help regulating voltage

hello, i have a circuit where my atmega328 is being powered by a 7805, this 7805 also powers a 3.3 regulator, and apparently this is too much for the 7805, since the input is 24V the efficency is pretty low, what can i do to solve this?

can i make the atmega be less consuming? or what other chip could i replace this for? this is my circuit

You are trying to get 5v from a 24v source. Yes, that is a pretty large drop. If you can't use a 12v (or close) source supply, then I suggest you use a switching regulator.

switching regulator? never heard of them, is there an especific one? just by the name i imagine a transistor doing a pwm something like that?


Either a switching reg or lower your input voltage .

Google "buck converter".

thx, i did a fast search, do i need to know the exact amount of current of the load?

What is the LM317 doing? What voltage is coming in to that bridge rectifier attached to the LM317?

the lm317 is the one supplying 24v, this is becuase I need 24 v for a sensor

do i need to know the exact amount of current of the load

You don't need to know the "exact" amount, but you should not draw more than the regulator is rated at. Better safe than sorry..

If im good at my estimates, i am not drawing more than .5A so i think i could design a 1a regulator, so i am trying to figure out how :)

input is 24v ouput is 5v iOutput 1a

You could use two of something like this, one for 5V and the other for 3.3v

That's a lot of current.Look at for step down regulators.

well i dont know hwo much current i am actually consuming, my sensor peak current is 70ma and the arduino takes about 100ma the nrf24l01 is about 40ma? im not sure

That’s a lot of current.Look at for step down regulators.

what does that mean. He requires a lot of current? What URL are you suggesting? Please put in a hyperlink tag. Did you find one that is less expensive (include shipping). Please give us the URL. Thanks

hey jack, could you help me design a buck converter under those specs? would it be cheap?

i found this MC34063A switchable regulator on a shop, but i just dont know how to wire it.

You don't give us a URL?

The example I presented to you cost $3.80. Do you find one less expensive. What's the URL ?

i am not buying it from here, a local store sells for $2.90, but i belive i need extra components

I don't know anything about that IC. I would suggest spend a dollar more, and get all the components on the board.

can you help me on how do i need to design it?