Bipolar PI design

[pechkata]

Is this the switch you are talking about...?

[GeoMax]

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.

Like this...

[Detectorist#1]

Hi pechkata,
The connections of BC807 in these level shifters are totally wrong. If gating pulses from uP are negative( +5V -no gating pulse and 0V - pulse) - emitters have to be connected to +5V and 10K resistors have to be connected from collectors to minus 5V supply. The control signals have to be taken from the collectors. If gating pulses from uP are positive ( 0V - no gating pulse and +5V - pulse), the emitters of BC807 have to be connected to corresponding outputs of the uP and the bases have to be connected to GND via 10K resistor. The output signals have to be taken from the collectors and the collectors have to be connected to minus 5V supply via 10K resistors.

[Detectorist#1]

Hi GeoMax,
Yes! This is right connection.

[pechkata]

That's how I understand it...

[Detectorist#1]

Hi pechkata,

The right picture is wrong! Read carefully my post #108 - " If gating pulses from uP are negative( +5V -no gating pulse and 0V - pulse) - emitters have to be connected to +5V and 10K resistors have to be connected from collectors to minus 5V supply. The control signals have to be taken from the collectors." In this case, the bases of the transistors have to be connected via 10K to 47K resistors to the control signals of uP. Voltage converters will be inverting in this case.

[Carl-NC]

Here are the two ways -- common-emitter & common-base -- side-by-side. You can see they are exactly the same circuit and work exactly the same way but the CE version inverts and the CB version does not. Eduardo, use the CB version.

[pechkata]

Hi pechkata,

The right picture is wrong! Read carefully my post #108 - " If gating pulses from uP are negative( +5V -no gating pulse and 0V - pulse) - emitters have to be connected to +5V and 10K resistors have to be connected from collectors to minus 5V supply. The control signals have to be taken from the collectors." In this case, the bases of the transistors have to be connected via 10K to 47K resistors to the control signals of uP. Voltage converters will be inverting in this case.

Sorry, Vlado, but I didn't understand anything from this google translator...
If he had drawn it...

[Detectorist#1]

Hi pechkata,
Just see pictures in post #112 from Carl. This are the variants if you want inverting or non-inverting scheme.

[eduardo1979]

Thank you very much for the clarification. It has become clear to me that in my case I have to use the common base configuration.

[dbanner]

not possible to use a 4011?

[Detectorist#1]

As what? As level translator?

[GeoMax]

Here are the two ways -- common-emitter & common-base -- side-by-side. You can see they are exactly the same circuit and work exactly the same way but the CE version inverts and the CB version does not. Eduardo, use the CB version.

Hi Carl / Detectorist#1

would this be now drawn correct?

[Detectorist#1]

Hi GeoMax,

Time-diagrams and schematics are OK. Just the value of the resistor R3 of common emitter connection have to be 47K, not 1K.

[GeoMax]

Hi GeoMax,

Time-diagrams and schematics are OK. Just the value of the resistor R3 of common emitter connection have to be 47K, not 1K.

Hi Detectorist#1,

Thanks for checking it. I think 10k for R3 should be okay. I did not paid attention to the resistor value of R3. The 1k is actually a "default value" when I pick a resistor from the library. I updated the value of R3 now to 10 to 47k Ohms.