Patent ID: 7365450

Claim:
A current cutoff circuit for use in a load control circuit for controlling an electric circuit including a load, the load control circuit including a switching unit for switching an operation state of the load, the current cutoff circuit comprising: a switching device connected to the electric circuit; a first detection circuit, connected to the switching unit, for detecting current or voltage of the switching unit; a switch control circuit, connected to the switching unit, the switching device, and the first detection circuit, for sending a control signal to the switching unit, the switch control circuit determining that a fault has occurred in the switching unit when the detection of the first detection circuit indicates that the switching unit is in an activated state in spite of sending the control signal for inactivating the switching unit and opening the switching device to configure an open circuit with the electric circuit; and a second detection circuit, having a detector monitor potential with a current and voltage parameter, connected between the switch control circuit and the electric circuit, for detecting the current and voltage parameter based on the operation state of the electric circuit, wherein the switch control circuit sends an operation enablement signal to the switching device, determines whether there is a fault in the switching device based on the operation enablement signal sent to the switching device and the detection of the second detection circuit, and disables operation of the switching unit when there is a fault.