Patent ID: 8514530

Claim:
A load control and protection system having a DC terminal (DCT) adapted to be coupled to a DC bus (DCB), a load terminal (LT) adapted to be coupled to a LOAD, a ground terminal (GT) adapted to be coupled to an external ground bus (EGB), wherein the GT is also adapted to be coupled to a peripheral circuit, and comprising: a ground fault detection circuit (GFDC) coupled to the GT and the DCT; an open ground switch circuit (OGSC) coupled to the LT; an internal ground bus (IGB) coupled between the GFDC and the OGSC; an open ground (OG) signal lead coupled between at least the GFDC and the OGSC; and a current limiting connection (CLC) coupled between the OGSC and the GFDC; wherein the GFDC is adapted to place an open ground signal on the OG signal lead when a connection between the GT and the EGB is not present; wherein the OGSC is adapted when in receipt of the open ground signal on the OG signal lead to couple the IGB to the LT, sense a current flowing from the GT to the LT via the IGB and energize the CLC between the GFDC and the LT to limit the current flowing from the GT through the control and protection system to the LT; and wherein the GFDC comprises a first transistor (M 1 ) having a first principal terminal coupled to the GT, and a second principal terminal coupled to the IGB, and a control terminal coupled to the CLC, and wherein the current from the GT flows through the first transistor (M 1 ) to the IGB.