论文标题:自动升/降压50mA开关电容电荷泵的设计
论文作者
论文导师 张波,论文学位 硕士,论文专业 微电子学与固体电子学
论文单位 电子科技大学,点击次数 172,论文页数 67页File Size1601K
2006-05-01论文网 http://www.lw23.com/lunwen_1438372/
Charge Pump; Band-gap Reference; OPAMP; Thermal protect; Soft start
小型化和多功能是便携式电子产品的发展趋势,因此要求DC/DC转换器具有高效率、低静态电流、小的板级面积、小体积和低成本等特性。传统的电源管理方法是使用电感模式的DC/DC转换器,但是随着亚微米技术的发展和多层陶瓷大电容的使用,电荷泵的效率得到提高,所以电荷泵不仅在低功耗而且在较大输出电流应用中仍然得到广泛的应用。 在对电荷泵原理研究的基础上,论文采用0.5μm标准CMOS工艺设计了一种具有宽输入电压范围和多输出规格的50mA自动升/降压开关电容电荷泵DC/DC转换器。输入电压范围为2.0～5.5V,输出电压分别为5V、3.3V、3.0V、2.7V和2.5V五种规格。在满负载条件下,静态电流为1mA;在空载情况下,静态电流为60μA;在关断情况下,静态电流小于1μA。无论输入电源电压高于或者低于输出电压,输出电压都能通过自动选择降压或者升压模式保持恒定。升压和降压模式都不需要电感元件,可提供低EMI的DC/DC转换。高的开关频率允许选用小的表面陶瓷电容,可节省板级面积、降低成本和减小输出电压纹波。具有热保护和电流限制功能,保护工作在不正常条件下的负载元件和芯片。该电荷泵采用跳周期(Skip Cycles)控制模式,具有在轻负载情况下效率高的显著优点。 通过对电荷泵DC/DC转换器的基本原理和系统功能的详细分析,论文首先介绍了整体结构,然后重点介绍了作者所负责的部分子模块电路。在电荷泵基本理论中,详细分析了线性(Linear)模式、跳周期(Skip Cycles)模式和具有迟滞控制的跳周期模式;同时也介绍了电荷泵的升压/降压工作原理以及主要性能参数及其意义。在子电路中,重点介绍了带隙基准电压源、折叠式CMOS运算放大器、热保护和软启动。每一个子电路分别介绍了基本工作原理、主要参数的计算方法和仿真结果。 在电荷泵原理分析和子电路设计基础上,运用HSPICE仿真软件对整体电路的关键指标进行了仿真并给出了详细的仿真结果。整体仿真结果表明电荷泵的功能和重要性能指标均达到设计要求。
Now, more and more electronic equipments are portable and multifunctional, which make the DC/DC converters must have special properties, such as high efficiency, low quiescent current, small board space, low weight and low cost. The inductive DC/DC converter is the traditional approach for power management. But with the development of sub-micron technologies and the use of high value multi layer ceramic capacitors, the efficiency of charge pump is improved which make charge pumps are still widely used not only in light load application but also in higher output currents condition. Charge pump operation principle and a 50mA Switched-Capacitor Automatic Step-up/Step-down Charge Pump Converter with wide input supply voltage and multi output versions, which uses 0.5μm standard CMOS technology, are presented in this paper. The input supply voltage range is 2V to 5.5V and its output versions include 2.5V, 2.7V, 3V, 3.3V and 5V. The typical ground current (quiescent current) is 1mA at full load, 60μA with no load and, and less than 1μA in shutdown mode. The input supply voltage may vary above or below the output voltage and the output will remain in regulation by automatically selecting step-up or step-down operation mode. It works well for step-up or step-down without the need for inductor, providing low EMI DC/DC conversion. The high switching frequency allows the use of small surface-mount capacitors, saving board space and reducing cost. It also includes thermal protection and current limit, protecting the load and the regulator during fault conditions. The efficiency is very high, especially under low load condition, because the output voltage is regulated by skipping clock cycles as necessary. First of all, the whole chip function diagram is designed after analyzing the principle of charge pump and the system required function. And then, the sub-block circuit is designed according to the whole chip function and structure. In the charge pump principle section, the principle of linear mode and skip mode are analyzed in detail. The principle of step-up/step-down and the main parameters are also given in there. In sub-block circuit section, the typical circuits including reference, operational amplifier,thermal protection and current limit are introduced. The basic principle and main parameters of every sub-block circuit are noted and the simulation results are given at the end of each segment. Based on the charge pump principle analysis and circuit design in the beginning chapters,
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