Timeline for How to charge an android device with a buck converter
Current License: CC BY-SA 4.0
11 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Apr 19, 2020 at 14:01 | comment | added | php_nub_qq | @MattYoung I also suspected that so I switched the supply to an old pc psu and got 5v off of there just to test, still the same thing | |
| Apr 19, 2020 at 13:59 | comment | added | Matt Young | @php You really need to get your hands on a score scope and look at 5V through this. It sounds like the buck converter is dropping out but there's no way to do much more without getting the full picture of what's going on. | |
| Apr 19, 2020 at 7:31 | comment | added | php_nub_qq | @MattYoung I was too hoping that was the case so I triple checked it and it is not :( I also checked the charger that I have that the phone is happily charging with and it seems to have the data pins shorted with no resistance, I'm really confused at this point. | |
| Apr 19, 2020 at 1:30 | comment | added | Matt Young | @php_nub_qq Based on your description, it's probably wired backwards. | |
| Apr 18, 2020 at 17:33 | comment | added | php_nub_qq | Something else I observe, if I turn off the power supply while everything is connected the flow reverses and there are 80mA going to my buck converter which has an LED and it keeps glowing. When I turn the supply back on current comes back to 0. I also notice that no matter how many times I do that the screen does not go black. It appears to do so only when physically connecting the micro usb. Also I tried increasing the voltage up to 5.25 and I saw that there are 125mA flowing to the phone but there was no indication that the battery is charging which smells like trouble to me so I seized it. | |
| Apr 18, 2020 at 17:07 | comment | added | php_nub_qq | I also shorted the data pins and the screen no longer turns off. It starts charging for a fraction of a second and then stops, after trying this about 5 times it reverted to the old behavior. | |
| Apr 18, 2020 at 16:51 | comment | added | php_nub_qq | I just measured it. Unfortunately I dont have an oscilloscope to give more detailed information though. My multimeter reads 1.45A for like half a second or something and then the screen turns black as described and there is no longer current flowing | |
| Apr 18, 2020 at 15:03 | comment | added | Matt Young | @php_nub_qq The buck converter rating is irrelevant. The charge current is controlled by a battery management IC, or possibly the main SOC depending on the phone. Regardless, this all happens inside the phone and you can't control it other than emulating whatever behavior is expected on the data pins. | |
| Apr 18, 2020 at 15:03 | comment | added | Justme | The phone does not know it can draw over 100mA even if you are able to provide 10A. Unless you do something with the data pins so it knows it can draw more. | |
| Apr 18, 2020 at 14:57 | comment | added | php_nub_qq | What is a possible reason for that? Its a 3A (rated, more like 1.5A) buck converter and there is nothing else connected. | |
| Apr 18, 2020 at 14:43 | history | answered | Matt Young | CC BY-SA 4.0 |