Replacing 7805 with Buck converter.

[TonyAme]

I have a circuit board that I've made for the Teensy 4.0 and Audio board. Currently using a 7805 with a 9V power adapter. The 7805 gets very hot, so thinking about using the muRata OKI-78SR-5/1.5-W36-C. https://www.lcsc.com/product-detail/C6134431.html?s_z=n_q_C6134431&globalKeyword=C6134431
(Q1 is just a p-channel mosfet that I use for reverse polarity protection).

Would I need to change any caps in my schematic?
Thanks in advance, very much appreciated.

 

[BriComp]

Why not use one of these? It's a switch mode psu as a direct plug in replacement for a 7805.

 

[PaulStoffregen]

Looks like it should work. Your design has 4 capacitors, which is good. We've seen problems in the past where people didn't use capacitors, even some converters that said capacitors weren't necessary. They are needed.

 

[TonyAme]

Why not use one of these? It's a switch mode psu as a direct plug in replacement for a 7805.

Thank you. I tried your link but it didn't work. A "switch mode psu"? I will look into that too.

 

[TonyAme]

Looks like it should work. Your design has 4 capacitors, which is good. We've seen problems in the past where people didn't use capacitors, even some converters that said capacitors weren't necessary. They are needed.

Thank you for the input.

 

[kd5rxt-mark]

Thank you. I tried your link but it didn't work. A "switch mode psu"? I will look into that too.

Try <this UK specific link> or <this US specific link>

Hope that helps . . .

Mark J Culross
KD5RXT

 

[Angelo]

I used this one: https://www.digikey.com/en/products/detail/recom-power/R-78B5-0-1-0/2256232

 

[KenHahn]

Another option to consider with your current setup is to just use an AC/DC input with a lower voltage. If you used a 7V instead of 9V input, it would cut power dissipation in the 7805 in half.