fixed voltage regulator vs adjustable voltage regulator?

[EEHobby]

fixed 5v best voltage regulator

Thank your guys very much before for giving me help on getting -5V before. I am working on a portable instrument. My power supply is +12V battery. I need both +5 and -5 power for other IC. The method your guys recommended for generating -5 is really helpful for me. However I would like to know what's the most efficient way to get a +5V from a +12V supply? Should I use an adjustable voltage regulator or a fixed voltage regulator? I have gone through a couple of voltage regulator ICs , but I am not for sure the best way.

Thanks again for the help and advice.

 

[mengghee]

lt 7805 voltage regulator

u can try switching converter such as buck converter ? or linear regulator ? such as 7805 <-- if i can recall correctly..... if you are after good efficiency.... i think switching converter is better. hope it helps

 

[E-design]

best fix voltage regulator?

There is a lot more to choosing a regulator. For battery operation you may need something with a low standby/operating current. Switching regulator always brings a noise concern. So you have to weigh up the good and bad points according to what your application requires

 

[IanP]

Should I use an adjustable voltage regulator or a fixed voltage regulator?

As far as the efficiency is concerned, I would modify your question to: linear or switching voltage regulator? Both can be fixed or adjustable ..

If you need just 5V and you don't worry about power loses then the answer would be linear, fixed voltage regulator (for example, 7805 for 1A, for smaller currents 78L05, etc) ..
If you don't like converting to much power into heat, then the answer is switching regulator, and, as you need fixed 5V, fixed switching regulator will be the best choice, for example, LM2574-5V (1A), or hundreds of others of MAX-series, or LT-series or others ..

When will you select adjustable (linear or switching) voltage regulator: if you need adjustable output voltage, or, .. if you don't have fixed IC in hand ..

Regards,
IanP

 

[mayu_wakui]

get a heat sink too. helps a lot in heat dissipation, so i recall..