22.5W power bank bidirectional fast charging power module circuit board 5-port DIY motherboard kit QC4+PD3.0. 

Protections:
Input over-voltage protection
Charging overtime / over-voltage protection
Output over-current / short-circuit protection
Temperature protection

Recommended Parameters:
Parameters Symbol MIN Typical MAX UNIT
Input Voltage VBUSB/VBUSC/VBUSL 4.5 – 13.5 V
Battery Voltage BAT 2.8 – 4.5 V
Operating Temp. -20 – +60 °C


The charging current is divided into three stages: trickle mode, constant current mode, and constant voltage mode.
When the battery voltage is lower than 3V, the charging module operates in trickle mode with a charging current of 300mA.
When the battery voltage exceeds 3V, the charging module switches to constant current mode. In this mode, it charges at the set fast-charging current, with a maximum power of 21W.
When the battery voltage rises to the target voltage (e.g., 4.2V), the charging module switches to constant voltage mode. Here, the charging current gradually decreases while the battery voltage remains unchanged.
When the charging current decreases to the cut-off level, charging stops.
After full charge, if the battery voltage drops more than 0.1V below the target voltage, charging will automatically restart.


Note:
A battery voltage higher than 4.2V is abnormal and indicates a faulty battery.
A voltage of exactly 4.2V does not mean full charge—the light indicator flashing at 4.2V means it’s still charging; full charge is reached when the current drops to the termination level.


The main board has five USB ports:
Type-A1, Type-A2, Micro-B, Type-C, Lightning
Type-A1 and Type-A2 support: QC3.0 / QC2.0 / AFC / FCP / SCP / PE2.0 / PE1.1 / SFCP fast charging output.
Type-C supports: PPS / PD3.0 / PD2.0 / QC4+ / QC3.0 / QC2.0 / AFC / FCP / SCP / PE2.0 / PE1.1 / SFCP fast charging output, and supports PD3.0 / PD2.0.