I'm having trouble seeing the current flow and understanding how the transistors are activated and deactivated so that the signal reaches the "EN" of the IC, which in turn activates the 5 V output further to the right.

Can anyone help me with this?

Thanks!

 

What does it mean to "press" the POWER_KEY? Is that node normally floating and then it is connect to something when the key is pressed? If so, what? From the size of the resistors, I'm roughly guessing that it gets connected to about 12 V when the key is pressed.

The primary purpose of that circuit appears to be providing an open-collector level shifter. The capacitors are likely providing some combination of debouncing and time delay.

 

What does it mean to "press" the POWER_KEY? Is that node normally floating and then it is connect to something when the key is pressed? If so, what? From the size of the resistors, I'm roughly guessing that it gets connected to about 12 V when the key is pressed.

The primary purpose of that circuit appears to be providing an open-collector level shifter. The capacitors are likely providing some combination of debouncing and time delay.

It seems that when the button is pressed (which is a non-permanent button, i.e., it returns to its original state when you stop pressing it), it grounds the POWER_KEY line.

It is the speaker's power circuit, and I know that when the button is pressed, something happens to those transistors, resistors, and capacitors that send a pulse to the IC that turns it on. But I can't understand how it works

 

I'm having trouble seeing the current flow and understanding how the transistors are activated and deactivated so that the signal reaches the "EN" of the IC, which in turn activates the 5 V output further to the right.

Can anyone help me with this?

Thanks!

Hi,

Q6 starts out being on, and Q5 off.
It looks like when you press the button Q6 turns off eventually and then Q5 turns on which makes EN go low.
When you release the button Q6 turns on eventually and then Q5 turns off again, which makes EN go high again.

If you want more details you should probably simulate the circuit.