EEVBlog #1116 - How to Remove Power Supply Ripple
Why Electrical Engineering Stack Exchange recommends it
Electronics Stack Exchange answerers point people to it when someone needs to clean up ripple or noise on a supply rail and linear regulators or bulk capacitors are not doing the job.
Recommended by 4 people across 5 different months, 2018 to 2023.
What it is
Dave Jones of EEVblog explains the capacitance multiplier circuit, showing on a whiteboard and at the bench how it removes power supply ripple far better than a typical linear regulator. He ends with a twist arguing the circuit is really a buffered low-pass filter, so the name is misleading.
What people said
Recommends Damien · 2018-09 · Electrical Engineering Stack Exchange · on “USB power cleaning”
It seems more to be a ripple voltage/current you are talking about. Linear regulator are not good at filtering ripple and are not device made for that. A good and cheap way to improve ripple is to use what is called a capacitance multiplier circuit [LINK] . [LINK] Those circuit are very good at reducing ripple without to have to add massive capacitor and have a cheap cost. To increase effectiveness, you can add several transistor or use darlington transistor as the value of the capacitor will be (virtually) increased by the transistor gain. A Nice youtube video explains it here. [this video] EDIT There is also off-the-shelve components that implements this principle, such as the AP1158 [LINK] .
Recommends rdtsc · 2018-09 · Electrical Engineering Stack Exchange · on “Common mode chokes in series”
Dave talks about Capacitance Multipliers [this video] in this video, might be useful if looking to experiment with other ideas.
Recommends Damien · 2018-12 · Electrical Engineering Stack Exchange · on “How to remove noise in inverter”
I guess you are hearing a 50-60Hz noise as the output of the transfo is not properly filtered. You need to add quite a bit of capacitor between the bank 1 and 2 to GND, they use battery but battery doesn't have fast transiant response. If this doesn't solve it, you can add a capacitance multiplier [this video] circuit between the transfo and the banks.
Recommends Romyo · 2019-08 · Electrical Engineering Stack Exchange · on “LM1117 3.3V output gives 4.2V”
As you didn't tell more about the circuit . That must be a noise problem mostly could be a ripple problem you have to stop ripples from being amplified by choosing the right capacitor values . 8.2.2.1.2 Adjust Terminal Bypass Capacitor The adjust terminal can be bypassed to ground with a bypass capacitor (CADJ) to improve ripple rejection. This bypass capacitor prevents ripple from being amplified as the output voltage is increased. At any ripple frequency, the impedance of the CADJ should be less than R1 to prevent the ripple from being amplified: 1/(2π × fRIPPLE × CADJ) < R1 (1) The R1 is the resistor between the output and the adjust pin. Its value is normally in the range of 100-200Ω. Fo
Recommends Deepak · 2020-10 · Electrical Engineering Stack Exchange · on “Cleaning power rail from switch mode power supply”
For a clean output voltage, I would suggest you to use a "capacitor multiplier" before LDO in your circuit. According to my tests, it can reduce noise to a level of 15mVpp. It is basically used where ultra-low noise is desired like in Current sense Amplifier. Please watch this video [this video] to implement it in your application. Best of Luck [LINK]
Recommends Damien · 2021-03 · Electrical Engineering Stack Exchange · on “How to smooth fluctuating DC from transformer?”
Use a capacitor multiplier circuit [LINK] . Video here [this video] [LINK] This circuit allows to smooth out ripple from the supply. Many people may advise to use some sort of LDOs, but LDOs aren't good filters.
Cites nagylzs · 2018-12 · Electrical Engineering Stack Exchange · on “Capacitor multiplier does not remove ripple”
I must be doing something very wrong, Dave from EEVBlog demonstrates the very same circuit here: [this video] and for him it is working.
Cites Viktor Hedefalk · 2018-12 · Electrical Engineering Stack Exchange · on “Capacitance multiplier for synth PSU?”
Noob alert. I'm about to build a pretty simple PSU for my modular synth project. I'm looking at a few schematics from popular sites and I've previously built a simple wall-wart one based on this from MusicFromOuterSpace [LINK] . [LINK] There are also lots of kits with these 7812/7912 pairs like this [LINK] . But then I watched this video [this video] on capacitance multipliers and just don't understand why this isn't used everywhere? I guess I'm missing something. What I mean is, it seems to be a really big thing to really reduce ripple on power for synth applications. The schematics I'm looking at are sticking really really big electrolytics in there to do that - it's like that's probably the bi
Cites Viktor Hedefalk · 2018-12 · Electrical Engineering Stack Exchange · on “Capacitance multiplier for synth PSU?”
The point he is making in the video about here [this video] is that regulators are really not very good at mitigating ripple from the input. But I guess this is all about higher frequencies on switched supplies, not mains ripple…
Cites jvnlendm · 2019-07 · Electrical Engineering Stack Exchange · on “Removing output voltage ripple in high voltage outputs”
I am looking to reduce the voltage ripple on a DC/DC converter operating at 5kV. I have looked extensively on the internet and have found multiple ways to reduce output voltage ripple, an interesting reference is by EEVBlog [this video] which uses capacitance multipliers with BJT/MOSFET/Darlington transistors. Multiple other sources state to use multi-stage LC filters, and high value capacitors, etc. However, when the output voltage enters the kV range, the use of inductors is avoided as much as possible, if possible. Furthermore the size of capacitors with large values rated for kV values are very bulky and again, would be avoided if possible. This brings limitations in the amount of voltage rip