Power control circuit

Apparatus for controlling an integrated circuit, the integrated circuit comprising digital control circuitry, and the digital control circuitry comprising a serial interface, the apparatus comprising a power control device, the power control device being connected to a first input, for receiving a power-down signal, and a second input, for receiving a power-up signal, the power control device being adapted to power-down the digital control circuitry in response to the power-down signal and to power-up the digital control circuitry in response to the power-up signal, wherein the apparatus is arranged so that the power-down signal is sent to the first input via the serial interface and the power-up signal is sent to the second input via an external control line separate from the serial interface.

Apparatus for controlling an integrated circuit, comprising a power source for powering at least analogue circuitry included in the integrated circuit, a power-down circuit for powering down the analogue circuitry, and digital control circuitry adapted to control the powering down of the analogue circuitry by sending a control signal to the power-down circuit, the digital control circuitry also being adapted to power-down, wherein the apparatus further comprises switching means arranged so as to be closed when the digital control circuitry is powered down and when closed to connect the power source to the power down circuit so as to ensure that the analogue circuitry remains in a powered-down state.

(canceled)

A method of controlling an integrated circuit, comprising providing a power control device for controlling the power to at least part of the integrated circuit, receiving a power-up signal at the power control device via an input and powering-up the at least part of the integrated circuit if the at least part of the integrated circuit is in a powered-down state, and maintaining the at least part of the integrated circuit in the powered-up state regardless of any signal received via the input when the at least part of the integrated circuit is in a powered-up state, the method further comprising sending a signal to a component of the integrated circuit via the input when the at least part of the integrated circuit is in the powered-up state.

A method of controlling an integrated circuit, the integrated circuit comprising digital control circuitry, and the digital control circuitry comprising a serial interface, the method comprising powering-down the digital control circuitry in response to a power-down signal and powering-up the digital control circuitry in response to a power-up signal, the method further comprising sending the power-down signal via the serial interface and sending the power-up signal via an external control line separate from the serial interface.

A method of controlling an integrated circuit, the integrated circuit comprising analogue circuitry, a power-down circuit for powering down the analogue circuitry, and digital control circuitry adapted to control the powering down of the analogue circuitry, the method comprising sending a control signal to the power-down circuit via the digital control circuitry to power down the analogue circuitry, powering down the digital control circuitry, and connecting a power source to the power-down circuitry so as to maintain the analogue circuitry in a powered-down state when the digital control circuitry is powered down.

(canceled)

(canceled)