LM5022: Dual step-up boost for tube amp

Eduardo Esquembri

Part Number: LM5022
Other Parts Discussed in Thread: LM5020

I need to power a vacuum tube preamp, I now have two +-57V rails and need to raise this to at least +-120V (240V total with a center point).
I have thought about using the LM5022, I have obtained a schematic from Webench PD.

I have thought that it would be enough to duplicate the circuit and connect them in series to get the dual output, but I don't know if this would be correct.

circuit design:

over 2 years ago

0 Richard Fu22 over 2 years ago

TI__Mastermind 20330 points

Hi Eduardo,

If you want to double your output voltage, what you can do is add a voltage doubler or tripler circuit at your output, as shown in this design: https://webench.ti.com/appinfo/webench/scripts/SDP.cgi?ID=BD60A6F374E3E861

However, the downside here is that you will have lower current. You an also do this to generate a negative rail.

Please see the following references:

https://www.ti.com/lit/an/slva398a/slva398a.pdf?ts=1645833420512

https://www.ti.com/lit/an/slvaej3/slvaej3.pdf?ts=1645833362984&ref_url=https%253A%252F%252Fwww.google.com%252F

Regards,

Richard

0 Eduardo Esquembri over 2 years ago in reply to Richard Fu22

Prodigy 10 points

Thanks Ricardo, I think your proposal to use a duplicator is more interesting, I will see what I can find out about it.

As for the issue of maintaining the symmetrical power supply structure, I continue with the same doubt, now I have a symmetrical power supply, and I need to maintain the same structure after increasing the voltage.

The original supply provides 5 Amps per rail, and I only need 200 mA per rail.

I attach a drawing of my idea:

I have been searching and I can't find a Doubler that supports up to 60Vin, it seems that the idea of using LM5020 or LM5022, is the most suitable.

Regards,

Eduardo

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LM5022: Dual step-up boost for tube amp