Patent ID: 7605644
Filing Date: 2009-10-20
Classification: H03K

Abstract:
1. An integrated circuit comprising: power switching circuitry coupled to a power source having a source voltage level and to a virtual power rail; logic circuitry coupled to said virtual power rail to draw power therefrom; and a power-on controller coupled to said power switching circuitry to control said power switching circuitry to operate in a plurality of modes include a pre-charge mode in which said virtual power rail is connected to said power source via a weak path during pre-charging of said virtual power rail and an active mode in which said virtual power rail is connected to said power source via a strong path during active operation of said logic circuitry; wherein said power-on controller comprises: a comparator responsive to a voltage on said virtual power rail passing a reference voltage, while being driven toward said source voltage by conduction through said power switching circuitry during said pre-charge mode, to output a sense signal; and a latch responsive to said sense signal to latch a trigger signal coupled to said power switching circuitry to switch said power switching circuitry to said active mode.