i need some help to choose voltage regulator

[praba_J]

i need to design 3.3v power supply circuit with DC9-12v external input... suggest me voltage regulators for 3.3v power supply..
i am using STM32F107RC.. some useful links or circuits whatever u know share with me here..
thanks in advance..

 

[Stefanovic]

Good morning

you can simply do a "voltage divider"

 

[praba_J]

thank you stefanovic.. but if you know some voltage regulators suggest me...

 

[wp100]

Hi,

As well as voltage the other main factor is the Current the chip will take, by itself expect it will be around 10ma.
The maximum load for that chip is stated as 150ma.

You may be able to use a 100ma 3v3 regulator but if you have a lot of leds etc connected then it might be better to get a 500ma or 1A device.
These may sound very heavy curent for your needs, but the 1A devices are very popluar and probably cheapest.

As for an exact type, you need to see what your local supplier stocks for those currents, once you have selected an exact device look up its data sheet which will show you the capacitors etc needed.

 

[RetroTechie]

How much current do you need? (maximum, not for that µC alone but entire circuit to be powered)

 

[papunblg]

Good old LM317

- - - Updated - - -

http://www.ermicro.com/blog/?p=820

 

[praba_J]

thank you wp100,retrotechie and papunplg.. i need 1A for my circuit.. i find one regulator from the internet.. LD1085.. i think it is ok for me... you can also share your views about that regulator..thank you for guidance..

 

[enjunear]

There are a lot of potential devices that could do the job. One of my favorite sites is Digikey, since it has a nice parametric search tool (Newark, Allied, etc also have them). For Digikey, search for "3.3V voltage regulator". Choose the category "PMIC - Voltage Regulators - Linear (LDO) (5393 items)". From the parametric tables, select Current - Output from 1A to the maximum (10A) and click Apply Filters. You'll get somewhere around 49 pages with 25 items per page = ~1225 choices. You can narrow them down by voltage range, but I'd start by looking at your desired package, and vendors that you can easily source from your home country.

That said, the 3A LD1085 should be fine. Most Vreg's will give you highly similar functionality with minor changes in their operating ranges, features and performance specs.

 

[milind.a.kulkarni]

Hi I will like to share some points.....
In my view one need to first work out the total power budget of your project with the safety factor and scope of further expansion and input power consumption....there are two possible options in the regulator family that are extensively used -
1) use switching regulator - bit high ripple noise, higher efficiency and external component like MOSFET, inductor , this have wide range of current...
2) Use LDO - this have very less efficiency , Low ripple noise , very less external component , Not used at higher current rating like 3 amp and above generally...

Please keep this points for tread-off then one can suggest a proper regulator....

Good Luck

 

[papunblg]

Hi I will like to share some points.....
In my view one need to first work out the total power budget of your project with the safety factor and scope of further expansion and input power consumption....there are two possible options in the regulator family that are extensively used -
1) use switching regulator - bit high ripple noise, higher efficiency and external component like MOSFET, inductor , this have wide range of current...
2) Use LDO - this have very less efficiency , Low ripple noise , very less external component , Not used at higher current rating like 3 amp and above generally...

Please keep this points for tread-off then one can suggest a proper regulator....

Good Luck

I agree with the above point. Go through a power audit. Do cost benefit analysis. As the input voltage to regulator is 9-12 V Dc range, think do you really need a LDO?

 

[praba_J]

thank you enjunear and milind.a.kulkarni...