Yes, Mike, that's why I'm keeping this discussion in this thread, including discussion of a three amp version. It's still the same schematic.

Thanks!

 

I would not make that assumption. As the frequency increases the amount of core required decreases.

So does the size of the capacitors.

 

One more thing, after looking at the requirements. johnyradio said:

• Supply: AC 100 kHz, 10V
• Output: DC 5V @ 30 mA, isolated, continuous
• Footprint: L 10mm x W 10mm x H 5mm
• Budget: $1 (preferably $0.50)

Actually, two more things: No statement as to the regulation or stability!
Second thing: That price target says that it is for production in a product sold for profit. That means "commercial rates apply" because this is not a hobby type project, nor an experimenter thing, nor a "maker" venturing into a new realm.

 

No statement as to the regulation or stability!

Regulation came up earlier in the conversation, and I asked what the sources of instability would be. I suggest

• Variation in the supply. I'm confident there won't be variation in the supply, simply because I control the supply so I can make sure it's stable.
• changes in load: Will load affect capacitance or regulation? I can ensure that my load never exceeds max current.
• changes in temperature: How will temperature affect capacitance of a capacitor, behavior of the bridge rectifier, or regulation?

not a hobby type project, nor an experimenter thing, nor a "maker" venturing into a new realm.

How does that affect circuit behavior or requirements?

 

That is a fair question: " How does that affect circuit behavior or requirements? " It does not affect the circuit behavior or the requirements. Post #63 provides the details.

 

That is a fair question: " How does that affect circuit behavior or requirements? " It does not affect the circuit behavior or the requirements. Post #63 provides the details.

You said "commercial rates apply". BOM cost goes down with volume. I'm not counting manufacturing cost in my target BOM cost.

 

Neither was I.

 

the price target says that it is for production in a product sold for profit.

Target price may suggest that it is for a product sold for profit, but not exactly. It's to raise revenue, but not for profit. All revenue will benefit a nonprofit electronics mentoring project, for disadvantaged teenagers. So it's a plus that BOM cost goes down with volume. We taught underprivileged teens in a dangerous neighborhood how to build boomboxes for 3 yrs. Now i'm developing our new boombox electronics. I'm grateful for everyone's electronics advice.

 

• Unipolar on primary: Can we achieve galvanic isolation with a unipolar square wave source, to enable half-bridge instead of full-bridge rectifier? Would it still require 2 input caps? Could we make the square wave pulsewidth asymmetrical to increase the on-time of the voltage?
• Unipolar on secondary: Or convert it to unipolar on the secondary?
• Bipolar: With a bipolar square, can we obtain a center-tap with cap-iso, to enable half-bridge instead of fullbridge rectifier? Ideas for a center tap:

or an op amp circuit?

 

@crutschow Is this circuit bipolar transparent? I mean, will the AC voltage and current on the secondary be the same as the voltage in current on the primary?

For example if the input is a unipolar positive only square wave, then will the output should be the same unipolar positive only square wave? If the input is a bipolar sine wave, then will the output should be the same bipolar sine wave.



In: Out:

In:


Out:
?