Extremely low quiescent current LDO

[jutek]

hello

do you know what circuits are used in extremely low quiescent current LDO applications?

extremely low means 100nA with 1A load current !!!

what if i need fast response? it means i need high bandwidth so high amplifier current.

regards

 

[electronrancher]

Tht's right - if you need fast response it is impossible to slew the gate of the pass device up and down with 100nA. This is probably a device that changes it's bias if it is in slew - similar to the "gain boosted" or "Slew-rate enhanced" op amp.

So we cheat, and slew the gate with 2mA, but after everything has settled out - look, my Q current is only 100nA!

Although it sounds nice, it's not too practical - the wideband noise from this LDO will be way too high to use in sensitive applications, and it will be very sensitive to glitches on the power supply due to it's very faint q-current.

 

[Humungus]

Just one silly question: what's the minimum current this LDO must provide? That is, the LDO is going to supply something. So, what's the minimupm consumption of that "something"? If the LDO is supposed to switch from states in which either it supplies 1Amp and then nothing is connected to it, I think a better solution would be to put it to sleep in stand-by mode. This only has the disadvantage that, when needed, it must fully start up before being able to operate again.

 

[jutek]

Just one silly question: what's the minimum current this LDO must provide? That is, the LDO is going to supply something. So, what's the minimupm consumption of that "something"? I

the minimum current is 1mA

 

[xxf_86]

I think maybe you should know what the quiescent current really is ? It is when the LDO provide 100mA or just it wake up?

 

[drabos]

Could somebody give me information about how swith the LDO to sleep mode?

 

[derekqiao]

You can design a feedback circuit to follow the loading current. If Iload decreases, the quiesent current could be reduced too. But the transient response is damaged. You have to trade off the response speed and the quiesent current.

Regards

 

[movingbait]

LDO from maxim, FET based

Make the wheel square only when no one made it before.

**broken link removed**

MovingBait.Ü