Patent ID: 6355936
Filing Date: 2002-03-12
Classification: H04B

Abstract:
An electrical insulation circuit of the type connected between a peripheral circuit that includes a supply terminal, a ground terminal, and first and second signal terminals, and a two-way bus that includes at least one supply wire, a ground wire, and first and second data wires, each of the data wires conveying differential data signals in both directions, said electrical insulation circuit comprising:first and second optocouplers for transmitting differential signals in the peripheral circuit-to-bus direction; and third and fourth optocouplers for transmitting differential signals in the bus-to-peripheral circuit direction, wherein the first and third optocouplers are associated with the first signal terminal on the peripheral circuit side and with the first data wire on the bus side, the second and fourth optocouplers are associated with the second signal terminal on the peripheral circuit side and with the second data wire on the bus side, and the first and third optocouplers and the second and fourth optocouplers are connected such that the first and second optocouplers are off during the transmission of differential signals in the bus-to-peripheral circuit direction and the third and fourth optocouplers are off during the transmission of differential signals in the peripheral circuit-to-bus direction.