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Low Voltage Suppression

Hello,

I have a bit of an odd problem with voltage suppression. I am trying to get rid of a small (700mVpp on a 12VDC line) spike coming from a DC fan that can possibly feed back into sensitive circuits. I have designed with circuits that needed protection from kV+ spikes but nothing this small. Do they make TVSs with a very tight control (+-100mV) around the breakdown voltage or is there another component I should be looking at?

Thanks, Matt

Reply to
Matt
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Can you afford to lose some of the 12V? A source follower made from a power MOSFET can make physically small parts filter quite low frequencies. A 10V regulator would also work.

Also, try putting a capacitor right on or near the fans electrical connections. You want to provide a low impedance path for the spikes that doesn't go near the small signal paths.

Reply to
MooseFET

Don't supress the noise, slow it down with enough capacitance and then regulate it out by running the sensitive circuitry off of a lower voltage (say 8VDC).

Best regards, Spehro Pefhany

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"it\'s the network..."                          "The Journey is the reward"
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Reply to
Spehro Pefhany

IIRC..ittty biity spikes are not controlled by transient suppressors. An ideal zener might..but doesn't exist.

Heres some ideas...

  • series regulator with high PSRR
  • shunt regulator
  • inductor
  • capacitor
  • Replace the fan with heat sinking or make a cooler design.
  • Make the electronics more noise immune
Reply to
D from BC

try this:

12V ------>|---+------ to fan | ===== | | -+--

Bye. Jasen

Reply to
Jasen

Anyone who would ask a question like that has no business posting to SED or even touching anything electronic...

Reply to
Fred Bloggs

Yeah...it's a lame Q but how about this for the hot shot designers..

Can the ideal zener be created? And would it be useful?

I propose this recipe:

1 super fast op amp #???? 1 super fast transistor

It's basically just a super fast version of a TL431.

World's fastest transistor: (old article)

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1Ghz Op Amp (at Av=1)
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If everything is fast enough...it could clip slow spikes. A programmable TVS circuit! D from BC

Reply to
D from BC

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