Application information

HDMI2C2-14HD

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DocID024813 Rev1

In case the application is set in stand-by mode, the +5 V main supply of the application is

generally powered off in order to reduce as much as possible the global power

consumption. The CEC driver can be the only device still working in low power mode,

allowing a wake up of the whole application through the CEC line. When the main power

the HDMI2C2-14HD keeps the CEC bus working properly while all other outputs of the

component are put in high impedance mode.

The CEC output (cable side) integrates a protection against ESD which is compliant with

IEC61000-4-2 standard, level 4 (8kV contact).

2.2

DDC functional block description

The DDC bus is described in the HDMI 1.4 standard as the Display Data Channel. The

topology corresponds to an I2C bus that must be compliant with the I2C bus specification

version 2.1 (January 2000). The DDC bus is made of 2 lines: data line (SDA) and clock line

(SCL). It is used to create a point to point communication link from the source to the sink.

EEDID and HDCP protocols are flowing through this link, making this I2C communication

channel a critical element in the HDMI application.

The DDC block integrated in the HDMI2C2-14HD allows a bidirectional communication

between the cable and the ASIC. It is fully compliant with the HDMI 1.4 standard and its

CTS, but also with the I2C bus specification version 2.1. The DDC block shifts the electrical

the functional diagram of the DDC block integrated in the HDMI2C2-14HD device.

Figure 4. The DDC functional block diagram (SCL and SDA lines)

The DDC_EN allows to authorize or not a bidirectional communication through the

functional block. It can be connected to the main +5V of the board, or to the ASIC power

supply, detecting then if the application is ready for communication or not.

The DDC outputs (SCL and SDA on cable side) integrate a protection against ESD which is

compliant with IEC61000-4-2 standard, level 4 (8kV contact).

SCL_IC

SDA_IC

VDD_IC

reshaping

circuit

5V_IN

5V_IN

SCL

SDA

VDD_IC

HDMI

ASIC

+5V

DDC_EN

5V_IN

Enable

Drive

HDMI

connector

decoupling

capacitance

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