# DC DC switching regulator

Discussion in 'General Electronics Chat' started by ManeeshaN, Apr 29, 2010.

1. ### ManeeshaN Thread Starter New Member

Feb 17, 2010
8
0
hi ,

I am using a switching regulator to convert 15V to 5V.
can someone please tell me the formula to determine the power consumption of the switching regulator.
its urgetn.

2. ### mik3 Senior Member

Feb 4, 2008
4,846
67
Its 15V times the input current.

3. ### ManeeshaN Thread Starter New Member

Feb 17, 2010
8
0
and how do you arrive at that..
dont we need to do somthing like in linear regulator:
(Vin - Vout)* Iout

oe dont we need to consider efficiency of the regulator for this..?

4. ### mik3 Senior Member

Feb 4, 2008
4,846
67
I told how to calculate the total input power to the converter.
If you want to calculate the lost power in the converter then:

Lost power=Vin*Iin-Vout*Iout

5. ### ManeeshaN Thread Starter New Member

Feb 17, 2010
8
0
yes I think there I am,..
Pin-Pout is the power consumed by the regulator..
but if i calculate(Pin-Pout)/Pin what do I end up with..?

6. ### mik3 Senior Member

Feb 4, 2008
4,846
67
It is not the efficiency but it can be used as another way to measure efficiency. It will give you the ratio of the lost power according to the input power.

Efficiency equals Pout/Pin.

Apr 5, 2008
16,954
2,957
Hello,

I would say Pin = Pout / efficiency factor.
Pin = Iin * Uin
Pout = Iout * Uout.
The efficiency factor can be between 0.8 (for a poor DC / DC converter)
and 0.95 (for a reasonable DC / DC converter)

Bertus