Patent ID: 8625029

Claim:
A circuit for detection of an HDMI source device to an HDMI sink device through an HDMI sink connector without regard for the activity state of the HDMI source device, comprising in combination: a pull-up resistor having first and second terminals with the first terminal coupled to a DC power source; a switching device coupled between the pull-up resistor's second terminal and ground at a circuit node; the switching device being switched on to couple the circuit node to ground when power is applied to a control terminal thereof from the HDMI sink connector power pin, and being switched off otherwise; the circuit node being further coupled to a DDC and a CEC ground connection of the HDMI sink connector; and the circuit node being readable as a binary signal to indicate the presence of a source device to the HDMI sink connector, wherein the node exhibits a logic low signal when either the node is grounded by the DDC and CEC ground connection to a source device or when the switching device is switched on.