Image generating device and communication circuit thereof

An image generating device, comprising:

• a high definition multimedia interface, a processor, a signal receiver, and a communication circuit;
• wherein
• the high definition multimedia interface has a pin;
• the signal receiver has a port;
• the communication circuit is coupled to the pin, comprising:
• a first pull-up resistor, an unidirectional current component, a signal isolation component and a signal switch;
• wherein,
• the first pull-up resistor receives a standby voltage;
• the unidirectional current component is coupled between the first pull-up resistor and the pin;
• the signal isolation component is coupled on a path between the pin and the signal switch, the signal isolation component has a first end and a second end, wherein the first end is coupled to the pin, and the signal isolation component is controlled by the standby voltage;
• and
• the signal switch is coupled to the second end of the signal isolation component, and the signal switch couples the second end of the signal isolation component to a second pull-up resistor of the processor or the signal switch couples the second end of the signal isolation component to a third pull-up resistor of the port according to a system voltage.