be fabricated in The 24th Institution of China Electronic technology company with developing BCD technology.The following sub-blocks are analyzed in this thesis: reference circuit, current-limited comparator, current-limited statemachine, leading edge circuit and trimming circuit. The reference circuit adopts bandgap structure. The temperature coefficients of voltage reference and current reference circuits are 18ppm/℃and 36.2ppm/℃respectively. The combination of current-limited comparator and current-limited statemachine reduces the noises generated by transformer. The leading edge circuit could avoid LDMOS premature shutdown. Trimming circuit could adjust the key parameters of this switching power supply chip after packaging and the product rate can be increased. The fundamentals of blocks above are analyzed in this thesis. Simulation waves and key parameters that are got with EDA tool HSPICE are presented. Finally the simulation results are fulfilled the requirement.The linear compensation bandgap reference adopted in this thesis has limited temperature stability for ignoring the influence of VBE high order items. For improving the temperature stability, a voltage reference circuit that adopts high-order compensations technology with the exponential relationship between diode reverse current and temperature is presented in this thesis. The simulation result shows that the更多还原