USB power supply EasyVolts?? - Page 1
Forum section: electronics / projects

author: ahha7
author_rank: Newbie
timestamp: May 31, 2017, 10:46:38 am
content: Hi all,I've been thinking about using USB power to supply my projects, but I always was thinking about some cheap chinese dc-dc which seems to be interesting but inconvenient ( voltage adjustment with a screwdriver is not convenient if you often need different voltages). But yesterday I found EasyVolts project on IndieGoGohttps://www.indiegogo.com/projects/easyvolts-usb-powered-and-controlled-power-supply#/. They tell that it can provide 0-15V with up to 1A. It sounds too good to be true, what do you think?.

author: fourtytwo42
author_rank: Super Contributor
timestamp: May 31, 2017, 10:59:43 am
content: Quote from: ahha7 on May 31, 2017, 10:46:38 amPartly, given the maximum power you can pull from USB (500mW anyone ? ) the output power cannot exceed this so 1A at 500mV, not so useful, at 15V you get 33mA.

author: sleemanj
author_rank: Super Contributor
timestamp: May 31, 2017, 11:02:37 am
content: Quote from: fourtytwo42 on May 31, 2017, 10:59:43 am500mA is usually regarded as the maximum current from an otherwise unspecified USB socket, that's 2.5W, not 500mW.This device further limits it to 2.25W output, at 15v after losses you're looking around 110mAAs for the utility of such a device.... eh, not for me.Just get an LM2577 based SEPIC module for a few dollars, replace the pot with a 10 turn panel one, and wire an old 2A usb power supply on it.

author: ahha7
author_rank: Newbie
timestamp: May 31, 2017, 11:14:55 am
content: Quote from: sleemanj on May 31, 2017, 11:02:37 amThanks! It's a really cool idea!

author: bktemp
author_rank: Super Contributor
timestamp: May 31, 2017, 11:32:44 am
content: The idea of a USB power supply is ok, there might be some cases where it can be useful. But it is too expensive. $45 for a 2W power supply is too much, especially without any actual specifications available.It seems to be a single chip doing all the USB communication + SMPS control. So is the regulation done in software? Does it have a input current/power limiting function?

author: ahha7
author_rank: Newbie
timestamp: May 31, 2017, 12:23:36 pm
content: IMHO price seems to be ok because it includes free shipping, but I agree that it's not cheap. "So is the regulation done in software?" - have no idea"Does it have a input current/power limiting function?" - in video they tell that output current limit can be set, may be it's used also to prevent USB overload...

author: DBecker
author_rank: Frequent Contributor
timestamp: May 31, 2017, 08:22:07 pm
content: I think that they are over-marketing this as a the "first USB.. power supply".There are several USB devices I know of that provide software-configurable step-down power output incidental to other functions.I can't think of any offhand that are step-up converters, but they likely exist.This would be a more interesting device if it provided accurate voltage, current and power limiting+monitoring, both instantaneously and averaged. With both coulomb counting and total energy tracking it would be useful for analyzing power use or characterizing batteries.

author: ahha7
author_rank: Newbie
timestamp: May 31, 2017, 08:42:44 pm
content: Hi DBecker, although in the video from Indiegogo they say it measures power and voltage simultaneously and continuously, I don't think that it's useful for battery characterisation because power of the device is quite small. Also I'd be happy to know about other similar devices especially if they are cheaper )) Please share a link if you have one for a similar device.

author: ahha7
author_rank: Newbie
timestamp: November 09, 2017, 02:24:31 pm
content: Hi all,I know that this topic is quite old but I think somebody can be interested in new information about USB-dongle regulated power supply EasyVolts. Its author continues development despite not successful crowdfunding campaign. And it seems like the device gets new cool features like up to 24v output, pwm, gpio and even i2c master controlled by PC! Furthermore, complete sources of the first version of EasyVolts are published on Github! For more details check this linkwww.easyvolts.com