一种高精度LDO线性稳压器的设计

发布时间：2018-06-17 08:57

  本文选题：高精度 + 软启动　； 参考：《西安电子科技大学》2015年硕士论文

【摘要】：随着移动电子设备的发展,像手机和平板电脑在全球的普及,以及未来可穿戴设备行业的兴起,电源管理技术的地位越来越重要。由于模拟电路对于电源噪声的敏感度,需要更加纯净的供电环境。LDO作为电源管理类芯片的一员,拥有结构简单、面积小、高电源抑制比和低功耗的优点,可以适用于手机等无线移动设备,受到了越来越多的重视。而由于国内发展时间较短,市场上的高端芯片大部分都被国外的芯片垄断,因此,研发中国具有自主产权的LDO线性稳压器具有重要的意义。本文设计的芯片包括基准电路、误差放大器、功率调整管模块和反馈电阻四个主要模块,还包括一些辅助电路。在论文中介绍了LDO线性稳压器的基本结构和原理,还有LDO的关键性能指标,根据一款经典的LDO结构分析了几种性能指标之间的折衷取舍;分析了LDO环路设计稳定性的难点并且介绍了简单的频率补偿方法。最后基于华虹0.35μmBCD工艺,设计了一款高精度的可调输出电压的LDO线性稳压器,输出电压范围在0.8V~3.6V之间,还具有可编程的软启动功能,最小启动时间大约100μs,可以减少启动时的浪涌电流,使输入电源上的应力大大减小;由外部偏置电源支持,输入电压可以低至0.9V,具有极低的dropout电压和出色的瞬态响应,输入电压的压差仅为几十毫伏,无输出电容或者任意输出电容均可保证电路的稳定性;具有power good功能,可以用来有选择地指示VBIAS和VOUT的值;在过温保护电路的作用下,电路的稳定工作温度范围为-40℃至+125℃,迟滞功能也可以更好的保护芯片;限流保护电路在有超过设定电流流过时就会启动,停止芯片工作,以免芯片被过大的电流烧毁。优越的性能适合于不同类型的电源和电子设备。最后,利用Cadence spectre对电路进行仿真,无论是前仿还是后仿均证明电路设计可以达到预期的设计目标,包括0.8V的基准电压,3.8A到5.5A的电流限制,芯片关断温度大约为159℃,恢复温度大约为145℃。此外还介绍了该芯片版图设计时所需要注意的问题以及该芯片采用的封装,该芯片采用一种小型的QFN封装,最后得到了一个高度紧凑的总体解决方案尺寸。本文设计的LDO线性稳压器精度很高,功耗较低,外围电路简单,节约了成本和面积,系统对负载的调节能力很强,并且可以适用于不同的应用场景,具有很高的市场价值。
[Abstract]:With the development of mobile electronic devices, such as the popularity of mobile phones and tablets in the world, as well as the rise of wearable equipment industry in the future, the status of power management technology is becoming more and more important. Because of the sensitivity of analog circuits to power noise, a purer power supply environment. LDO is needed as a member of power management chips. It has the advantages of simple structure, small area, high power rejection ratio and low power consumption. Can be applied to mobile phones and other wireless devices, has been more and more attention. Because the domestic development time is short and the high-end chips in the market are mostly monopolized by foreign chips, it is of great significance to develop LDO linear regulators with independent property rights in China. The chip designed in this paper includes four main modules: reference circuit, error amplifier, power regulator module and feedback resistor, as well as some auxiliary circuits. In this paper, the basic structure and principle of LDO voltage regulator and the key performance index of LDO are introduced. According to a classical LDO structure, the tradeoff between several performance indexes is analyzed. The design stability of LDO loop is analyzed and a simple frequency compensation method is introduced. Finally, based on Huahong 0.35 渭 m BCD process, a high precision LDO linear voltage regulator with adjustable output voltage is designed. The output voltage range is between 0.8 V and 3.6 V, and it also has programmable soft-start function. The minimum start-up time is about 100 渭 s, which can reduce the surge current and reduce the stress on the input power supply greatly. Supported by the external bias power supply, the input voltage can be as low as 0.9 V, with extremely low dropout voltage and excellent transient response. The voltage difference of input voltage is only tens of millivolts, no output capacitance or arbitrary output capacitance can guarantee the stability of the circuit; it has the function of power good, which can be used to indicate the value of VBIAS and VOUT selectively. The stable working temperature range of the circuit is -40 鈩，

本文编号：2030471