IP6821

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11.2 ASK Communication Demodulation/FSK Modulation

IP6821 has a built-in ASK demodulation module. For the ASK modulation signal from the receiving

device, IP6821 collects the coil voltage and current respectively to demodulate and decode the ASK

signal. The system implements the qi wireless charging protocol based on the ASK decoded data.

The IP6821 has a built-in FSK modulation function. Through FSK modulation, the IP6821 can send

information to the receiving device to implement PPDE and EPP protocols.

11.3 Input Fast Charging

IP6821 has built-in USB PD protocol, applying voltage to PD adapter through CC1, CC2 pins.

IP6821 has built-in DP/DM class adapter fast charging protocol, applying voltage to the adapter

through DP, DM pins.

11.4 NTC Temperature Protection

The IP6821's LED1 pin is time-multiplexed to realise the LED indicator and NTC detection function.

The recommended parameters for the NTC resistor are B=3950,100k.

The NTC detection pin of IP6821 can output 20uA constant current source, external 100k NTC

resistor, 20uA constant current source forms voltage on NTC resistor, and the internal ADC of IC detects

this voltage to achieve temperature protection. If the NTC function is not used, this pin is connected to

100K resistor to ground.

Users should follow the steps below when customising the NTC temperature protection threshold:

1、Check the datasheet of NTC resistor to find the temperature-resistance relationship table;

2、According to the protection temperature point, find the corresponding resistance value R_NTC, then

the internal ADC detects the voltage for protection threshold: VNTC = RNTC * 20μA(unit mV);

3、Use the parameters provided by the original factory to configure the host computer software, VNTC

configuration to the firmware, the new temperature protection threshold will take effect;

4、The standard firmware NTC protection threshold is set to 60 ℃ (480mV), when the NTC voltage is

detected to be lower than 480mV protection. NTC recovery threshold is set to 50 ℃ (700mV), when the

NTC voltage is detected to be higher than 700mV to resume charging.