CH334F Dual Uplink Switching USB Hub

This project's functionality is similar to the previously released SL2.1A USB Hub, which supports dual uplink signal selection. Based on previous Hub user experience, the CH334F solution has been improved as follows:

Dual Uplink Switching Architecture: The original solution used two ideal diodes. Continuously switching the 5V power supply when switching devices could prevent some USB devices (such as Redmi computers and speakers) from resetting their state and establishing a connection with the new host. This time, a double-pole triple-throw switch is used. The two outer positions connect to the two computers, while the middle position disconnects the power. This simple method powers down the device when switching hosts, ensuring device reset and eliminating the need for ideal diodes. (Note: This solution no longer allows two hosts to power the Hub simultaneously, reducing power supply capacity, but it is sufficient for connecting low-power peripherals such as keyboards and mice.)
Main Control Chip: Changed from SL2.1A to CH334F. The CH334F is inexpensive, has a smaller package, supports high-performance MTT mode (4 TTs each corresponding to one port, concurrent processing), and outperforms the SL2.1A. It also supports LEDs and overcurrent detection.
The USB analog switch chip has been replaced with the RS2227, which is much cheaper and has a smaller package.
Overcurrent detection with the CH217K has been added.
Port indicator lights provided by the CH334F have been added.
Its smaller size and the addition of M2 screw holes facilitate enclosure installation.

Reference prices for major components on Taobao:

CH334F: 1.8 yuan (free shipping);
RS2227: 0.6
yuan (free shipping); CH217K: 0.5 yuan (2 yuan shipping);
SK-23D07 side-mounted double-pole triple-throw switch: 0.07 yuan (1 yuan shipping);
16-pin Type-C surface mount female connector: 0.2 yuan (1 yuan shipping)
; Metal-enclosed USB 2.0 Type-A female connector (aesthetically pleasing): 0.4 yuan (1 yuan shipping).

A single set of the above major components costs approximately 5 yuan. Other components such as resistors, capacitors, TVS diodes, and crystal oscillators are not included in the price.
Notes:

Impedance matching is designed according to 90R, and the stack-up is JLC04161H-3313 (actually, this impedance is negligible for USB 2.0).
The RS2227 pads are extremely small, and hand-brushing the SMT stencil is prone to failure. It is recommended to use solder paste and a hot air gun for soldering (personally, I think leadless packages are much easier to solder than densely pinned packages; the latter can be soldered for half an hour without cleaning).
The R8 resistor value can be adjusted according to the datasheet. Configure the CH217K current limiter.
The LED reference circuit in the CH334F datasheet is in the order of 4321 from top to bottom (I drew it backwards the first time I boarded it).
When no device is connected, the CH334F enters sleep mode, and all indicator lights are off. When a device is plugged in, the corresponding indicator light and the master control light automatically light up.
The BOM exported from LCSC EDA is correct.

Update record

2024.8.15: OVCUR# pull-up resistor added based on the reference design.

More pictures:
The background board is an IPI Cryst 75 transparent PCB keyboard.