Closed samchoy88 closed 9 years ago
My only concern is pullup resistor on PWR_ONOFF is drawing 0.33 mA while the device is on. I suppose that's not a very large number. What is maximum practical value of that pullup resistor?
Here's what the power on sequence looks.
A B Y
H H L <-- SW_PWR is not pressed, device is off. Device if off.
H L H <-- SW_PWR is pressed, device is off. User presses and holds the power button.
L L H <-- SW_PWR is pressed, device is on. Device boots up and enables power. User is still holding power button.
L H H <-- SW_PWR is not pressed, device is on. User releases power button.
I think it can be 100K for pull up, as it only connect a logic which has high input impedance.
Cool. Let's make that change in Electronics version 0.10.
Done. Closing issue.
I would like to implement the following soft power circuit and solve below issue:
I choose NAND gate instead of OR gate and made all input pulled up by 10K resistor.![image](https://cloud.githubusercontent.com/assets/1327611/5675401/3b0cf754-97f8-11e4-985b-447b44c9f73a.png)