Patent ID: 7952417

Claim:
A mixed signal chip comprising a serial interface and a power control device for controlling the power to at least part of an integrated circuit on the chip, wherein said power control device is connected to said serial interface for receiving a power-down signal, and to an external control line separate from the serial interface for receiving a power-up signal, the power control device being adapted to power-up the at least part of the integrated circuit if a power-up signal is received at the external control line when the at least part of the integrated circuit is in a powered-down state, and the power control device being further adapted to maintain the at least part of the integrated circuit in the powered-up state regardless of any signal received at the external control line when the at least part of the integrated circuit is in a powered-up state, the mixed signal chip being arranged so that the external control line is also connected to a component of the integrated circuit with that component being configured to receive data via the external control line when the at least part of the integrated circuit is in the powered-up state.