CD4049 switching failing to switch

[wuemura]

Hello guys!

I'm using a CD4049 to make the CD4053 switch change, so you can hold the CD4053 switch position when you turn the circuit on, but some times fail and i have to press the switch button a few times and looks like is not precise, schematic bellow.

I have made a few other types of circuits to make the CD4053 change position, but none of then can make the CD4053 keep the last position, one of this circuits i used is the 555 and is very simple, it can be used also to test the CD4053.

Any ideas on how to make the CD4049 to be more precise?

Thanks.

View attachment 40034

View attachment 40035

 

[audioguru2]

Your 4049 circuit doesn't have a pushbutton.
Its output doesn't connect to anything.
I know that if a pushbutton is connected to J2 then the output will alternate each time the button is pressed. Is that how you have it?

Your 555 has its pin 2 and pin 6 biased at half the supply voltage. Why?
There are connectors all over the place connecting to nothing.

I don't see what the 4049 circuit connects to.

I don't see any power-up-reset so the circuit's operating state will be random when it is turned on.

 

[wuemura]

Hi Audioguru,

The push button is connected at J2, yes is what i have, but the output not always alternate it fails many times. The output of 4049 is connected directly to pin 9/10/11 of CD4053.

The 555 circuit is just a test for the CD4053... but for my needs it not work because the 4053 resets every time you disconnect the battery.

Responding to your question, with R1/R2 you bias the threshold, when the voltage at the threshold is 2/3 the 555 output is put at low level. The output goes to high level when the voltage at the trigger is lower than 1/3, C2/R3 has the same level as the output so when you press the push button (J2 connector) the level changes.

C1 defines the startup level (JP1), ground C1 to get low level at the startup or connect C1 to VCC to start with hight level.

 

[audioguru2]

Hi Wellington,
The output current of the CD4049 is not symmetrical. It sinks a lot more current than it sources. I would use a CD4069 hex inverter that has a perfectly symmetrical output current.

The value of R24 should be much lower than the value of R23 for the alternate-action circuit to be reliable. This one works well.

The supply current for a CD4053 is just about zero so why don't you leave it powered then it will "remember" its setting?

View attachment 40038

 

[wuemura]

Hi Audioguru,

Thank you for your help, i will try the 4069 instead.
About the 4053, imagine a audio selector with many inputs and every time you turn on your system you enjoy listen to the LP connected at input number 6, i think is more confortable if the device keep it's settings so you don't need to push the select button six times every time you turn it on.

To make it "remember" is a good challenge, don't you think? ;D

 

[audioguru2]

To make it "remember" is a good challenge, don't you think? ;D

I must be getting old because my car radio remembers more about what my wife likes than I can remember. ;D

 

[wuemura]

Hahahahahahaha.

I have a Palm that does this for me, to remember my wife birthday and stuff ;D ;D