Patent ID: 7469199

Claim:
In association with an electronic chip having a plurality of voltage domains, apparatus for monitoring levels of voltages of respective voltage domains, said apparatus comprising: a single conductive link coupled to said chip; a domain voltage selection network having a single output and a plurality of switchable inputs, said output being connected to said single conductive link, and two of said inputs being connected to monitor respective voltage levels of two of said plurality of voltage domains, wherein said single conductive link comprises only one pair of conductive c4 pins and wherein said single conductive link extends out from said chip to monitor a voltage level of each voltage domain from said plurality of voltage domains; a control mechanism disposed to operate said network to selectively connect one of said inputs to said single conductive link, wherein the control mechanism is adapted to operate voltage and ground multiplexers in said network to simultaneously couple said voltage level and a ground connection of the same domain to said single conductive link and said control signals are applied to said multiplexers in a pre-specified sequence; and a sensor device external to said electronic chip connected to measure said monitored respective voltage levels of two of said plurality of voltage domains using said single conductive link, wherein a voltage applied to said single conductive link is routed through a differential transmission line configured to suppress voltage noise, before the voltage is measured.