输出电容对LDO稳定性影响分析  

Analysis of Effect of Output Capacitor on LDO Stability

作　　者：何光旭[1] 马文超[1] 王彬[1] 

机构地区：[1]中国电子科技集团公司第五十八研究所,江苏无锡214072

出　　处：《电子与封装》2017年第8期29-32,共4页Electronics & Packaging

摘　　要：由于线性调节器内部没有开关管产生的交流开关损耗,同时比开关电源具有较低的RFI干扰,因此在现代电源系统中,仍然有它的一席之地。低压降集成线性稳压器即LDO是线性调节器的一种,一般采用P-FET或者PNP作为调整管,导通压降可以小于100 m V,效率得到大大提升,在射频、无线、电池供电等领域得到广泛应用,但必须对其做环路补偿,才能稳定工作。首先讨论了内部补偿、前馈电容补偿和输出电容补偿之间的关系,然后给出如何选择输出电容,最后以某输出可调LDO为例做仿真,说明输出电容对LDO稳定性的影响。Linear regulator has no switch transistor that generates AC switch loss and thereby incurs lower RFI interference than switching power supply. Low dropout regulator（LDO） generally uses P-FET or PNP as regulated transistor to obtain 〈100 m V dropout voltage, which enables its wide application in RF, wireless and battery supply. However, LDO must be compensated to work stably. In the paper, the relationship between internal compensation, feedforward capacitor compensation and output capacitor compensation, and efficient selection of an output capacitor are discussed. The simulation result of TPS7H1101 shows the effect of output capacitor on LDO stability.

关 键 词：LDO 前馈补偿 输出电容补偿 

分 类 号：TN432[电子电信—微电子学与固体电子学]