Hoot, Since87, take a peek at this please

[UberBlue]

The both of you seem to be hard core twidgets and can shed some light for me. If anybody else knows jump in. I would have put it in Technical discusion (if it still existed), it really doesn't fit in GCRD, so I stuck it here.

I got a Fluke 867B graphical multimeter w/NIST tracing for christmas. Brand new.

I was feeeling bored so I decided to take a look at the voltage regulators on my motherboard. What I saw floored me.

As you can see, it's a 100.66 kHz square wave (or at least an atemp at) with an RMS voltage of 6.498V DC.

Honestly, I know how transistors work, it never dawned on me there's no reason for these to be different.

So I sat down and thought about this for awhile. The VR's are MOSFET's which are basicly high speed switches. I wondered if Frequency is load dependant, so I fired up prime95 and watched the frequency drop to 95 kHz and voltage drop to 5.989V. Pulse width stayed the same.

At first I was thinking pulse width modulation, but the pulse width doesn't change as far as I can tell, only the pulse repetition frequency.

Do the voltage regulators regulate by raising/lowering the frequency, in effect raising/lowering the RMS voltage as needed?

 

[Hoot]

Yes.

There is more than one way to regulate. Ole Hoot went to a Christmas party last night and he's working on restoring his brain cells today, so he won't be elaborating...

Hoot

 

[UberBlue]

Yes.

There is more than one way to regulate. Ole Hoot went to a Christmas party last night and he's working on restoring his brain cells today, so he won't be elaborating...

Hoot

Thank you. When you are feeling up to it, would it be possible to get a deeper explanation?

I'm used to dealing with transistors in audio applications where square waves are bad. I still jump when I see one.