ljcox said:You should post your circuit. It is tedious for me and presumably the others to have to read through your verbal descriptions.
No, it is a P MOS device hence Vdd is negative wrt Vss.audioguru said:The Oriental clock IC maker has the terms Vss and Vcc mixed up.
Maybe this new counter cicrcuit needs its own supply bypass capacitors.
manoj.patil.1974 said:Folks,
Thanks for all the help. But none of the tips help !!! I tried removing C5 and adding 100nf bypass capacitors ........... CMOS circuit via an optoisolator pair to the clock IC just to isolate any wierd powersupply etc related problems ............. QUOTE]
Hi Manoj,
1. Did you go thro'my mail
2. Is the circuit almost similar to the datasheet circuit.( ther are 2 circuits there. -- one with +ve voltage and other with negative voltage working. --which one your clock followed. --i do understand the VDD Vss voltage supply reversal issue-- it is correct. that VDD is -ve here.
3. we have now to go deep into the ic details, whether the Display dring 60/ 50 Hz and clock counting 60 / 50 HX should be synchronous?? to be studied with ref to the datasheet.
it is delay and testing patience. continue analysis.it is only for experience not for a clock afterall.
All the best.
It is difficult to know, from this distance, what your problem is. So forgive me if I ask some questions that may be obvious.manoj.patil.1974 said:Folks,
Thanks for all the help. But none of the tips help !!! I tried removing C5 and adding 100nf bypass capacitors !!!
This should have worked if you did it correctly unlesss the 50 Hz / 60 Hz issue that I alluded to above is the problem.manoj.patil.1974 said:As i have posted earlier, i tried separate power supplier and connecting the CMOS circuit via an optoisolator pair to the clock IC just to isolate any wierd powersupply etc related problems !!!!
manoj.patil.1974 said:However, my larger problem persists. I have connected the CD4060 and CD4018 for power from the SC8560 power supply itself. But, when i connect the 60Hz output of CD4018 to SC8560, it goes into a flickering on LED as if its counting at a very high speed.
nura100 said:.................
i thought of two options for solving this Problem:
................
2) Eliminate the trafo and make the Clock and Display work on DC using Mosfets for switching.
i tried to replace the two diodes at the trafo with two transistors swtiching at 50Hz (Push-Pull) but the display shows 1P:03 etc.
need some expert help here, this Mux is eating my brains
and also whether the centertap should to be connected to GND or Positive (incase of DC operation)
arun
This what I'm planning to do. I have been waiting for a respose from Manjo and I was intending to ask him to measure the transformer voltage. But he has not responded yet.mvs sarma said:Hi Arun,
you try to drive the transistors with the derived crystal clock for cycle 1 and inverted crystal clock for cycle 2.
That should not be necessary as I think I can work out which signal needs to be inverted.mvs sarma said:if still problem, then interchange the cycle 1 and cycle 2 transistor inputs.
What do you mean by "the trafo output"?mvs sarma said:the trafo output can safely be used by commoning the anodes of diodes and witha filter condensor,as supply for the disply drive trasistors under reference, instead of using the halfwave rectified supply and trying to load it .
Hi Arun, Please try attached diagram.nura100 said:Hello Friends
i already have used the method suggested by ljcox in his diagram, but it doesn't work, when the sources of both the Mosfets are connected to VDD, the display shows some weird symbols which are undesired.
by the way my CD4013's Q & Q- outputs drive two gates of mosfets @ 50Hz
...................
nura
I had not thought that the Vdd supply voltage would not be adequate to supply the display, but, in the original arrangement, obviously the energy comes from the transformer.nura100 said:Hello Friends
i already have used the method suggested by ljcox in his diagram, but it doesn't work, when the sources of both the Mosfets are connected to VDD, the display shows some weird symbols which are undesired.
by the way my CD4013's Q & Q- outputs drive two gates of mosfets @ 50Hz
at the first glance it looks very simple to do away with the Trafo and replace with Push-Pull Transistors,
it is not mere swtiching of the Transistors alternately that will solve this problem
but if we have to imitate the Center Tap Trafo, i think we may have to use a
H-Bridge Setup to convert Battery DC into AC
How about a DC-DC converter using CD4093 for Driving PMOS Clock IC?
ljcox your thought on this
nura
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