| 摘要 |
Circuitry is disclosed that comprises: a high voltage rail for providing a high voltage level corresponding to a first higher voltage domain; an intermediate voltage source, a low voltage rail; and a plurality of devices configured to operate in a second lower voltage domain; said circuitry being configured such that a first set of said plurality of devices are arranged in an upper voltage region where they are powered between said high voltage rail and an intermediate voltage rail powered by said intermediate voltage source and a second set of said plurality of devices are arranged in a lower voltage region where they are powered between said intermediate voltage rail and said low voltage rail, said circuitry being configured such that on power up said intermediate voltage source is powered before said high voltage rail, said circuitry further comprising: an isolating circuit arranged in said upper voltage region, said isolating circuit comprising at least one switching device for connecting said intermediate voltage source to at least one node in said circuitry in response to said high voltage rail being powered, and for isolating said at least one node from said intermediate voltage source and for connecting said at least one node to said high voltage rail in response to said intermediate voltage source being powered and said high voltage rail not being powered in order to impede current flow from said intermediate voltage source to said high voltage rail via said node when said high voltage rail is not powered. |
