The HDMI Forum makes an addition to the new HDMI 2.1a specification, in the form of Cable Power. This function should make it easier to use longer active HDMI cables. Cables are supplied with power directly from the HDMI connection.
HDMI Forum introduces HDMI Power Cable an amendment to the HDMI 2.1a specification. With this feature, active HDMI cables can be powered directly from the HDMI connection, without having to connect a separate power cable. This should simplify the use of active HDMI cables, the HDMI Forum argues. The feature allows cables to draw up to 300mA at 5V from the HDMI connection.
To use the feature, you need both a cable and a ‘source device’ that supports HDMI Power Cable. HDMI Power Cable cables also receive a detachable power connector for use with devices that are not compatible with the feature. According to the HDMI Forum, those will be USB-C or USB-Micro-B connections.
Active HDMI cables are mainly used to enable longer cable lengths. With passive cables, stability problems can occur due to signal loss from certain lengths. HDMI Power Cable should make using active HDMI cables as easy as connecting passive cables.