Patent ID: 8193789

Claim:
An intrinsically safe energy limited circuit, comprising: a source terminal for connecting to a voltage source; a return terminal for connecting to the voltage source; a parallel combination of a plurality of branch circuits, each branch circuit coupled at a first end thereof to the source terminal and each branch circuit coupled at a second end thereof to the return terminal, wherein each branch circuit includes a protected circuit component, a first resistor (R), and a first fuse in series; at least one drive circuit coupled between the second end of one or more branch circuits of the parallel combination and the return terminal, wherein the drive circuit further comprises at least one three-terminal semiconductor device having an output circuit and an input terminal coupled to and responsive to an output of a programmable control circuit; wherein substantially all of the dissipation of power in the at least one branch circuit caused by a short-circuited protected circuit component therein is shared between the fuse and the resistor in the at least one branch circuit.