200kHz HF Transformer needed

piezo amplifier 500v

The sitemaps aren't understandable, I think. Just garbage.

Basically, you can expect that a solution with a rather small transformer is possible, cause it already exists. That's reassuring. I have difficulties to match the impedance measurement at 200 kHz (very lossy capacitor) with the waveforms. Has it been taken under identical conditions (e. g. medium load) and with the same device? It seems not helpful in calculating a resonant transformer that apparently exists ih the measurements. A solution could be to treat the impedance as unknown in detail and design the transformer by trial and error. The basic properties can be determined with lower voltage, without considering 1000 V isolation. That makes it easier to modify the transformer by simply adding or removing some turns.

transformer yourself

Thanks again it is very helpful.

FvM said:

Has it been taken under identical conditions (e. g. medium load) and with the same device?

Click to expand...

Yes it was exactly the same device and the same load (transducer measured outside the circuit then connected back and measures its voltage).

Could it be that the 470pF capacitor (2kV) parallel at the transducer is needed to get the resonance frequency (although I think it will consume much power)?

I also don't know if the there is a great influence of the input impedance of the receiver part connected across the transducer. (Manly a 220pF 2kV cap and a diode in series, these both parallel to the transducer. Receiver measures across diode).

1. What is a good point to start with trial and error (are there some rules of thumb, which are of great importance)?
2. What effects should I see at the signal on the transducer to know that the secondary windings are enough (to get at the resonance of the circuit)?
3. Is it a good idea to take lower primary windings and make enough secondary windings and then increment the number of windings primary until the right voltage? Or just start with much lower driving voltage (e.g. 1V instead of 12 driving pulse) because the primary windings influences the characteristics of the transformer to much.

But if someone has a better solution (without transformer or in another way used) I will be glad to hear.

With kind regards

sonar transducer spice model

I meant particularly media load (transducer diped into water as in normal operation?). This has some influence on the impedance. One waveform seems to show a near (0.7 m) echo.

The parallel capacitor may not me necessary in any case, but you can assume that the existing circuit depends on it. Also the capacitor used to decouple the receive signal is effectively connected in parallel to the transducer and has to be considered when dimensioning a resonant transformer. A capacitor however doesn't consume power, at worst losses from reactive currents may be increased.

Personally I would try to determine an equivalent circuit for the transducer and evaluate the transformer parameters in circuit simulation.

calculate hf transformer

have a look to airmar development kit simple schematic for the issue . Of course the actual design could be much complicated than it looks there.
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May be you can find more info on transformer data from airmar page. I remember one Australian page with rough transformer estimation unfortunately i dont remember link.

Yet there should be murata page with its app note which describes kit for 40 Khz low power sonar schematic. But it is not published in internet and i do not own it either.

Whatever you trying to do is to match impedance of that transducer to power stage so most probably custom design will be needed .

yet some description:
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and finally "The Design of Matching Systems For Piezo Elements"
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