DocID025281 Rev 1

9/23

HDMI2C1-6C1

Application information

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Figure 8. Simplified view of the electrical parameters of the HPD block

2.3.2

HEAC link

The HEAC link is described in the HDMI 1.4 standards as the HDMI ethernet and audio

return channel. It corresponds physically to one differential wired pair made of the Utility line

and the HPD line. Two signals are transmitted through this link.

The first signal corresponds to the HDMI ethernet channel (HEC). The signal is transmitted

in differential mode (bidirectional) through the HEAC link. It is specified by the 100Base-TX

IEEE 802.3 standard (fast ethernet 100Mbps over twisted pair). Therefore, the HEC

integrates an ethernet link into the video cable, enabling IP-based applications over the

HDMI cable.

The second signal corresponds to the audio return channel (ARC). The signal is transmitted

either in common mode (unidirectional, from sink to source) through the HEAC link. It is

specified by the IEC 60958-1 standard. The ARC function integrates an upstream audio

capability, simplifying the cabling of the audiovisual equipment. It is no more necessary to

use a coaxial cable from TV to audio amplifier.

The HDMI2C1-6C1 helps the designer to implement this high added value HEAC function in

the application, protecting the link against the ESD with no disturbance of the signal. It

provides 2 distinct outputs HEAC+ and HEAC in order to ease as much as possible the PCB

layout.

2.4

+5V protection and fault line

The +5 V power supply that the source device has to provide to the HDMI cable is described

by the HDMI 1.4 standard. It must be protected against accidental short circuit that could

occur on the cable side.

The HDMI2C1-6C1 device embeds a low drop current limiter. If an overcurrent is detected,

the HDMI2C1-6C1 limits the current through the +5V power supply. If the current is too high

(short circuit), the device opens the +5V.

Furthermore, the HDMI2C1-6C1 device embeds also an over temperature protection (OTP).

If the internal temperature of the device is reaching a too high value, the +5V supply is

opened in order to protect the application.

HPD_IC signal

Signal on HPD link

5V