Timeline for Switching between battery and USB using diode OR logic
Current License: CC BY-SA 3.0
12 events
| when toggle format | what | by | license | comment | |
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| Jul 4, 2017 at 22:55 | comment | added | Jon Watte | I don't like that the battery is constantly drained with a 20 kOhm load. This will run it down pretty quickly, even when the Pi is off! The original diode option is actually better, and if you add an opamp/comparator at the anode of each diode, and use a red/green dual-direction LED, you'll get what you want with less drain and fewer parts. | |
| Oct 5, 2014 at 6:57 | comment | added | Kanishka Ganguly | thanks a lot for taking the trouble to answer the question in such detail. :D I am still working on building the circuit. Getting the parts is taking time, since we have a public holiday here in India. | |
| Oct 2, 2014 at 7:48 | history | edited | Logic Knight | CC BY-SA 3.0 |
deleted 21 characters in body
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| Oct 2, 2014 at 7:44 | comment | added | Logic Knight | @KanishkaGanguly The circuit in the BMP image is a bit confusing, but the double MOSFET idea looked interesting. After checking a few other sources, I could see how it works. I have changed my circuit above. This solves a problem I have got too. Thanks for asking the question. | |
| Oct 2, 2014 at 7:40 | history | edited | Logic Knight | CC BY-SA 3.0 |
Removed blocking diode. Added second MOSFET with explanation.
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| Sep 28, 2014 at 20:26 | history | edited | Logic Knight | CC BY-SA 3.0 |
Added diode to block reverse current flow
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| Sep 28, 2014 at 15:47 | comment | added | Kanishka Ganguly | I am going to try out your version and see the results. Also, check this out. This seems far more stable, IMHO. | |
| Sep 27, 2014 at 13:35 | history | edited | Logic Knight | CC BY-SA 3.0 |
Added more details to the design
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| Sep 27, 2014 at 13:12 | comment | added | Logic Knight | A comparator is very sensitive. As soon as Vin drops to 1 microvolt below Vbat, the MOSFET will turn on and smoothly take over the supply of current to the Pi. | |
| Sep 27, 2014 at 12:23 | comment | added | Kanishka Ganguly | I like this solution. Quite simple to make. Although, what might happen if both my USB and battery are almost the same voltage? (as mentioned in question) Will the comparator recognize such a minute difference in voltage? | |
| Sep 27, 2014 at 12:11 | vote | accept | Kanishka Ganguly | ||
| Sep 27, 2014 at 8:28 | history | answered | Logic Knight | CC BY-SA 3.0 |
