Power control of powered devices in a system with power over the ethernet

A powered device in a system employing power over ethernet, the powered device comprising:

• a powered device interface including
• a supply sensing circuit configured to sense an amount of power allowed by the power source equipment for the powered device from at least one power source equipment over an ethernet cable,
• a demand sensing circuit configured to sense a power demand requested by the powered device, and
• a control circuit coupled with the supply sensing circuit and the demand sensing circuit, the control circuit configured to cause the power demand requested by the powered device to be reduced when the power demand requested by the powered device exceeds the amount of power allowed by the power source equipment for the powered device via reduction of at least one of the functionality of the powered device or the functionality of a system in which the powered device is operating;
• and
• an ALERT circuit configured to assert a warning signal to the system to reduce a power consumption of the system:
• and a voltage converter coupled with the powered device interface at a front end of the voltage converter, the voltage converter configured to receive an output from the control circuit to reduce the power demand requested by the powered device when the power demand requested by the powered device exceeds the amount of power allowed by the power source equipment for the powered device.

A method for limiting power requested by a powered device in a system employing power over ethernet, the method comprising:

• sensing, via a supply sensing circuit, an amount of power allowed by the power source equipment for the powered device from at least one power source equipment over an ethernet cable;
• sensing, via a demand sensing circuit, a power demand requested by the powered device;
• and
• reducing the power demand requested by the powered device, via a control circuit coupled with the supply sensing circuit and the demand sensing circuit configured to reduce of at least one of the functionality of the powered device or the functionality of a system in which the powered device is operating, when the power demand requested by the powered device exceeds the amount of power allowed by the power source equipment for the powered device by transmitting an output from the control circuit to a front end of a voltage converter to reduce the power demand requested by the powered device when the power demand requested by the powered device exceeds the amount of power allowed by the power source equipment for the powered device.