Switching regulator to drop down a 12 V battery voltage to 9v and 5V

[KatyG]

Hi everybody,

I have a 12 V 7 A/Hr battery and need to drop down the voltage to both 5V and 9V to power two different devices. The total current I need is about .4 A. Which regulator would you recommend me to use? I was thinking about using switching regulators because they provide less power dissipation than linear, but I don't know how to choose one for my specs. Any information will be helpful. Thanks.

 

[Orson Cart]

A simple forward converter - buck converter - should work well for this app, since you can combine o/p inductor windings on the same core to give better regulation on the outputs when the loading changes on either output. Or have two seperate and quite simple buck converters e.g. NCP3064, https://www.onsemi.com/pub_link/Collateral/NCP3064-D.PDF

Regards, Orson Cart.

 

[cameo_2007]

Have a look at LM2676 Series of switching regulators. you should be finding what you need.

 

[KatyG]

Thanks Cart, I will look at that one. I heard that switching regulators can produce noise, I will use the output of the regulator to power up an equalizer and an amplifier, do you think that Linear regulators are better for audio applications?

---------- Post added at 16:51 ---------- Previous post was at 16:41 ----------

Thanks a lot for the recommendation, Cameo. I will take that regulator in consideration for my design since I really like its specs.

 

[Orson Cart]

Usually linear is better - post filtering of switching noise is also possible (LC) - if necessary set the switching reg o/p a little higher, and use a linear after with a low-ish drop out voltage.
Regards, Orson Cart.