Chapter 1. CLM EVB Summary

Introduction of CLM EVB

To expedite a Type-C USB port connected Device (TCD) displays its video signal to a DisplayPort™ (DP) monitor through Type-C interface, a Type-C-Link-to-DP-Monitor Evaluation Board (CLM EVB) is designed, where its functions include the Type-C Power Delivery (PD) charging, DP Alternate (Alt) mode, and USB 3.1 data streaming. The key functions of the CLM EVB is shown in the red dash line block of Figure 4, where the CLM EVB can support PD 3.1 compliant TCDs such as notebook PC, Smartphone, Desktop PC, and other mobile or non-mobile devices.

1.2 Key Features

The CLM EVB demonstrates 2 key functions: USB Type-C PD charging, and DP Alt mode support of video stream and USB 3.1 data.
To implement the PD 3.1 protocol and charging, a USB-IF compliant PD controller CY43781 is used. To support the DP Alt mode and USB data, the high speed switch PI3USB31531 and signal re-driver PI3DPX1207C are included. To deliver up to 100W of PD output power at Type-C port and provide 5V at Type-A port, the power stage uses a DC/DC buck-boost controller and a DC/DC buck converter AP63205, respectively.

1.2.1 CY43781 - USB PD Controller for Type-C Port in DP Monitor

• Type-C PD 3.1 SPR Compliance Protocol Controller
• Embedded MCU with hardwired PD protocol  supports CC1/2 detection, traffic identification and routing requirements for PD compliance charging and data flow control
• Support DFP charging up to 100W (20V @ 5A)
• Support UPF DisplayPort™-Over-Type-C™ Alternate (DP Alt) mode and USB 3.1 Gen 1 / Gen 2
• Configure I2C Slave devices to support PD charging,  video and data routing through I2C interface
• OVP,  OCP, UVP Protection

1.2.2 PI3USB31531 - Crossbar Switch for Type-C USB 3.1 Gen1 /Gen 2 / DP1.4

• Six Differential Channels to 2/4 Differential Channel Switch
• Support Pin Assignment C, D, E for Sink
• USB 3.1 Gen I 10Gbps/s (-3db) for Super Speed and     (-3.7db) Switching to USV Type-C Connector
• Multiplexes one of the following to USB Type-C
• One Lane of USB 3.1 Gen1/Gen2 Signal and Channels of  DP1.2 / DP1.4 Channels of Signal

1.2.3 PI3DPX1207C - DP-Alt DP1.4 / USB 3.1 10Gbps Re-Driver

• DP-Alt 4-channel Re-driver and De-Mux (DP 2-ch and USB 2-ch)
• DP1.4 (8.1Gpbs) and USB 3.1 Gen 2 (10 Gbps) standard compliance
• Type-D DP/USB mode selection: DP only, USB only, DP/USB split modes
• Type-C Plug and Aux Flipping control through I2C slave pins

1.3 Applications

• DRP Type-C Port Type-C Interface Model for PC Monitors, TVs and USB Hubs

1.4 Main Power Specifications

1.5 CLM EVB Picture

Chapter 2. Function Description, Schematic and BOM

2.1 Application Scenario

With emerging USB-C connectors and PD capability available, new generation of Type-C PD PC monitors can be used as both a power source and a data hub for personal and professional PC work environment. While a Type-C PD monitor is the only device plugged in wall outlet for AC power inputs, it plays as data UFP (Upstream Facing Port) to the connected to TCDs (e.g. Notebook, PAD, Phone) as well as DC power DFP (Downstream Facing Port) for the required power in the monitor. Once the DFP DC power is delivered, the monitor and the TCD swaps data role. Playing as the DFP role, the TCD requests the UFP monitor to support the DP Alt mode so that the DP video signal can go to the DP monitor properly. Figure 3 illustrates a usage set up for PC Notebook and PC monitors in typical PC working scenarios.

The Type-C PD monitor system block could be divided into four main functions:

• Power Unit (conversion of AC Power into Desired DC Power)
• Major Image Processing and Display SoC (Image formatting and scaling)
• USB hub controller (support various USB devices)
• Type-C PD Interface (dealing with PD charging and data/video signaling and routing)

The CLM EVB, Figure 4, is designed to implement the Type-C PD Interface for Type-C PD monitor.

2.2 Functional Description

The CLM EVB is designed to input a DC power of range 12V~20V, which is supplied by an AC-to-DC power conversion module board inside the Monitor with AC Power input from the AC wall outlet,  as illustrated in Figure 4. This application operates in the following modes:

• 100W DFP charging port with UFP supported for DP Alt mode
  When the USB-C port is connected to a Notebook or a Mobile Phone by an USB Type-C cable, CLM EVB sources up to 100W power for charging the Notebook or the Phone. Then CLM EVB swaps to be an UFP to support the monitor with DP Alt mode output to the DisplayPort connector, and the USB device (SSD) to the USB connector.

• Self-powered UFP supported for DP Alt mode
  When the USB-C port is connected to a Desktop PC by an USB Type-C cable, the CLM EVB acts as a self-powered UFP to support the monitor with DP Alt mode output to the DisplayPort connector, and the USB device (SSD) to the USB connector.

To support desired PD 3.1 charging and data/video signaling and routing for DP Alt mode, the CLM EVB adopt the following key components:

1. DisplayPort™-Over-Type-C Capable PD Controller (CY43781 - USB PD controller supporting DP Alt mode.)
2. I2C Buck-Boost Controller (capable to support up to 100W PD charging, 20V@5A)
3. I2C Type-C Re-driver  (PI3DPX1207C - DP-Alt DP1.4/USB3.1 10Gbps linear re-driver with non-blocking, latency-free and built-in aux switch)
4. I2C 6:4 Cross-Bar Switch (PI3USB31531 - 3.3V, Type-C™ USB3.1 Gen2/DP1.4 6:4 Crossbar Switch)
5. I2C IO Expander chip (PI4IOE5V9554 - 8-bit I2 C-Bus and SMBus I/O Port with Interrupt )

When the Type-C attachment is completed between an active CLM EVB and the NB host, the power profile negotiation begins with a series of Channel Configuration (CC) commands and response exchanges. Upon successful negotiation, the power profile selection is concluded. The CY43781 enables the attached I2C buck-boost controller to output the matched PDO (Power Data Object) power to charge the NB host.   

Once the charging is conducted, the CY43781 sends the data role swap request to the NB host. If the request is accepted, the NB host plays as DFP, and starts to request the UFP CY43781 to support the DP Alt mode. Upon successful decoding the Vendor-Defined Message (VDM) commands on the CC line driven by NB host, the CY43781 enters the DP Alt mode. The decoded information is then sent to the high speed switches and re-timer/re-driver signaling chips through the CY43781 I2C interface, so that the data stream can be delivered from the host side to the DP in the right routing path and in the correct signaling, as the green color line illustrated in Figure 4.

During the video and data inquiry process, the CY43781 identifies proper Pin Assignment (C, D, E, 2-lane/4-lane DisplayPort™, 1-lane USB3.1, 2-lane DP+1-Lane USB) to match various attached output devices (e.g. Monitor, or SSD), where it includes the routing information for the Cross-Bar Switches (e.g. PI3USB31531) and the signaling parameters for signal conditioning chip (e.g. PI3DPX1207C).  In addition to its default value, the PI3DPX1207C can be set up the crucial parameters (register values) according to PCB trace lengths (Type-C Connector to Re-Driver, Re-Driver to DP/USB port), types of incoming data/video and cable loss characteristic by the CY43781 through the I2C interface.

Considering power requirement for support various Type-C active cables, the CLM EVB has an extra power circuitry based on synchronous buck regulation (AP63205) to support more than 2.0W power. If adequate power source in the main monitor board is available to support up to 2.0W power (5V), this extra active power circuitry could be saved.

To support development-debugging purposes, the CLM EVB adopts I2C IO Expander chip (PI4IOE5V9554) to monitor critical signals shown below:

Furthermore, the CY43781 also minimizes of standby power consumption (<40mWatt, excluding I2C IO expander circuitry) of the overall CLM EVB to meet Energy Star requirements on PC monitors.