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Yay, another chance to show off my USB knowledge!
Basically the reason has to do with the specifications of the USB protocal. A unit load is defined as 100 mA in USB 2.0. A maximum of 5 unit loads (500 mA) can be drawn from a port in USB 2.0 There are two types of devices: low-power and high-power. Low-power devices draw at most 1 unit load, high-power devices draw the maximum number of unit loads supported by the standard. Your blackberry is a high power device, and therefore should be drawing a maximum of 500 mA.
However, with the Battery Charging Specification, new powering modes are added to the USB specification. A host or hub charger can supply maximum 1.5 A when communicating at low-speed or full-speed, maximum 900 mA when communicating at hi-speed, no upper current limit when no communication is taking place. A dedicated charger can supply maximum 1.8 A of current. A portable device can draw up to 1.8 A from a dedicated charger. The dedicated charger shorts the D+ and D- pins with a resistance of 200Ω, disabling data transfer and allowing the charger to be detected. This allows very simple, high current chargers to be manufactured.
So basically when your phone is connected to your computer, it is operating in "communication mode", and can only draw 500 mA. When attached to a wall charger, it is in "charging mode" and can draw the full 1.5 A.09-23-09 03:20 PM - A complete answer, that's what cb users ask for!Yay, another chance to show off my USB knowledge!
Basically the reason has to do with the specifications of the USB protocal. A unit load is defined as 100 mA in USB 2.0. A maximum of 5 unit loads (500 mA) can be drawn from a port in USB 2.0 There are two types of devices: low-power and high-power. Low-power devices draw at most 1 unit load, high-power devices draw the maximum number of unit loads supported by the standard. Your blackberry is a high power device, and therefore should be drawing a maximum of 500 mA.
However, with the Battery Charging Specification, new powering modes are added to the USB specification. A host or hub charger can supply maximum 1.5 A when communicating at low-speed or full-speed, maximum 900 mA when communicating at hi-speed, no upper current limit when no communication is taking place. A dedicated charger can supply maximum 1.8 A of current. A portable device can draw up to 1.8 A from a dedicated charger. The dedicated charger shorts the D+ and D- pins with a resistance of 200?, disabling data transfer and allowing the charger to be detected. This allows very simple, high current chargers to be manufactured.
So basically when your phone is connected to your computer, it is operating in "communication mode", and can only draw 500 mA. When attached to a wall charger, it is in "charging mode" and can draw the full 1.5 A.
Thank you very much!
Posted from my CrackBerry at wapforums.crackberry.com09-23-09 03:23 PM - Hey...that's what I was gonna say...just kiddingYay, another chance to show off my USB knowledge!
Basically the reason has to do with the specifications of the USB protocal. A unit load is defined as 100 mA in USB 2.0. A maximum of 5 unit loads (500 mA) can be drawn from a port in USB 2.0 There are two types of devices: low-power and high-power. Low-power devices draw at most 1 unit load, high-power devices draw the maximum number of unit loads supported by the standard. Your blackberry is a high power device, and therefore should be drawing a maximum of 500 mA.
However, with the Battery Charging Specification, new powering modes are added to the USB specification. A host or hub charger can supply maximum 1.5 A when communicating at low-speed or full-speed, maximum 900 mA when communicating at hi-speed, no upper current limit when no communication is taking place. A dedicated charger can supply maximum 1.8 A of current. A portable device can draw up to 1.8 A from a dedicated charger. The dedicated charger shorts the D+ and D- pins with a resistance of 200Ω, disabling data transfer and allowing the charger to be detected. This allows very simple, high current chargers to be manufactured.
So basically when your phone is connected to your computer, it is operating in "communication mode", and can only draw 500 mA. When attached to a wall charger, it is in "charging mode" and can draw the full 1.5 A.09-23-09 06:11 PM - Yay, another chance to show off my USB knowledge!
Basically the reason has to do with the specifications of the USB protocal. A unit load is defined as 100 mA in USB 2.0. A maximum of 5 unit loads (500 mA) can be drawn from a port in USB 2.0 There are two types of devices: low-power and high-power. Low-power devices draw at most 1 unit load, high-power devices draw the maximum number of unit loads supported by the standard. Your blackberry is a high power device, and therefore should be drawing a maximum of 500 mA.
However, with the Battery Charging Specification, new powering modes are added to the USB specification. A host or hub charger can supply maximum 1.5 A when communicating at low-speed or full-speed, maximum 900 mA when communicating at hi-speed, no upper current limit when no communication is taking place. A dedicated charger can supply maximum 1.8 A of current. A portable device can draw up to 1.8 A from a dedicated charger. The dedicated charger shorts the D+ and D- pins with a resistance of 200Ω, disabling data transfer and allowing the charger to be detected. This allows very simple, high current chargers to be manufactured.
So basically when your phone is connected to your computer, it is operating in "communication mode", and can only draw 500 mA. When attached to a wall charger, it is in "charging mode" and can draw the full 1.5 A.
thanks for the info put's it into better perspective now.09-23-09 06:30 PM - Heck, everybody knows THAT.Yay, another chance to show off my USB knowledge!
Basically the reason has to do with the specifications of the USB protocal. A unit load is defined as 100 mA in USB 2.0. A maximum of 5 unit loads (500 mA) can be drawn from a port in USB 2.0 There are two types of devices: low-power and high-power. Low-power devices draw at most 1 unit load, high-power devices draw the maximum number of unit loads supported by the standard. Your blackberry is a high power device, and therefore should be drawing a maximum of 500 mA.
However, with the Battery Charging Specification, new powering modes are added to the USB specification. A host or hub charger can supply maximum 1.5 A when communicating at low-speed or full-speed, maximum 900 mA when communicating at hi-speed, no upper current limit when no communication is taking place. A dedicated charger can supply maximum 1.8 A of current. A portable device can draw up to 1.8 A from a dedicated charger. The dedicated charger shorts the D+ and D- pins with a resistance of 200Ω, disabling data transfer and allowing the charger to be detected. This allows very simple, high current chargers to be manufactured.
So basically when your phone is connected to your computer, it is operating in "communication mode", and can only draw 500 mA. When attached to a wall charger, it is in "charging mode" and can draw the full 1.5 A.
09-23-09 10:37 PM
