Low-noise isolated DC/DC

Aug 09, 2020 27 Replies

The peak wavelength for a 2400 K black body (incandescent lamp) is at

1.2 um, thus a large portion drops outside the silicon solar panel response,

Admittedly a lot radiation falls also inside the panel response. Some have used such light sources even for generating visible light with very bad efficiency for moe than a century :-).

The problem with sine waveform is that the output voltage would depend heavily on the load. Might be a problem if you depend on PSR. A bipolar rectangular waveform will keep the V_OUT rock-stable.

This is a multichannel sigma-delta, not exactly sure how to sync it with anything.

Best regards, Piotr

Hmm, an isolated Cuk, I forgot about this one. Thanks!

I expect no more than +/-20% load change at 300mW, probably less. Custom magnetics are not an issue, so stealing 200mw more for logic is attractive.

Best regards, Piotr

There's not a lot of difference between rectifying a 12 volts p-p sine vs rectifying 12 volts p-p square wave. A sine is pretty flat on top. I'd lost-regulate some anyhow.

I was also considering a more conventional push-pull drive into a transformer, but with slow, trapezoidal edges. That pretty much eliminates using any stock driver chips.

I have a couple of weird constant-amplitude sinewave power converters I need to Spice. One is a power Colpitts, and one is a strange resonant phase-shift oscillator.

I'm reading about WWII torpedo development. Colpitts himself was an important player in that. The Fido air-dropped, antisub, semi-intelligent acoustic homing torpedo was impressive, for being developed fast and using tubes, and for working at all.

John Larkin Highland Technology, Inc Science teaches us to doubt. Claude Bernard

TI has some cool logic isolators with power isolation included, with highside power enough for other gadgets.

John Larkin Highland Technology, Inc Science teaches us to doubt. Claude Bernard

This is what the LT3439 does.

I have good experience with the two-transistor current-fed Royer. The output was a sine, at least visually on the scope -- I didn't bother to measure its quality any deeper.

Some reading on the German V2 might be interesting to you too. Those guys achieved perfection with magamps.

Best regards, Piotr

That's interesting. It might even be worth $8.73. Plus the cost of a custom transformer.

John Larkin Highland Technology, Inc Science teaches us to doubt. Claude Bernard

If you need duty cycle control, then the LT3999 would be an option too. Same principle, just more functionality.

Best regards, Piotr

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