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Time to violate some IC's!

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mstechca

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I managed to roll my own PLL detector using 1 555 timers as the local oscillator, a D flip-flop from a CD4013 IC, an XOR gate from a CD4077 IC, and a NAND gate from a 74C00 IC.

As you can see, I have 3 unused NAND gates, 3 unused XOR gates, and 1 unused flip-flop. I want to be able to compress the circuit more, and be able to knock off something without me buying that 567 PLL chip, because bus service over the holidays is very limited, and I will have to wait another two weeks!

so instead of me twiddling my thumbs, I want to arrive at a solution.

I want to at least knock off one IC, and still come up with a PLL detector.
I think the easiest way is to somehow make a 555 as a flip-flop, and knock off the CD4013 IC. at least then I save 1/2 an IC.

Unless there is a better solution (besides buying new analog IC's), I will research.

I used the title because I might be able to use an IC that was supposed to be used for a different purpose.
 
You must have forgotten to post your circuit. You could use the second D type as an oscillator and thus eliminate the 555.

Post your circuit so we can comment further.
 
I didn't exactly forget, but it is posted below.

I made a few modifications. The 4077 is a XNOR gate, not an XOR gate.

I also decided to use a NOR gate instead of a NAND gate, for error reduction. The output is true if and only if the circuit determines that the 555's aren't completely in sync.
 

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Your circuit violates the very 1st spec on the datasheet for a 555 timer, its supply voltage.

Your 3V battery's voltage will drop to 2V over its life, so the ordinary Cmos parts that have a minimum operating voltage of 3V will also have their supply voltage spec violated.

An LMC555 Cmos 555 is guaranteed to work with a supply voltage as low as 1.5V.

The minimum supply voltage for an LM567 is 4.75V, so might not work when a 6V battery drops to 4.0V over its life.

That's why I use 74HCxx logic gates in my 3V Ultra-bright Chaser project, their minimum operating voltage is 2.0V.
All 74HC4046 ICs are different so you need to see each one's datasheet for their specs.
 

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You can make a set-reset flip-flop out of cross-coupled NOR gates, although the outputs will both be low if both inputs are high, while the outputs of a 4013 will both be high if set and reset are both high.
You can also make a bang-bang phase detector out of a D flip-flop (one input into clock, the other into D).
 
My analysis of your circuit indicates that U3 output may be what you are looking for, but Murphy's law says that RESETand U5 signals will not be the same frequency, so the analysis is meaningless anyway. Since Q and not-Q are replicas of U5 and RESET, do away with the 4013 and use the signals direct.
 

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I already made the design. Thanks Ron.
 
I got rid of the 4013 flip-flop and used 2 NOR gates to make a flip-flop instead. This saves me a chip.
 
yes, otherwise I would be adding more questions.
 
Here's my circuit modification:

I pass the outputs of each clock through an XNOR gate and the output of that is connected to one input of an NOR gate. The other input of the NOR connects to Q' (opposite of Q).


The 4013 works as a bistable multivibrator, where SET and RESET are the only pins used for action.
As soon as the first remote pulse is set high, the SET pin becomes high, Q is high, and the local clock turns on and starts high. Up to this point, both clocks outputted the same value, and the NOR gate outputs a "0" because of this.
As soon as one of the clocks goes out of sync (interference can cause this), The NOR gate outputs a "1", because The XNOR output is a 0, and Q' is a 0 because Q is a 1.

And the NOR gate never outputs a "1" when the 4013 is not set.

When reset is activated, the action starts all over again.
 
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