USB to Dual HDMI Converter (HDMI Dock)
USB3.0 to Dual 4K HDMI Output Display Dock with dual HDMI ports, high-speed USB3.0 interface, and 4-layer PCB design.
Project Description
The USB to Dual HDMI Converter is designed to connect two HDMI monitors to a PC over a single USB3.0 interface.
It serves as a USB Docking Station solution, enabling extended or mirrored displays for productivity, multimedia, and workstation applications.
This project was developed to meet the growing demand for multi-monitor setups in compact office environments, digital workstations, and mobile productivity solutions. The design focuses on delivering high-resolution display output while maintaining low CPU utilization and efficient power usage.
Working
The device is powered by the Silicon Motion SM768 USB Display Docking Station SoC, a high-performance USB graphics controller.
- The SM768 supports multiple displays up to 4K Ultra HD resolution via USB.
- Provides instant screen mirroring without driver installation.
- Offers low CPU loading, low power consumption, and CAT compression technology for high image and video quality.
HDMI Outputs:
- One direct HDMI output from SM768.
- The second HDMI output is generated using an HDMI transmitter IC (ITI66121FN), which converts SM768 TTL data into HDMI signals.
Firmware and Connectivity:
- A NAND Flash memory stores the SM768 firmware.
- The device connects to the host PC via USB3.0 Micro-B interface.
Block Diagram
PCB Design
The PCB design features a 425-pin BGA SoC (SM768) on a 4-layer impedance-controlled board.
- 100Ω impedance-controlled differential pairs for HDMI signals.
- 90Ω impedance-controlled differential pairs for USB3.0 signals.
This ensures signal integrity, high-speed data transfer, and stable 4K performance.
Special attention was given to layer stackup, return path continuity, and high-frequency signal routing to meet HDMI and USB compliance standards.
Specifications
- Video Outputs: Two HDMI 1.4
- Supported Display Resolutions:
- 4K (3840×2160) @ 30Hz
- 2K & Full HD (1920×1080) @ 60Hz
- Interface: USB3.0 Micro-B Connector
- Software Compatibility:
- Windows 7/8/10/11 (32-bit & 64-bit) + Server editions
- macOS X
- Linux (Ubuntu, RedHat, SUSE, etc.)
- Android
- Driver Requirement: No driver needed
- Additional Feature: Custom startup logo support
Applications
- Dual-monitor office productivity setups
- Portable USB docking stations for laptops and ultrabooks
- Digital signage systems with extended displays
- High-resolution multimedia playback on multiple monitors
- Engineering and design workstations requiring multi-screen output
- Conference and presentation systems with dual HDMI output
Schematic
Photos
4-Layer PCB
Top Side
Bottom Side
Video Demo
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