| 摘要 |
A power input protection circuit for an electrical device including a pass device having a full-conduction state, an off state, and a current regulation state, a control device coupled to the pass device for signaling the pass device to operate in one of the full-conduction, off or current regulation states, a high-voltage sensing circuit coupled to the control device for signaling the presence of an over-voltage condition to the control device, a high-current sensing circuit coupled to the control device for signaling the presence of an over-current condition to the control device, and an energy storage circuit coupled to the regulator and for supplying energy to the regulator when the pass device is in the off state is disclosed. In one embodiment the high-current sensing circuit comprises an input current sensor having a first input and a second input, a second voltage reference coupled to the first input, and a current measuring circuit coupled to the second input and the high-voltage sensing circuit comprises an input voltage sensor having a first input and a second input, a first voltage reference coupled to the first input, and an input voltage measuring circuit coupled to the second input. The pass device blocks the flow of current through the voltage regulator when the pass device is in the off state and limits the flow of current through the voltage regulator when the pass device is in the current regulation state.
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