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5v UPS
#24
(2017-11-19, 11:13 PM)tocan Wrote: https://youtu.be/m20o3P-S5s8

Although this works, it is not a very robust design:
- Since the capacitor is connected directly on the USB voltage, they are only 4.5 V when he initiates shutdown, and he looses 19 % of the energy.
- He has no boost regulator, so he looses even more energy.
- He does not have any current limit on the charging, which can lead to stress on the supply and the capacitor, reducing the lifetime of both. A simple resistor or a one transistor constant current source would be enough.
- USB power supplies have often 5.5 V to 6 V no-load voltage, and he does not have any over voltage protection.
- He has no voltage balancing, which will reduce the lifetime. An opamp can be used for this.
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Messages In This Thread
5v UPS - by PaddyB - 2017-11-12, 08:46 PM
RE: 5v UPS - by shipahoy - 2017-11-13, 08:55 AM
RE: 5v UPS - by PaddyB - 2017-11-13, 10:44 AM
RE: 5v UPS - by shark24 - 2017-11-13, 02:06 PM
RE: 5v UPS - by abarrow - 2017-11-14, 03:31 PM
RE: 5v UPS - by shipahoy - 2017-11-13, 08:35 PM
RE: 5v UPS - by shark24 - 2017-11-13, 09:16 PM
RE: 5v UPS - by abarrow - 2017-11-13, 10:17 PM
RE: 5v UPS - by shark24 - 2017-11-13, 11:03 PM
RE: 5v UPS - by JD1 - 2017-11-13, 11:16 PM
RE: 5v UPS - by shark24 - 2017-11-13, 11:33 PM
RE: 5v UPS - by abarrow - 2017-11-14, 12:31 AM
RE: 5v UPS - by shark24 - 2017-11-14, 03:40 PM
5v UPS - by tocan - 2017-11-14, 05:37 PM
RE: 5v UPS - by shark24 - 2017-11-15, 09:40 AM
RE: 5v UPS - by tocan - 2017-11-16, 02:19 AM
RE: 5v UPS - by abarrow - 2017-11-18, 03:09 PM
RE: 5v UPS - by shark24 - 2017-11-18, 08:19 PM
RE: 5v UPS - by Sailoog - 2017-11-19, 01:30 PM
RE: 5v UPS - by shipahoy - 2017-11-19, 03:43 PM
RE: 5v UPS - by JD1 - 2017-11-19, 04:36 PM
RE: 5v UPS - by shipahoy - 2017-11-19, 07:52 PM
RE: 5v UPS - by tocan - 2017-11-19, 11:13 PM
RE: 5v UPS - by shipahoy - 2017-11-20, 03:46 PM
RE: 5v UPS - by shark24 - 2017-11-20, 04:23 PM
RE: 5v UPS - by shipahoy - 2017-11-20, 04:39 PM
RE: 5v UPS - by tocan - 2017-11-20, 08:31 PM
RE: 5v UPS - by marko_st - 2018-01-28, 06:27 AM
RE: 5v UPS - by SkipperEarly - 2018-02-02, 05:45 AM
VNC on iPad. - by marko_st - 2018-02-02, 04:58 PM
RE: 5v UPS - by Sailoog - 2018-02-05, 09:21 PM

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