低过冲电压LDO线性稳压器的设计与研究-微电子学与固体电子学专业论文.docxVIP

万方数据 万方数据 摘要 摘 要 本论文的主要内容是设计一款 LDO 低压差线性稳压器，该 LDO 电路可应用 于 5V/3V 多电压选择的接触式 IC 卡接口芯片中，为外部 IC 卡提供低过冲电压的 稳定电源。 LDO 电路的基本原理是利用负反馈电路调节输出电压，使得输出电压对电源 电压和负载电流不敏感，提高电路输出电压的稳定性。本文先研究了 LDO 的工 作原理、指标参数的优化及各指标的折中，为电路的设计提供了理论依据。在此 基础上，提出本文所设计的 LDO 电路，主要由 PMOS 调整管、带隙基准源、过 流保护模块、软启动模块、瞬态增强模块构成。通过这些模块的设计，对传统 LDO 电路进行了改进与优化，改善了传统 LDO 电路的性能。新电路具有以下几个创 新点：① 5V/3V 多电压选择模式，可根据控制信号的不同输出 5V 或者 3V 两种 电压，扩宽芯片的应用范围；② 软启动模块的设计使得输出电压在启动过程中线 性上升，降低了输出电压的过冲；③ 瞬态增强模块的设计使得新电路改善了传统 LDO 电路的负载瞬态响应性能；④ 输出电压稳定且纹波小；⑤ 5V 状态时最大 80mA 输出电流，3V 状态时最大 65mA 输出电流；⑥ 具有过流保护模块，防止 电流超过额定电流对外部 IC 卡造成的损坏。 本文的仿真库工艺均采用上华 0.5μm Bi-CMOS 工艺，使用 Hspice 仿真软件 对所设计电路各指标参数进行验证。仿真结果证明了理论分析的正确性，指标参 数满足 DATA SHEET 的设定要求，达到了预期的功能。 关键词：低压差线性稳压器，低过冲电压，负载瞬态响应，软启动 I ABSTRACT ABSTRACT The content of this thesis is to design a low dropout regulator which can be applied to an asynchronous 3V or 5V smart IC card interface. This LDO can provide stable power supply which has lower overshoot voltage. The theory of LDO is that the negative feedback regulates the output voltage of the circuit. Then the output voltage is insensitive to the power supply and the load current. The thesis discusses the theory of LDO, the optimization and trade-off of the parameters, which provides theoretical basis for circuit designing. Based on this, a new LDO circuit is proposed. The new circuit is composed by the PMOS regulator, the band-gap reference, the over-current protection module, soft-start module, the transient-enhanced module and so on. The performance of LDO circuit is improved with these modules. The innovations of the new circuit are as follows: ① According to the control signal, the new circuit applies 5V or 3V voltages modes to expand the application of the new chip. ② The soft-start module makes the output voltage increased linearly to reduce the overshoot voltage. ③ The transient-enhanced module improves the load transient response. ④ The output voltage is stable and the ripple is small. ⑤ The maximal value of output current is 80mA in 5V mode and