advice needed on this regulator design

[hearter]

I am thinking to design a voltage regulator from 3V to 1V, but I need high efficiency like LDO, anyone did LDO on 3V to 1V? regular linear regulator can do it, but efficiency is low(you lose 2V from 3V to 1V). I don't want to use DC-DC topology because it is noisy usually, this has to be low noise application.

appreciate any advice

 

[hearter]

no one comments? anything what you think

 

[karesz]

Hi,
Is your current need top secret pls?
K.

 

[IanP]

The idea that an LDO is high-efficient is false ..
It can just tolerate low voltage difference between input and output ..
Otherwise it behaves as any other linear voltage regulator ..

One of the simplest options is to drop 2V by using 3 silicone diodes connected in series, but it can be done in one-hundred-and-one different ways ..

IanP
:|

 

[hearter]

karesz

The current requirement is not top secret. please explain!

IanP,
are you kidding? 3 silicone diodes? what is that? how can you provide enough current?

 

[edwintsu]

Maybe DC-DC in series with LDO.

 

[IanP]

are you kidding? 3 silicone diodes? what is that? how can you provide enough current?

It's not a joke, have a look at the attached picture ..
If you use diodes such as 1N400X - the available current is 1A, if you need more - go for 1N540X - they are rated for 3A, still need more?
Diode are rated for hundreds/thousands of Amps, if that's what you had in mind ..


IanP
:|

 

[keith1200rs]

karesz

The current requirement is not top secret. please explain!

You still haven't given the required current.

For efficiency it must be DC-DC converter. The suggestion of also using an LDO is a good one. There are DC-DC converters around which do just that - converter to 100mV above the required voltage then drop the rest through LDO.

In my opinion diodes are rectifiers not regulators.

Keith

 

[IanP]

In my opinion diodes are . . . . . . not regulators.

Keith

Who said they're :?:

 

[ppdr123]

diodes are not the good option.its true that it will drop down the voltage but will also descipate the power leading to lower efficiency.DC-DC can be a good option.it generates noise, but it hardly affects your circuit if it is properly isolated.

 

[keith1200rs]

In my opinion diodes are . . . . . . not regulators.

Keith

Who said they're :?:

Err, I just did.

To me a "regulator" implies some sort of stability in the output voltage under load variations, source voltage variations and temperature. A diode provides none of those.

Keith.