Patent attributes
A solid-state disconnect device capable of isolating and protecting circuits and equipment from overloads and undesired transients is presented. The protection device includes at least one depletion mode circuit block having three terminals (drain, gate, and source), which in its simplest form is implemented by a single n-channel depletion mode field-effect transistor, and two enhancement mode circuit blocks each having three terminals (drain, gate and source), each implemented in simplest form by a single n-channel enhancement mode field-effect transistor. The current conducting path of the first enhancement mode circuit block is connected in series with the current conducting path of the depletion mode circuit block. The drain terminal of the second enhancement mode circuit block is connected through a current limiting load to both the gate terminal of the second enhancement mode circuit block and the drain terminal of the first enhancement mode circuit block. The gate terminal of the first enhancement mode circuit block is connected to the drain terminal of the second enhancement mode circuit block. The source terminals of the two enhancement circuit blocks are both connected to the gate terminal of the depletion mode circuit block. Unidirectional and bidirectional embodiments are disclosed.
