Geekzone: technology news, blogs, forums
Guest
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.




652 posts

Ultimate Geek
+1 received by user: 163


# 208117 27-Jan-2017 11:21
Send private message

So I got the USB 5V 3A DC-DC buck converter from eBay and I've realised I don't know the polarity of contact pads. Experience has told me that the top corner is positive when looking down from the top view, but I just can't be sure. Normally the eBay seller has a diagram highlighting the parts. Any ideas?

 

Click to see full size

 

Click to see full size






View this topic in a long page with up to 500 replies per page Create new topic
 1 | 2
6615 posts

Uber Geek
+1 received by user: 2293
Inactive user


  # 1710584 27-Jan-2017 11:40
Send private message

Keen to hear back about how well they work and if it has enough grunt to charge a Samsung S6 in less than 11 hours....

 

 


2094 posts

Uber Geek
+1 received by user: 893

Trusted
Subscriber

  # 1710590 27-Jan-2017 11:50
Send private message

It looks like the top right is the positive as the big 4R7 thing is the inductor


 
 
 
 




652 posts

Ultimate Geek
+1 received by user: 163


  # 1710593 27-Jan-2017 11:53
Send private message

TimA:

 

Keen to hear back about how well they work and if it has enough grunt to charge a Samsung S6 in less than 11 hours....

 

 

 

 

I don't have a Samsung S6 to try but I do have a very fussy Raspberry Pi 3 which needs ~2.5A so I let you know my results.








652 posts

Ultimate Geek
+1 received by user: 163


  # 1710599 27-Jan-2017 11:58
Send private message

Handle9:

 

It looks like the top right is the positive as the big 4R7 thing is the inductor

 

 


FOUND IT! Phew.

 

Also mentions About Apple and Sumsung devices for the USB output.

 

Click to see full size






6615 posts

Uber Geek
+1 received by user: 2293
Inactive user


  # 1710600 27-Jan-2017 11:59
Send private message

jimbob79:

 

Handle9:

 

It looks like the top right is the positive as the big 4R7 thing is the inductor

 

 


FOUND IT! Phew.

 

Also mentions About Apple and Sumsung devices for the USB output.

 

Click to see full size

 

 

 

 

That 1.5A trickle charge, id have a flat phone before it would charge?




652 posts

Ultimate Geek
+1 received by user: 163


  # 1710891 27-Jan-2017 22:12
Send private message

Unfortunately this eBay module is not powerful enough to provide suitable power for the  Raspberry Pi 3 frown. The USB Doctor monitor show 5.1~2 volts and 0.68 amps. It's show a 'thunder bolt'  in the top right hand corner. This is not going to work for my application.

 

More info Pi3 with a lightning bolt:

 

 

 

https://www.raspberrypi.org/forums/viewtopic.php?t=82373






472 posts

Ultimate Geek
+1 received by user: 175

Subscriber

  # 1710917 27-Jan-2017 23:14
Send private message

What input voltage / source were you using?

 

I have found some of these cheep 'BUCK' regulators, the input voltage needs to be at least twice the output voltage before they start to perform correctly.




652 posts

Ultimate Geek
+1 received by user: 163


  # 1710920 27-Jan-2017 23:28
Send private message

djtOtago:

 

What input voltage / source were you using?

 

I have found some of these cheep 'BUCK' regulators, the input voltage needs to be at least twice the output voltage before they start to perform correctly.

 

 

 

 

I'm using a 12V 6A power Supply.






430 posts

Ultimate Geek
+1 received by user: 224

Trusted

  # 1711317 29-Jan-2017 14:02
Send private message

May I suggest that you try soldering a bridge across the two data pins on the USB outlet? A lot of devices will see this connetion and in turn draw more current from the supply than if they are left open.

Unfortunately Apple devices are lookng for a specific voltage across the data lines, involving a resistor bridge circuit to make work correctly, but in this case the Pi shouldn't care.

22073 posts

Uber Geek
+1 received by user: 4685

Trusted
Subscriber

  # 1711329 29-Jan-2017 14:30
Send private message

If there is 5.1v at that end of it and that low current then its not the buck converters fault. Try another cable and see how you get on.

 

 





Richard rich.ms

412 posts

Ultimate Geek
+1 received by user: 100


  # 1711414 29-Jan-2017 18:13
Send private message

Ge0rge: May I suggest that you try soldering a bridge across the two data pins on the USB outlet? A lot of devices will see this connetion and in turn draw more current from the supply than if they are left open.

Unfortunately Apple devices are lookng for a specific voltage across the data lines, involving a resistor bridge circuit to make work correctly, but in this case the Pi shouldn't care.

 

 

 

from the photo of the underside of the board they are already bridged





 The views expressed by me are not necessarily those of my employer


430 posts

Ultimate Geek
+1 received by user: 224

Trusted

  # 1711462 29-Jan-2017 19:49
Send private message

haha so they are - my bad! Why things are seen...



652 posts

Ultimate Geek
+1 received by user: 163


  # 1711464 29-Jan-2017 20:05
Send private message

After trying to charge iPhones and iPads I was unable to get over 1 amp. I'm not convinced that the buck converter is able produce current over 1 amp nor the 3 amps as advertised.






430 posts

Ultimate Geek
+1 received by user: 224

Trusted

  # 1711467 29-Jan-2017 20:14
Send private message

Depending on the model/age of the i-device, it will never draw full current as the i-device is looking for specific voltage on the data line.

I can't post links yet due to being too green, however google "adafruit minty boost" - you'll need a few resistors and a soldering iron, then you'll be able to make a circuit that will tell the i-devie that it can indeed draw the current it wants from the charger.

22073 posts

Uber Geek
+1 received by user: 4685

Trusted
Subscriber

  # 1712477 29-Jan-2017 20:54
Send private message

idevices are a prick like that. When I briefly had an ipad it would do the useless not charging thing and still go flat if you were using it on any charger that didnt have the stupid apple voltages on the pins. Last I used a friends one it seemed to charge slowly off a non apple charger so perhaps they fixed that stuffup of a design a little bit?





Richard rich.ms

 1 | 2
View this topic in a long page with up to 500 replies per page Create new topic



Twitter »

Follow us to receive Twitter updates when new discussions are posted in our forums:



Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:



Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:





News »

Video game market in New Zealand passes half billion dollar mark
Posted 24-May-2019 16:15


WLG-X festival to celebrate creativity and innovation
Posted 22-May-2019 17:53


HPE to acquire supercomputing leader Cray
Posted 20-May-2019 11:07


Techweek starting around NZ today
Posted 20-May-2019 09:52


Porirua City Council first to adopt new council software solution Datascape
Posted 15-May-2019 12:00


New survey provides insight into schools' technology challenges and plans
Posted 15-May-2019 09:30


Apple Music now available on Alexa devices in Australia and New Zealand
Posted 15-May-2019 09:11


Make a stand against cyberbullying this Pink Shirt Day
Posted 14-May-2019 20:23


Samsung first TV manufacturer to launch the Apple TV App and Airplay 2
Posted 14-May-2019 20:11


Vodafone New Zealand sold
Posted 14-May-2019 07:25


Kordia boosts cloud performance with locally-hosted Microsoft Azure ExpressRoute
Posted 8-May-2019 10:25


Microsoft Azure ExpressRoute in New Zealand opens up faster, more secure internet for Kiwi businesses
Posted 8-May-2019 09:39


Vocus Communications to deliver Microsoft Azure Cloud Solutions through Azure ExpressRoute
Posted 8-May-2019 09:25


Independent NZ feature film #statusPending to premiere during WLG-X
Posted 6-May-2019 22:13


The ultimate dog photoshoot with Nokia 9 PureView #ForgottenDogsofInstagram
Posted 6-May-2019 09:41



Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.


Support Geekzone »

Our community of supporters help make Geekzone possible. Click the button below to join them.

Support Geezone on PressPatron



Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.