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QI standard is: the charger produced by the manufacturer pointing to the QI, the standard clauses mentioned by the QI standard must be done strictly in accordance with the documents written on the document, and are completely processed and produced in accordance with its method and method.
QI's wireless charging communication standard
Under the wireless charging Alliance (WPC) standard, the power consumption of wireless transmission is only 0 to 5W. The system that achieves this range of standards uses inductive coupling between 2 planar coils to transmit electricity from the power transmitter to the power receiver. The distance between the original secondary coils is generally 5mm, and the output voltage regulation is responsible for a global digital control loop when the power receiver will communicate with the power transmitter and generate power. The communication is a one-way communication through the backscatter modulation from the power receiver to the power transmitter. In backscatter modulation, the power receiver adjusts the load, thereby changing the current consumption of the power transmitter. Monitor these current changes and demodulate the information needed for 2 devices to work together.
Communication protocols include analog, digital pulse (Ping), personal identification, configuration and power transmission. The typical startup sequence of the power receiver placed on the power transmitter is as follows:
1) the analog Ping from the power transmitter detects the presence of objects.
2) the digital Ping from the power transmitter is a lengthened version of the analog Ping, allowing the power receiver to have time to recover a signal strength packet. If the strength of the information packet is valid, the power transmitter will keep the coil energized and proceed to the next step.
3) in the identification and configuration phase, the power receiver sends some packets, identifies them, and provides configuration and setting information to the power transmitter.
4) during the power transmission phase, the power receiver sends the control error packet to the power transmitter to increase or decrease the power. During normal operation, the control error packet is sent at about 250ms every time and is sent every 32ms once the big signal changes. In addition, during normal operation, the power transmitter sends power packets every 5S.
5) in order to terminate the power transmission, the power receiver sends a "terminating charge" message or does not communicate within the 1.25s to make the power transmitter enter a low power state.
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