Digital power supply

[Shevy]

What's a digital power supply and is it worth considering to include in a pc build?

[Princess Luna]

Quote

The actual means by which a PSU converts AC to DC is relatively unchanged between analog and digital.  There are different TOPOLOGIES like double forward, resonant mode LLC, etc., but that doesn't mean one PSU is digital vs. analog.

 

What changes is how the PSU's switching is controlled.  Whether they use an analog IC (like an analog PWM controller, for example) or an actual MCU.

 

Essentially, 99% of the PSUs out there are analog.  The cost delta between an analog IC vs. a digital MCU is like 20 cents versus $5.  So you're not going to see digital controllers in your $99 Gold PSUs.  Also, it's unnecessary.  Usually, digital control of the switching frequencies is only needed to achieve very high efficiency.

 

An analog controller is pretty straight forward on what it needs to do.  A digital controller like the kind TI makes to drive digital totem-pole PFC, for example, allows switching frequencies to change quickly under different loads.  On the secondary side, an analog IC basically takes 1 or 0 input to determine a 1 or 0 result.  Digital PSUs can take data from teh output voltages and report back to the PSU as to how it could function better.

 

Currently, the only truly digital PSU on the PC desktop market is the Corsair AXi.  But the server market has many digital PSUs from the likes of Delta, Lite-On, etc.

 

Some PSUs call themselves "Digital" because they have an IC that analyzes data to report to the user, but since the rest of the PSU is actually analog, it can't actually control how the PSU works.  For example:  The NZXT E Series PSU and the Corsair HXi PSU aren't really digital.  They're still analog.  But they both have an IC that can read output voltages, output power, etc. and report it to the user via software.  

 

[Spotty]

14 minutes ago, Shevy said:

What's a digital power supply

Expensive.

There's only a very small number of fully digital power supplies on the market and they're all in the region of several hundred dollars. It's not at all necessary. Your system/hardware won't care whether the power comes from an analogue or digital PSU.

 

I would recommend checking out this article over on Toms Hardware, along with the quote from JonnyGuru posted above. https://www.tomshardware.com/reviews/power-supplies-101,4193-16.html