Bipolar PI design

[Emersonpaz]

Excellent video Carl congratulations, it was very well explained, I believe that if the VCO with the 4046 two tones was integrated into the bipolar project it would be a great improvement, I made an adaptation to the Polish pi

https://youtu.be/RDV93ZdeGhk?si=ekkBRbZmtrbz_A20

[ivconic]

Excellent job Carl!
That is what I would call a very well made video.
This is what I have asked/rebuked many forum members many times when they present their ideas.
Emersonpaz too, good video.

[pechkata]

Apologies to Carl and all forum participants...
The video did not show how many volts the peak of the final transistors is...
Something like that...

[Carl-NC]

At 9:14 it appears to be 250-300V.

[pechkata]

Sorry again, I didn't pay attention to the scope of the oscilloscope probe...
Thanks for the video and your time...
I'm glad there are people like you - stay alive and well...

[eduardo1979]

I have completed testing the Bipolar PI design and posted new firmware. I changed the timing to use 1 timer and is now all interrupt-driven, there are no polling delays. This gives the delay adjustments more resolution and more consistency.

Two things I don't like about the design. One is that the demods are a bit glitchy in that they pass through some transients. I don't know if this is a particular problem with the 4316 switches or what. I have not seen this in other designs I've done. Second is that the audio is not all that great. The 555 VCO does not have as much frequency range as I recall from when I breadboarded the circuit. And the transient glitches from the demods gives the audio a little it of a raspy sound. With a little tinkering, both might be solvable but I don't have the time right now.

Hi Carl.
I'm stuck and need your help.
I'm drawing the PCB for the Bipolar PI in SMD and I have a question regarding the 74HCT4316 as I see that it gives problems. Could I put a 74HCT4066 instead, making the corresponding modifications on the PCB on the power pins, since they are different? I've also thought about using a CD4066 and adding 4 voltage converters with 4 PNP transistors and 8 resistors just like in the Arduino Nano PI. In your opinion, which of the two variants would be the best?
I'm also going to use a CD4046 for the audio VCO.
Thanks in advance.

[ivconic]

I dug out this old pdf. 4046 can be used in many ways.
Good stuff.

[pechkata]

For Algan...

[Carl-NC]

Could I put a 74HCT4066 instead, making the corresponding modifications on the PCB on the power pins, since they are different? I've also thought about using a CD4066 and adding 4 voltage converters with 4 PNP transistors and 8 resistors just like in the Arduino Nano PI. In your opinion, which of the two variants would be the best?

Any 4066 will require the level converters since the clocks must be referenced to -5V. Once you do that, probably most any 4066 will work as long as it's rated to handle the 10V power supply. Whether one is better than the other often depends on the company who made it and what IC process they used. You have to test and compare.

[eduardo1979]

Thank you very much Carl for responding and clarifying my question. I'm thinking of using a HEF4066 and its four corresponding level converters. I'm thinking that when using level converters, the square waves of the four signals coming out of the PIC would have to be inverted. Am I right?

[Carl-NC]

Correct.

[eduardo1979]

Hi Carl and thanks again for answering my question.
I need one last favor from you, as I have no experience with PIC microcontrollers. I have only worked with AVRs and I don't have any kind of compiler for the PIC. Could you post a HEX file on the forum with the four signals inverted? This would save me a lot of work, as I have opted to use a HEF4066 and the four level converters. I'm in no hurry, do it at your convenience.
Thanks in advance.

[Detectorist#1]

Hi eduardo1979,

For controlling of 4066 no need to use inverting pulses from uP. Emitters of the PNP have to be connected to corresponding uP outputs and bases have to be connected to the Gnd via 10K-47K resistors. Thus, PNP will works as non-inverting level translators from 0/+5 volts to -5/+5 volts.

[GeoMax]

Hi detectorist#1

does this small circuit below shows what you wrote about the non-inverting level transistor circuit in post #103 (above)?

[Detectorist#1]

Hi GeoMax,

No. CD4066B have to be supplied from +5V and -5V. And the collector of BC557 have to be connected via 10K resistor to minus 5V supply.