- Jan 08, 2018 -
High pass QC2.0 handshake protocol:
The fast charger is communicated with the mobile phone by loading voltage over the middle two line (D+D-) of the micro USB interface to adjust the output voltage of the QC2.0. The handshake process is as follows: when the charger terminal is connected to the cell phone through data line, the charger acquirets D+D- short through MOS, and the charger type is DCP (private charging port mode). At this time the output voltage is 5V, and the cell phone is charged normally. If the mobile phone supports the QC2.0 fast charging protocol, the HVDCP process in the Android user space will start and start loading the 0.325V voltage on the D+. When the maintenance of 1.5s voltage, short circuit charger will disconnect the D+ and D-, D- voltage will decrease; mobile phone end detects the voltage on D- decreased after HVDCP access to mobile phone charger voltage preset value, such as 9V, set the D+ voltage on 3.3V, D- on the voltage is 0.6V. The charger output voltage 9V.