USB Data Voltages for Charging

Discussion in 'General Electronics Chat' started by imzack, Jan 2, 2013.

  1. imzack

    Thread Starter Active Member

    Nov 3, 2010
    50
    0
    Hello,

    I am currently working on a cell phone charger.

    I want to be able to charge Android phones as well as the Iphone.

    Andriod phones want the data pins tied together for it to take the 5volt charge from the VCC pin, otherwise if the data pins are not tied together, the phone will not charge.

    Likewise for the Iphone, The iphone wants different voltages on the data pins, if the correct voltages are not used, then the iphone will not charge.


    My question is, is there any way to make a charge that will do both? I dont want to have to resolder resistors each time i want to charge a different device.


    Any suggestions would be greatly appricated!

    Thank you
     
  2. JMac3108

    Active Member

    Aug 16, 2010
    349
    66
    If I understand what you're saying .. why not just a switch that you change depending on the phone?
     
  3. ScottWang

    Moderator

    Aug 23, 2012
    4,852
    767
    Do you want to use BJT or MOSFET to do the Switch job?
    Or you can use two limit switches to switch the powers for Android phone or Iphone.
     
  4. imzack

    Thread Starter Active Member

    Nov 3, 2010
    50
    0
    I could make another switch that controlled what phone to charge, but I was wondering if there was a better way...

    I would ideally like to just plug my phone into the usb and it automatically charge it, regardless of what type of phone it is...

    also, how would a limit switch work?


    Thanks again
     
  5. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    4,769
    969
  6. imzack

    Thread Starter Active Member

    Nov 3, 2010
    50
    0
    very nice!

    I think ive seen this before, but my question would be, do you think this would charge the other devices too, like android?

    I'm assuming so, since they were trying to get it to charge a lot of products it sounded

    Thank you, ill try there set up at the end either way and do some tests
     
  7. kubeek

    AAC Fanatic!

    Sep 20, 2005
    4,669
    804
    How about if you actually put a usb host controller inside the the charger, then any device would use it as a standrad pc usb port, wouldn´t it?
     
  8. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    4,769
    969
    pretty sure.. (don't have an iphone but brother has a Iphone 4) you can't plug an iphone into a computer USB port. It doesn't work/doesn't recognize it and won't charge.
     
  9. imzack

    Thread Starter Active Member

    Nov 3, 2010
    50
    0
    dang, I have the new iphone...

    But either way, how big is a usb host controller?

    does it cost alot?
     
  10. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    IIRC, a voltage divider of 75k from V+ and 49.9k from GND each to D+ to and D-.

    If those aren't there, the phone will say "Unauthorized Charger". Droid phones work on iPhone charger with that setup. You'll also want to make sure the power line is clean of ripple and isolated.

    Schematic of the "USB Cube' From Apple, any fewer components and it is unsafe due to lack of isolation. Required resistors shown in page 2

    Complete schematic, information, and teardown of a "USB charger Cube They are far more advanced than their size would indicate. The Chinese clones half under a dozen parts and nowhere near the filtering and protection.

    Here's a video of cheapo cube charger teardown with more information.
     
  11. vrainom

    Member

    Sep 8, 2011
    109
    19
    Hey, I just saw that video earlier today. Those designers really wipe their asses with the safety regulations. The ground and (potentially) 300 volts rails separated by a half a millimiter creepage!
     
  12. imzack

    Thread Starter Active Member

    Nov 3, 2010
    50
    0
    wow, I love this write up of the apples smps.

    Also,i think i saw that EEVBlog video on youtube as well,of the fake usb chargers...

    Im gonna read this Ken Shirriff's blog write up though, looks really cool!
     
Loading...