Please read the previous post for the continuation...
Hi Aliman,
I am interested to follow the output stage exactly as given in your square wave design. I want you to include all the MOSFETs - NP as well as PN along with the buffer transistors and their base resistors.
The logic is very simple, if the output stage is responding and working well with the signals from the IC 4069, it should do the same with the signals from the 4017 ICs, after all both the designs are producing square waves (our design is producing a chopped one though.)
The voltages that you are getting are absolutely fine and the differences are too trivial to produce any effect on the circuit, moreover, very unlike the transistors, for MOSFETs its the voltage that matters and not the current and thats why the buffer transistors become very important and must be included.
I think it will be also important to include 10K resistors from the base of each buffer transistor to GROUND.
I wont be able to help you with the MOSFET types, as I myself am not quite knowledgeable with these devices, but the above modifications should hopefully set things in the right order.
Thanks and Best Regards.
Hi Aliman,
I am interested to follow the output stage exactly as given in your square wave design. I want you to include all the MOSFETs - NP as well as PN along with the buffer transistors and their base resistors.
The logic is very simple, if the output stage is responding and working well with the signals from the IC 4069, it should do the same with the signals from the 4017 ICs, after all both the designs are producing square waves (our design is producing a chopped one though.)
The voltages that you are getting are absolutely fine and the differences are too trivial to produce any effect on the circuit, moreover, very unlike the transistors, for MOSFETs its the voltage that matters and not the current and thats why the buffer transistors become very important and must be included.
I think it will be also important to include 10K resistors from the base of each buffer transistor to GROUND.
I wont be able to help you with the MOSFET types, as I myself am not quite knowledgeable with these devices, but the above modifications should hopefully set things in the right order.
Thanks and Best Regards.
Hi Swagatam, what if I replace the buffer transistor with one that has a higher collector current. Would that make a difference ?
Also you mentioned adding 10K resistors, because there already is a 10K resistor from the 4069 to the base of the buffer transistor, so you want me to add another 10K from the Base to ground , correct ?
I dont have any PNP mosfets right now. But if this output stage works with the Square wave circuit , with some minor changes our PWM circuit should work also.
Sincerely Ali
Hi Aliman,
I think we better stick to the tested design given below, so lets follow the circuit as given in your square wave design... we can always modify it once it starts working.
Thats correct... The 10K resistor from the base of the transistors to the ground will ensure that every time the diodes stop conducting the base receives a ground or a low logic level and switches OFF completely.
Yes..of-course, if it starts working then the issue gets over and we wont need to include the PNPs.
Best Regards.
Continued HERE,
I think we better stick to the tested design given below, so lets follow the circuit as given in your square wave design... we can always modify it once it starts working.
Thats correct... The 10K resistor from the base of the transistors to the ground will ensure that every time the diodes stop conducting the base receives a ground or a low logic level and switches OFF completely.
Yes..of-course, if it starts working then the issue gets over and we wont need to include the PNPs.
Best Regards.
Continued HERE,
