- #1
ssb2245
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Switching frequency, phase multipliers, motherboards. Too many questions!
So i want to introduce myself, i went to Georgia Tech, and I got my BS in Biology, but ECE has always been kind of alike a hobby of mine. So i really like computers, but after interning in a engineering firm i decided to just leave it as my hobby. I have taken a handful of ECE courses so I understand the basics. I have a lot of questions that i need answered.
First off, switching frequency of buck converters. Is there anyway switching frequency could increase the amount of current reaching the processor? As i know is increased switching frequency decrease ripple, it also decreases overshoot, and it decreases efficiency and increase temperatures as a result. As i also know it in modern day motherboard VRMs switching frequency is directly related to transient response, and that capacitor series resistance is a huge problem to transient response. So this means that smaller VRMs(less phases) usually have higher switching frequencies and higher bulk capacitance? it doesn't make sense, to me that i see smaller phase vrms and they have much more bulk output capacitance than does a board with let's say 24 phases which might have a 75% less bulk output capacitance. Could someone clarify this more for me?
Now i saw this board, its made by gigabyte, and it has a 24 phase vrm, it has physically 24 driver MOSFETs, 24 inductors(chokes), and only a 6 phase PWM. Now the PWm is made by Intersil and they use a phase doubler to achieve 24 phases. I want to know how this works? There are 18 of these phase doublers, so the initial 6 each can do two and then those can do 2 more each. I want to know what type of tech they use? do they hurt transient performance so much by dividing teh switching frequency each part of the way? from 1mhz to 250khz? OR i read in one of their patent applications (intersil) like 50 different ways to make a phase doubler. One of the most appealing concoctions was for a IC that puts the full switching frequency to one phase until it reaches output current then automatically switches to the other phase, so it basically switches really quick and provides double the phases, so each phase still works out of phase.
here is the patent application: http://ip.com/patapp/US20100079175
another question, is there anyway to preserve switching frequency when only doubling the number of phases a PWM can handle? Like let's say we want a 12 phase VRM on a 6 phase PWM but we want to keep the switching frequency at it's highest.
one more thing, i suck at identifying electronic compoenets. Who makes this inductor? supposedly can deliver 50a of current:
Thanks for all your help! nice forums BTW!
So i want to introduce myself, i went to Georgia Tech, and I got my BS in Biology, but ECE has always been kind of alike a hobby of mine. So i really like computers, but after interning in a engineering firm i decided to just leave it as my hobby. I have taken a handful of ECE courses so I understand the basics. I have a lot of questions that i need answered.
First off, switching frequency of buck converters. Is there anyway switching frequency could increase the amount of current reaching the processor? As i know is increased switching frequency decrease ripple, it also decreases overshoot, and it decreases efficiency and increase temperatures as a result. As i also know it in modern day motherboard VRMs switching frequency is directly related to transient response, and that capacitor series resistance is a huge problem to transient response. So this means that smaller VRMs(less phases) usually have higher switching frequencies and higher bulk capacitance? it doesn't make sense, to me that i see smaller phase vrms and they have much more bulk output capacitance than does a board with let's say 24 phases which might have a 75% less bulk output capacitance. Could someone clarify this more for me?
Now i saw this board, its made by gigabyte, and it has a 24 phase vrm, it has physically 24 driver MOSFETs, 24 inductors(chokes), and only a 6 phase PWM. Now the PWm is made by Intersil and they use a phase doubler to achieve 24 phases. I want to know how this works? There are 18 of these phase doublers, so the initial 6 each can do two and then those can do 2 more each. I want to know what type of tech they use? do they hurt transient performance so much by dividing teh switching frequency each part of the way? from 1mhz to 250khz? OR i read in one of their patent applications (intersil) like 50 different ways to make a phase doubler. One of the most appealing concoctions was for a IC that puts the full switching frequency to one phase until it reaches output current then automatically switches to the other phase, so it basically switches really quick and provides double the phases, so each phase still works out of phase.
here is the patent application: http://ip.com/patapp/US20100079175
another question, is there anyway to preserve switching frequency when only doubling the number of phases a PWM can handle? Like let's say we want a 12 phase VRM on a 6 phase PWM but we want to keep the switching frequency at it's highest.
one more thing, i suck at identifying electronic compoenets. Who makes this inductor? supposedly can deliver 50a of current:
Thanks for all your help! nice forums BTW!