help with dc/dc step up

Discussion in 'General Electronics Chat' started by bisctboy, May 29, 2009.

  1. bisctboy

    Thread Starter Member

    Nov 3, 2008
    26
    0
    I have set up a mintyboost clone and it show my ipod is charging. However, when I pull it off my mintyboost clone an hour later, the ipod shows absolutely no charge at all. Its almost like there is no current going through at all. Has anyone encountered this?
     
  2. StayatHomeElectronics

    Well-Known Member

    Sep 25, 2008
    864
    40
    Can you post a schematic of what you are doing? Did you copy the MintyBoost exactly as it was originally built?

    Does it provide a constant voltage to the iPod throughout the charging process? What is the voltage when the iPod is connected? Did you use new batteries?
     
  3. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    Maybe iPods have an internal battery charger controller and you need to provide a voltage greater than the battery's voltage.

    Just make a research and then try it because you may destroy the iPod.
     
  4. bisctboy

    Thread Starter Member

    Nov 3, 2008
    26
    0
    Yes...it is attached

    The voltage moves between 5.03v and 5.04v. It mostly stays at 5.04v. I have noticed that every so often it goes well below 5v to about 4.7v with the ipod attached. Yes, I did use new batteries and my multimeter shows the output without a load at 2.8v and 3.9amps.

    Thanks for your help!
     
  5. bisctboy

    Thread Starter Member

    Nov 3, 2008
    26
    0
    Here's the schematic I forgot to attach...

    Thanks,
     
  6. StayatHomeElectronics

    Well-Known Member

    Sep 25, 2008
    864
    40
  7. bisctboy

    Thread Starter Member

    Nov 3, 2008
    26
    0
    I found the problem...It seems that ipods require some additional work on pins 2 and 3 from my USB connector. Per the schematic I used, nothing was needed on those pins coming from my circuit. After further investigation and research I found that most ipods require that my charger trick them into thinking something is connected to pins 2 and 3 in order for it to accept a charge. I accomplished this by connecting them together along with 2 resistors. One resistor is going to ground and the other is going to power. Bingo! My ipod is charging quickly now!
     
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