Timeline for Attiny85 route vcc though output pin
Current License: CC BY-SA 4.0
14 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jun 19, 2018 at 18:02 | comment | added | miccet | Perfect! Thank you so much for your help! | |
| Jun 19, 2018 at 17:44 | comment | added | Majenko | No, it won't. The gate is like a capacitor. Once charged nothing more flows. | |
| Jun 19, 2018 at 17:42 | comment | added | miccet | Just curious, would keeping the p channel mosfet gate high in this circuit even with the resistor draw current (obviously yes, but pretty low) while an n channel would not draw any current at all while the circuit is open and gate pulled low? I’m using batteries in this project so every uA is precious. | |
| May 7, 2018 at 21:45 | comment | added | Majenko | That's pretty good, yes. The voltages are relative to source, and the source is the highest potential in a P fet, so everything is below it. | |
| May 7, 2018 at 21:42 | comment | added | miccet | Would this one be a good choice? I'd rather have one with pins like a "normal" transistor, but it doesn't matter that much. Why are the voltages negative? onsemi.com/pub/Collateral/FDN302P-D.PDF | |
| May 7, 2018 at 21:40 | vote | accept | miccet | ||
| May 7, 2018 at 20:00 | comment | added | Majenko | Yep, LOW is "on", and "INPUT" or "HIGH" are off. | |
| May 7, 2018 at 19:58 | comment | added | miccet | Oh now I understand! Thank you so much. Will digitalWrite(pin, LOW) "pull the gate down"? Guess the only thing to look for now is one that has a volt range within 3.3V and try it out! | |
| May 7, 2018 at 19:35 | comment | added | Majenko | It needs a voltage. No (or miniscule) current though. The gate is like a capacitor. Once charged it doesn't draw anything to speak of - only tiny leakage current too small to measure. | |
| May 7, 2018 at 19:32 | comment | added | miccet | In my case VCC will be 3.3V and since GPIO is also from the same power source it will also be 3.3V. Also, once the circuit is cut off from power, I would like to put the attiny85 in sleep mode and not use any power for a while. If I understand this correctly, a P-channel MOSFET needs power to cut the power, is that correct? With this in mind, is this component still the one I want? Sorry, I might not have explained this very well in my question. | |
| May 7, 2018 at 19:20 | comment | added | Majenko | That is good. That is really all you need to do. | |
| May 7, 2018 at 19:09 | comment | added | miccet | I will try to find one that suits my needs and try it out. Regarding the tx/rx lines I set them both to LOW and INPUT before cutting the power. Would that be enough or will the above still be an issue? | |
| May 7, 2018 at 18:39 | comment | added | CrossRoads | Might need transistors between the Aduino and the ESP8266 to break the Rx/Tx lines. Otherwise they could go higher (due to the USB interface on the Arduino, which is connected to D0/D) then the ESP8266's VCC pin and could damage the diode clamp's on the ESP8266 inputs, or possibly appear to phantom power it. | |
| May 7, 2018 at 14:27 | history | answered | Majenko | CC BY-SA 4.0 |