关于LDO调整管的选择

除了NMOS的压差比PMOS的大之外
谢谢各位了

http://bbs.eetop.cn/viewthread.p ... Borderby%3Ddateline
看看这本书的第42页，应该有你需要的答案。

谢谢啦,书里的确讲的很清楚

针对这本书里讲的内容,我好有一些疑问,能否给我讲一下?
书中43页提到:
Load transient. NMOS HDO enjoys better AC line regulation due to better
PSR. DC line regulation of a regulator depends on the DC open-loop gain,
which is often sufficient in design (≥ 60dB) regardless of the pass element type.
NMOS HDO is also superior in load regulation because of the source follower
configuration, which has a smaller RS (1/(gm,N +gmb,N)) before and after closeloop
feedback. Therefore, NMOS HDO regulator would experience less voltage
undershot and overshot during abrupt load current changes.
为什么NMOS HDO有一个小的RS,它的负载调整率就比PMOS LDO好?
期待helianalog 答疑

你把那本书的第3章仔细看下，
Fig.3.2有个示意图。
应该是希望Rs越小越好。

NMOS在大功率负载时需要升压电路，PMOS比较简单

相同電路架構與MOS size下
PMOS的壓差小, 能提供電流較大, PSRR較差
NMOS反之

好书，能学到很多

以前看过一点LDO，翻了一下，我觉得应该根据负载调整率的定义来分析
Load_Regulation=delta(Vout)/delta(Iout)=Ro_pass/(1+A*beta)（通常不管N,P，A*beta>60dB）结果正比于Ro_pass/(gm.n+gbm.n)

nice...

学习了

来学习下

好书。

学习了

感觉那个电源很难设计

sansen的书里说，还有稳定性的问题。因为pmos会在反馈环中多加一级，而且这一级的gm会随负载变化，所以非主极点会随负载变化。需要很大的补偿电容。
参与讨论一下~

面积 稳定性 电源电压抑制比

学习了

点个赞！

谢谢~

学习一下

我也有同样的疑问

好书，不过NMOS的LDO讲解的不够细致，哪位大神还有NMOS LDO相关资料，分享下呗

学习了。

你的回答完美地解决了我的问题，thank you~

好书。

A fully integrated pmos ldo suffers from the problem of multipole slow response, and full spectrum psr is hard to be achieved, especially when the dropout voltage is as low as 50mV, and the power PMOS has to be very large that makes it hard to achieve fast response and good stability.