Two-in-four-out USB switcher + two-channel audio switch

I. Function Introduction
1. USB and Audio Dual Switching; This USB 1-to-4 hub allows for easy switching between USB devices (such as mice and keyboards) and 3.5mm audio devices when using two hosts. Switching is as simple as pressing a button.
2. USB Backflow Prevention;
3. LED Indicators on the User End;
 
II. Design Details
1. The CH440R is a simulated 4-channel single-pole double-throw switch. Two chips are used, one for USB signals and the other for audio signals, each with its corresponding LED indicator.
2. The CH334R is a 1-to-4 USB hub .
This design uses a 12MHz external crystal oscillator, and according to the manual, no load capacitor is required (pads are empty).
3. The CH213K
is a low-dropout ideal diode chip with current limiting. The chip integrates overcurrent protection, short-circuit protection, over-temperature protection, and power polarity protection modules. It is rated at 5V*0.5A and supports DC applications with a current not exceeding 1A at 5V.
 
III. Precautions
1. The downstream USB capacitors
in this design use 10uf, 22uf, and 220uf capacitors. Replace or selectively solder them according to your needs. This configuration generally does not support external hard drives and is only recommended for low-load USB devices.
Larger capacitors provide better power supply stability.
2. The audio switching circuit
has a separate digital ground and simulator ground, using USB power supply plus a ferrite bead for power.
3. This design uses components in reverse, with the component side facing down.
4. The LED indicator positions are randomly drawn; it is recommended to correct them yourself.
5. The switching button is the cheapest 5.8 * 5.8 3-pin self-locking switch available on Taobao; replace it as needed.
6. LCSC's immersion gold process and color silkscreen printing are used; if you do not want PCB layout, simply uncheck the option when ordering.
 
IV. Reference Projects
: USB Switch - Shared Keyboard and Mouse for Two Computers - JLCPCB EDA Open Source Hardware Platform (oshwhub.com)
2-in-4-out USB Switch - JLCPCB EDA Open Source Hardware Platform (oshwhub.com)
Thanks to the above contributors for their open source contributions
 
. V. Update Log
V1.1: October 26, 2024:
    Added capacitor to the USBA female port; added ferrite bead and capacitor to the power supply of the CH440R audio switcher; significantly improved EMC, reducing output ripple and audio signal interference.