Hey guys!

I've checked a few posts on the forum and I tried several things, but nothing seems really appropriate for me.
I need to make a power supply for the servo I have (Multiplex Rhino Pro SHV Digi 4). I will run this on a car battery.

There are several things I can do. I can buy a cheap ass dc/dc converter (which I did and it isn't reliable). I can build a DC/DC converter (which I have 0 experience with and might take a lot of time). I can just take a bunch of LM317's and parallel them but they need to be cooled. Well, that is not a big problem but I have one big coolingblock. That coolingblock is connected to a bunch of other components. Those are insulated, but I don't want a voltage on the coolingblock.

Also, when the regulator/converter breaks I don't want it to put the input voltage on the output.

I checked this post on the forum and it looked very promissing, but when I simulate it myself it does not work the way I want it to.

Looking forward to your suggestions!
Thanks in advance!

 

Hey guys!

I've checked a few posts on the forum and I tried several things, but nothing seems really appropriate for me.
I need to make a power supply for the servo I have (Multiplex Rhino Pro SHV Digi 4). I will run this on a car battery.

There are several things I can do. I can buy a cheap ass dc/dc converter (which I did and it isn't reliable). I can build a DC/DC converter (which I have 0 experience with and might take a lot of time). I can just take a bunch of LM317's and parallel them but they need to be cooled. Well, that is not a big problem but I have one big coolingblock. That coolingblock is connected to a bunch of other components. Those are insulated, but I don't want a voltage on the coolingblock.

Also, when the regulator/converter breaks I don't want it to put the input voltage on the output.

I checked this post on the forum and it looked very promissing, but when I simulate it myself it does not work the way I want it to.

Looking forward to your suggestions!
Thanks in advance!

If you don't want punch through on switch failure, you should consider a transformer coupled design - its a failing common to both buck and series pass types.

A basic flyback with step down transformer should do the trick. Primary side regulation sensing is less accurate, but if you don't need input/output isolation - secondary side sensing is simpler enough.

 

I would use a buck down converter chip like Lm3150, less heat waste.


http://www.ti.com/product/lm3150

 

Thank you for your reactions! The lm3150 looks really goed maybe I'll even try that.
I did something that also does what I want (I think). I paralleled 2 of those LM1084ADJ chips. I think this does the trick as well, but I might be wrong. Probably not as efficient as the LM3150 but it is functional.