LDO功率管的W为什么会影响Vdropout

努力学ic的小叶

如图c）所示，为啥W增大，VDO（Vdropout）会随之变小；还有为啥VIN增大,VDO（Vdropout）会变小？

chris2013

Increasesing the device Width (for a fixed current) will decrease the Vdsat of the PMOS device thats why you get lower Vdrop, for the 2nd question Vdo= Vout -Vin , so it makes perfect sence if Vin goes up Vdo goes down

chris2013

May you share the paper or the book ?

dsjump

在相同负载条件下，w越大，过驱动电压越小，更容易工作在饱和区吧

努力学ic的小叶

chris2013 发表于 2022-3-29 21:50
Increasesing the device Width (for a fixed current) will decrease the Vdsat of the PMOS device thats ...

对于第二个问题，Vdo=vin-vout吧

peterlin2010

chris2013 发表于 2022-3-29 21:59
May you share the paper or the book ?

High Slew-Rate Push–Pull Output Amplifier for Low-Quiescent Current Low-Dropout Regulators With Transient-Response Improvement

chris2013

努力学ic的小叶 发表于 2022-3-29 22:37
对于第二个问题，Vdo=vin-vout吧

Oh Sorry I Confused a liitle, Yes you are right.

in Figure C for the same current reducing the Vsg will require higher value for Vsd remeber the square law model (Ids=0.5*Un*Cox*W/L * (Vgs-vth)^2 .(1+lamda Vds) )

I hope its clear now.