Voltage ripple

- H
- Hammy
  
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posted
16 years ago

Sun, Mar 30, 2008 8:18 PM

I'm measuring the output ripple on my flyback (60 kHz @10W). I'm using

2 polymer aluminum caps 16V 470uf 9mohm 100 kHz ESR. The peak secondary current is 5 Amps full load this should give about 35mV ripple. I'm measuring 140mVpp ripple on the output. I'm not using the ground lead from my probe but the small wire; I'm also taking the measurement right in the terminal blocks. Is the spike just RF pickup from the leads? I've tried bypassing it with leaded ceramic caps based on an FFT with limited success.

Any suggestions?

Heres a capture of the scope measurements. CH1 is the output ripple CH2 is the current sense signal.

formatting link

Thanks

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- P
- Phil Allison
  
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posted
16 years ago

Sun, Mar 30, 2008 11:41 PM

"Hammy"

** OK - so far.

** Huh ??

Try using a co-axial cable ( with BNC on one end) instead of a scope probe.

Might lose that RF glitch altogether then.

..... Phil

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