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| Created | January 07, 2017 |
| Last modified | January 07, 2017 |
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Just made one very similar to this, it was for a flying capacitor voltage inverter. I used the same inductor value and 100uF caps. No damping resistor. Input 9V dc, load 20mA. It was very successful in removing switching noise as viewed on a scope. |
January 08, 2017 |
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Oh cool. Were the capacitors in the same location as my schematic? |
January 11, 2017 |
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Yes, see my website at http://mike-wsm.org.uk/psbatt.html |
January 11, 2017 |
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Sweet. Did you happen to look at the ripple voltage with an oscilloscope? |
January 12, 2017 |
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From memory at C2 it was about 100mV and at C1 about 1mV, as expected by calculation of and XL1=2pifL1 and XC2=1/(2pifC2) at ripple frequency. For your values I get 0.0016 or -56dB for C2 to C1. To work out noise on C2 you need to show generator impedance say 50 ohms, Then noise on C1 is 0.08 or -21dB below generator voltage noise. Assumes low esr in caps at 400kHz. May need to use 100nF in parallel. L1 has parallel pFs which I have ignored. Quick calcs, please check! |
January 12, 2017 |
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PS - I see you make your circuits public. I've never done this, what protection is there against anyone, er, experimenting and making changes? |
January 12, 2017 |
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I don't know if someone can save over my work if I make it public. I assume they can. I started making (some) of my circuits public because whenever I write an Instructable, I often link to the circuit simulation so that people can try the design before they actually build it. On one of my circuits, someone left a comment that was really helpful/insightful. I decided to intentionally make some designs that I was a bit skeptical about public hoping someone would chime in with some wisdom and experience. Hahaha. And here you are! Seriously, thanks for the tips. I need to make a clean DC signal (<10mV) from a switching converter and was a bit worried that this implementation would be a bit too simple to get the job done. |
February 05, 2017 |
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