Quote Originally Posted by Art View Post
Hi Guys,
Is there a less power consuming device than the 7805 regulator out there?
Sure, there's lots of good switching regulator circuits out there that are WAY more efficient than using a linear regulator (especially with high input voltages)

What is everyone using to power their 5 Volt pic projects nowadays?
I usually use a 7805....

I'd like a very conservative way to regulate say 25-30 Volts (similar to the 7805),
but only need low current 5 Volt supply.
78L05?

Seriously, what is your dissatisfaction with using a 7805?

Efficiency? ANY linear regulator is grossly inefficient with a high input to output voltage ratio...
Consider the math. If Vin = 25v and Vout = 5V, and you expect 100mA of current, then the output power is 5v * 0.1A = 0.5W
Power wasted in the regulator is Vin - Vout * Iout. So... 25 -5 * 0.1 = 2.0W.
I think that about sums it up, eh? With 25 V in and 5V out, 20 % efficiency is the BEST you can expect from a linear regulator.

Time to look at switching regulators if you want high Vin and low Vout with decent efficiency.

If I've missed the mark and it's not about raw efficiency, then what's the problem? What's your application and current requirements? Maybe someone can suggest a better regulator method.


steve