Hi all,
Really appreciate if someone can explain why is this not working as I want it to.
I need to create a simple delay using RC time delay and MOSFET to switch things on after say 1 second.
I am using sim to see if it works properly, but it gives me very slow rise time. I want it to do instant switch to hi (>2.4V) after 1 second.
Thanks for help!
Really appreciate if someone can explain why is this not working as I want it to.
I need to create a simple delay using RC time delay and MOSFET to switch things on after say 1 second.
I am using sim to see if it works properly, but it gives me very slow rise time. I want it to do instant switch to hi (>2.4V) after 1 second.
Thanks for help!
Attachments
H
HAYK
Nice! Two of those with different resistor values will allow for nice STBY and MUTE functions for TDA7293
Attached is a complete solution.
Simulation turns on voltage at 1s and then rises another 1s and stays on for 5s. Fall time is 5s.
You can see that there is about 1s delay before STBY is pulled high, and after another 1s MUTE is pulled high too.
I wonder if discharge diodes are needed?
as there are resistors in series with ground and capacitance is not as large...
Simulation turns on voltage at 1s and then rises another 1s and stays on for 5s. Fall time is 5s.
You can see that there is about 1s delay before STBY is pulled high, and after another 1s MUTE is pulled high too.
I wonder if discharge diodes are needed?
as there are resistors in series with ground and capacitance is not as large...
Attachments
So I had a chance to breadboard this circuit and it doesn’t work as intended - for TDA7293 mute and standby.
The delay is working fine.
I increased the value of the cap to 10uF and I have to wait for about two seconds for STBY signal to go from 0V to 32V. MUTE signal takes about four seconds.
On power on I still get a click in the speaker. In particular from applying voltage to the STBY pin. I tried lowering the voltage by using 10k resistor and 7.5V Zener but it didn’t help. Still a click after the time delay. I also tried not to apply MUTE signal at all. Didn’t help with the click.
On power off I get some DC spike as I see the woofer of the test speaker going in and out. So maybe there is a way to pull STBY signal to 0V right after the power is turned off…
Will be thankful if anyone has some ideas on what to try next 😁👍
The delay is working fine.
I increased the value of the cap to 10uF and I have to wait for about two seconds for STBY signal to go from 0V to 32V. MUTE signal takes about four seconds.
On power on I still get a click in the speaker. In particular from applying voltage to the STBY pin. I tried lowering the voltage by using 10k resistor and 7.5V Zener but it didn’t help. Still a click after the time delay. I also tried not to apply MUTE signal at all. Didn’t help with the click.
On power off I get some DC spike as I see the woofer of the test speaker going in and out. So maybe there is a way to pull STBY signal to 0V right after the power is turned off…
Will be thankful if anyone has some ideas on what to try next 😁👍