I'm designing a circuit that will disconnect a connection when 5 consecutive square wave pulses are missing. If less than 5 consecutive pulses are missing then I want to reset the counting process.
_ _ _ _ 1 2 3 4 5 _ _ 1 2 3 4 _ _ In _| |_| |_| |_| |___________________| |_| |________| |_| |_ ____ Out ______________________________| |______________________
To give an idea:
I'm thinking of using a counter that will count the number of pulses. This will connect to a multiplexer, to initiate selection between counter reset or charge bank of cap(s). Bank of capacitors charge to reach 5V. This will be compared(op-amp) to ~4.9V.
The capacitors will initiate charge after each pulse, but will discharge and start charging when the counter resets. If 5 consecutive pulses are missed, the caps will be at 5V. This 5V will be higher than 4.9V at the comparator. Which will create the signal I need....(the rest of the circuit I have already).
So I need some ideas from the experts. Do you guys think this is a good approach? Do you have a better way of doing this?
Edit: Counter will be used to count missing pulses. The time interval will always be the same and very robust. Duty cycle is going to be 30% on and 70% off. I will have to pick the correct capacitors but it is not critical now. Frequency is 10Hz
Any feedback is appreciated.
Thanks in advance.