Patent ID: 6944695
Filing Date: 2005-09-13
Classification: G06F

Abstract:
1. An apparatus for connecting at least one of a plurality of devices to a two-wire serial bus having a primary bus having a primary bus first bus line and a primary bus second bus line, comprising: an isolated bus having an isolated bus first bus line and an isolated bus second bus line; a first circuit for individually generating a control signal at one of the at least one of a plurality of devices coupled via the isolated bus to the two-wire serial bus; and a second circuit for disconnecting the isolated bus first bus line from the primary bus first bus line when a control signal is negated and the second circuit for connecting the isolated bus first bus line to the primary bus first bus line when the control signal is being asserted, the second circuit including: a first NAND gate having a first NAND gate first input, a first NAND gate second input coupled to the control signal, and a first NAND gate output; a second NAND gate having a second NAND gate first input, a second NAND gate second input, and a second NAND gate output, wherein: a third NAND gate having a third NAND gate first input coupled to the control signal, a third NAND gate second input coupled to the primary bus first bus line, and a third NAND gate output coupled to the second NAND gate second input; a first analog switch coupled between the primary bus first bus line and the isolated bus first bus line and controlled by the second NAND gate output; and a second analog switch coupled between the primary bus second bus line and the isolated bus second bus line and controlled by the second NAND gate output.