Apple Inc.
Supply tracking delay element in multiple power domain designs

Abstract:

An apparatus for delaying a signal transition is disclosed. The apparatus includes a first circuit coupled to a first power supply signal and a second, different power supply signal. The first circuit may be configured to, based on a voltage level of a logic signal, sink a current from an intermediate circuit node. A value of the current may be based upon a voltage level of the second different power supply signal. The apparatus also includes a second circuit coupled to the first power supply signal. The second circuit may be configured to generate an output signal based upon a voltage level of the intermediate circuit node. An amount of time between a transition of the logic signal and a corresponding transition of the output signal may be based on an amount of the current.