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What is the voltage on pin number 4 (vdd)? I suspect that there will be exactly 5B. But I could be wrong. That's why I decided to ask you. Is it possible to measure it?
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I found only one photo of the "insides" of the block on the manticore. Judging by the photo in the transmitting part, the scheme is the same as in the Fisher CZ. Conditionally, of course, but the general meaning is the same.
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Fisher used the 18V transmitting stage to power the cz. Equinox uses a slightly different scheme: a 270 mkF electrolytic capacitor is installed sequentially on the TX coil. The same was done in Whites Spectrum v3i. In Equinox you wrote that the supply voltage of the transmitting part is 29V (practical maximum) If you calculate according to the nominal values of the circuit and datasheet for the Whites Spectrum v3i converterthen in turbo mode the power supply voltage of the transmitting stage was 32V.Comment
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Recently, I tried to simulate a comparison of a full bridge on n/p-mosfets and a scheme like in Fisher's Cz (most likely the same as in Manticore) in multisim. The only thing is that I chose the parameters of the TH coil such as in the deus FMF coil (I specified the approximate capacity). The supply voltage was 3.7V all the time. I conducted a simulation from 3 to 35 kHz and saw that the shape of the current in the TX coil is much better with the Fisher/Manticore scheme than with the full bridge scheme for 4 MOSFET. I can be wrong, of course, in my reasoning, but the model of the transmitting cascade according to the Fisher/Manticore scheme is more preferable for a VLF metal detector powered by 1 lithium battery. I set this task for myself.
The only thing is that I don't know what supply voltage of the output stage will be optimal. Previously, when I thought about a full bridge of 4 MOSFETs, I chose a range of supply voltage from 3 to 9V. I found a suitable dc-dc converter. But I did not take into account the feature of the full bridge on n/p MOSFETs and the adjustment of the supply voltage of this bridge. In addition, there was a problem with the bridge driver. Now, when I see the Fisher/Manticore scheme, nothing prevents me from using the n-channel MOSFET (ao4882, it is very good in terms of its parameters of capacity and charge of the shutters) and a more affordable MOSFET driver, connecting it to independent 5V. All that remains is to understand what voltage is optimal to apply to the TX fisher/manticore scheme.
In addition, in the multisim, I noticed that the Fisher/Manticore scheme allows you to achieve a higher current in the TX coil compared to the full bridge scheme on the n/p-channel MOSFETs with the same supply voltage.Comment
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Actually I was wrong, it is 6.7V between pins 1(vdd) and 4. The output is as you mentioned, via 270uF cap + 4.7uH inductor to suppress back EMF.Originally posted by JoyJo View PostComment
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And at this voltage of 6.7v, what is the voltage on AO4882 (or on the second electrolyte 270uF). Maybe the supply voltage of ao4882 is regulated together with the power supply of the hip2103 driver?Comment
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I think they are on separate supply rails. I think, by default, AO4882 supply is 25V, but I have it slightly elevated. All power supplies on Nox appear to be regulated one or the other way, if below battery voltage, they use regulators, if above, DC-DC converters.
It's interesting to see they use something different on the Manticore. It is strange though that it doesn't do much better, if at all, than the Nox 700/900 series. Intronik beats them all it seems in the depth department.Comment
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This seems strange. The half-bridge cz circuit only delivers half the voltage to the tx coil. Where as the full-bridge delivers the full rail to rail voltage. In your multi-sim it looks like mosfet 2B the drain and source are reversed?Originally posted by JoyJo View PostComment
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But this is the right statement. The upper p-channel mosfet is turned on incorrectly. Thank you for the correction!Comment
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I've been working on the bugs))) Yes, in previous simulations, I was a bit confused by the behavior of the full bridge))) I wasn't paying attention. Now I've corrected the simulation models.
I compiled the test results into a single Excel file, which is in the archive. I was interested in seeing the difference between the full-bridge and half-bridge designs with a center tap made of electrolytic capacitors.
The bridge supply voltage was always constant at 5.59 V. The control signal level was constant (3.3 V), and only the operating frequency varied in the range from 3 to 50 kHz in 5 kHz increments. The results may be predictable for some, but I found them interesting. I used the parameters of the transmitting coil from XP Deus FMF.
It seemed to me that a half-bridge with a capacitor-based center tap provides a smoother signal waveform in the 5 to 50 kHz frequency range. Moreover, due to the lower current amplitude in the TX coil, it allows for smoother adjustment of the TX transmit level by using a narrower supply voltage range.
It would be interesting to know what voltage Manticore uses. But for now, that's pure science fiction.Comment
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Intronik is Double Sine - that could explain its TX performance, or am I right?Originally posted by nordic View PostComment
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El Nino, long time no see. Hope all is well
Re Intronik, I have heard only it may be a sine wave. I'd like to buy one, but it is unavailable anywhere in Europe.
In regards to Nox, I have once omitted the inductor on the TXH line to allow back Emf through, it feels as if it helped with the depth a little, but it is hard to measure.Comment
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