PSU Ripple vs Voltage Regulation

[aymanhaq]

The title says it all. What is the difference bw the two and why does it matter? Looking for an in-depth explanation. Thanks!

 

[thor220]

This is like cause and effect. If the PSU doesn't handle heavy loads well, it causes the voltage to ripple (spike) allot. Running components out of voltage specifications can damage them. Larger ripples = higher chance of damage.

A good PSU will regulate voltage to a point where even under an instantaneous, heavy load, voltage will still remain very close to target voltage.

 

[aymanhaq]

This is like cause and effect. If the PSU doesn't handle heavy loads well, it causes the voltage to ripple (spike) allot. Running components out of voltage specifications can damage them. Larger ripples = higher chance of damage.

A good PSU will regulate voltage to a point where even under an instantaneous, heavy load, voltage will still remain very close to target voltage.

uhhhh...

all PSU reviews measure ripple and voltage regulation in different tests. I am assuming they are different things. I'm wondering what the differences are. You answer is...less than illuminating.

 

[thor220]

Ripple is the unwanted variation in DC current. DC isn't supposed to oscillate at all. When a PSU is put under load, it can cause the DC current to oscillate (ripple). Measured with an oscillator, this value is always in the form of an analog wave in tests and always targets a medium value.

Voltage regulation is the targeting and keeping of a set voltage. Good power supplies are able to keep very close to the target voltage.

The two are different but often if one is bad the other will be too. Ripple is absolutely not wanted. Obviously a power supply that's having issues converting AC into DC is going to have issues.

 

[ko888]

Voltage regulation measures how closely the PSU's DC output voltages adhere to the voltages defined by the ATX12V Power Supply Design Guide Specification across the full range of the PSU's output load. A PSU with perfect voltage regulation would have no variation in its output voltages no matter what load is placed on it.

Ripple voltage is an artifact of the AC to DC conversion process by the rectifier. It appears as a high frequency (i.e. choppers switching frequency or a harmonic of that frequency) AC voltage that is superimposed onto the DC output voltages. Capacitors are used to filter out the ripple but its not perfect so some ripple does still get through. Insufficient filtering in the PSU just means that the attached devices own filtering circuits, if they have a filtering circuit, will have to deal with the high levels of ripple. If the ripple is excessive it can cause damage to the capacitors by overworking them on the attached devices (e.g. motherboard, graphics card, HDD's controller board, etc.)

 

[aymanhaq]

Ok that makes ALOT of sense. So that leads me to another question. Can bad ripple regulation lead to buzzing/coil whine in PC components?

 

[ko888]

Ok that makes ALOT of sense. So that leads me to another question. Can bad ripple regulation lead to buzzing/coil whine in PC components?

Coil whine is due more to poor manufacturing tolerances of components or poor component quality.

 

[thor220]

Ok that makes ALOT of sense. So that leads me to another question. Can bad ripple regulation lead to buzzing/coil whine in PC components?

Coil wine occurs when an electronic device is being stress such that it generates a noise. Bad ripple cannot lead to coil whine but because both issues usually occur together on low quality parts, they are often associated.

 

[thor220]

Voltage regulation measures how closely the PSU's DC output voltages adhere to the voltages defined by the ATX12V Power Supply Design Guide Specification across the full range of the PSU's output load. A PSU with perfect voltage regulation would have no variation in its output voltages no matter what load is placed on it.

Ripple voltage is an artifact of the AC to DC conversion process by the rectifier. It appears as a high frequency (i.e. choppers switching frequency or a harmonic of that frequency) AC voltage that is superimposed onto the DC output voltages. Capacitors are used to filter out the ripple but its not perfect so some ripple does still get through. Insufficient filtering in the PSU just means that the attached devices own filtering circuits, if they have a filtering circuit, will have to deal with the high levels of ripple. If the ripple is excessive it can cause damage to the capacitors by overworking them on the attached devices (e.g. motherboard, graphics card, HDD's controller board, etc.)

Great explanation, much more clear than my own.