Simple QC3.0 decoy

First, I'll post a close-up of the working status.
 
This work is a QC3.0 decoy based on CH444G. No programming is required, and multiple gears can be decoyed, or QC3.0 voltage regulation can be performed.
There are three buttons on the front: RST K2 K1, and three indicator lights on the back: QC PW HV.
PW is the power indicator.
QC is a delayed start indicator. After RST is pressed or power is turned on for a period of time, the QC indicator light will turn from dark to bright. Wait for about one second. If the power bank/charging head supports the QC protocol, it will enter the QC mode.
HV is a high-voltage indicator light, and the degree of brightness depends on the value of D4 (the voltage regulator diode on the back).
 
The button usage is as follows:
At any time, press the RST button to restart the circuit and reset the voltage to 5V.
Before the QC light turns on:
    If you do not press anything, you can enter the QC3.0 voltage regulation state with a 5V voltage after the QC handshake is successful;
    press K1 to immediately boost the voltage to 12V after the
    QC handshake is successful (QC2.0, and requires power bank support); press K2 to immediately boost the voltage to 20V after the QC handshake is successful (QC2.0, and requires power bank support);
    press K1 and K2 at the same time to immediately boost the voltage to 9V after the QC handshake is successful (QC2.0, and requires power bank support);
    release the pressed buttons after the handshake is successful, and enter the QC3.0 voltage regulation state with the current voltage (it cannot be used stably at the 9V gear because it is difficult for a person to release K1 and K2 at the same time).
In the QC3.0 voltage regulation state after the handshake is successful:
    short press K1 to reduce the voltage by 0.2V;
    short press K2 to increase the voltage by 0.2V.
Other operations not mentioned are untested operations and may cause adverse consequences.
 
This work can be changed into a QC2.0 fixed voltage decoy. Just follow the instructions to directly connect the pads of the buttons with flying wires, that is,
if a constant 9V voltage is required, short-circuit K1 and K2 with flying wires; (do not connect the two buttons together, but connect the pads of the same button)
If a constant 12V voltage is required, only short-circuit K1 and leave K2 vacant;
if a constant 20V voltage is required, only short-circuit K2 and leave K1 vacant.
If you try not to lift the two buttons K1 and K2 at the same time, you can always maintain the QC2.0 state.
 
This work reserves an overvoltage protection circuit (that is, the AO3400 series circuit on the front). If there is no such requirement, you can not weld the MOS (and the voltage regulator on the front), as shown in the figure above.
 
Due to the limited conditions at hand, the author cannot conduct a more comprehensive test. If you find any problems, please give us feedback in time. Thank you.