How to determine ripple voltage?

[beerman]

From http://sound.westhost.com/power-supplies.htm

The required capacitance for a given load current and ripple voltage is determined (approximately) by the formula [1]...

C = ( I L / ΔV) * k * 1,000 uF ... where

I L = Load current
ΔV = peak-peak ripple voltage
k = 6 for 120Hz or 7 for 100Hz ripple frequency

Load current is covered, though I can't find anything on peak-peak ripple voltage. What number plugs in here?

 

[owdi]

plug in however much ripple you are willing to accept. Note the less ripple you specify, the larger the cap.

Dan

 

[beerman]

The next question: how much ripple is acceptable? Should I go off X percentage of +/- DC volts?

 

[owdi]

That depends entirely on your application. What is the power supply for?

Dan

 

[beerman]

Chip amp for a 5.1 application: 5 LM3886s at 4ohms (28v rails seems to be the suggestion from NSC on their LM3886 page for 4ohm use) connected to a home theater PC.

The current debate raging in my head is whether or not to DIY the subwoofer amplifier and include it in the same box, or if I should use a commercially available plate amp. Either way, the sub wants a considerable amount of juice.