Table 8: HDMI/DVI Signals
2.5.2 Reference Schematics
2.5.2.1 DVI Schematic Example
There are different configurations of DVI connectors available. The DVI-D (digital) contains only the
native DVI signals. The DVI-A (analog) provides no DVI signals. Only the analog VGA signals are
provided. The DVI-I (integrated) combines the digital DVI signals and the analog VGA signals. For
the DVI-A and DVI-I, there are passive adapters available for the D-SUB VGA connector. There is
only one DDC channel available on the DVI-I interface. Therefore, the connector is not designed to
use both links (DVI and VGA) contemporaneously. Nevertheless, there are Y-cables available that
provide a DVI and VGA output contemporaneously. Such cables are not standardized and usually
provide the DDC only on the DVI or VGA output. Please be aware of the DDC when using such a
Y-cable.
The following schematic example shows a DVI-I implementation. It can also be used as an example
for a DVI-D design. Just remove the analog VGA signals. The sync signals for the VGA signals need
to be level shifted from 3.3V to 5V. The same is necessary for the DDC signals. The TDMS signals
need to be ESD protected by using diodes. The schematic example shows a discrete solution for the
level shifting and protection. There are also integrated solutions available.
To Next Page
Loading...