Blackberry cellphones can’t be charged with ordinary usb chargers. They have a significant logic of charging from USB. Here i will explain the charging circuit logic of mini usb for blackberry cellphones. This will help to make a blackberry charger at home. A small and working circuit describe blackberry charging logic and for normal or ordinary USB chargers or nokia to USB charger see here.
Usually blackberry has mini usb ports.The mini usb connectors has 5 pins instead of 4 like ordinary USB cable(shown in image).
The pins circuit has pin1 +5v supply pin2 and pin3 are shorted then connected with pin x(that is additional in mini usb) through a variable resistor of 10kΩ, pin4 has -5v(gnd).
NOTE: the variable resistance of 10kΩ is set to near 7kΩ. The Circuit is tested successfully with Blackberry Bold 9000