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Old 10-20-2007, 12:21 AM   #16 (permalink)
am_bb8800
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Quote:
Originally Posted by rivviepop View Post
BTW - the drivers don't "trigger" the device or vice versa. When the BB is plugged in and the drivers are installed the drivers recognize a device ID (actually, I'm guessing a manufacturer ID since that's what we use on linux) and adjust the current to 500mA. If there are no drivers then the current stays at 100mA and you get that on-device popup, which an ESC key will dismiss and charge continues.
Well I disagree, I did some bench testing using a desktop supply and the Blackberry.
  • With the BB plugged in with only pins 1 & 4 connected (positive and negative) to a regulated power supply, the amp meter registered 91mA until the the lightning bolt disappeared and the current went to 0mA. The power supply i used can deliver 15A consistently if required.

  • With the BB plugged in with pins 1 & 4 connected (positive and negative) to a regulated power supply, the amp meter registered 91mA until the the lightning bolt disappeared then after you momentarily trigger pin 2 with a positive feed the current draw went to 556mA and stayed constant (without pin 2 connected "the trigger").

  • Therefore the BB unit turns on its internal charging circuit and its not the PC turning on 500mA



If you don't agree can you explain how the BB draws 91mA via pin 1 & 4 but then 556mA after pin 2 see a positive feed?

Quote:
Originally Posted by rivviepop View Post
Been thinking about this, and I think why your pin 1 - 2 bleed wiring works is that it feeds more juice to the BB out that pin (right?) and mimics the idea that the PC increased the current. I wonder what mA are coming out of it...got a meter?
The above answers yout question, no additional current is drawn via pin 2 as its only a momintery connection (for the test). As you can't easily trigger pin 2 "on the road", a bleed resistor does the next best thing without effecting the BB or PC/USB Charger.
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Last edited by am_bb8800 : 10-20-2007 at 12:26 AM.
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