Method apparatus comprising integrated circuit and method of powering down such circuit
View Patent ↗The present invention relates to a mobile apparatus comprising an integrated circuit to operate predefined functions, which integrated circuit is susceptible to be set in a standby operating mode wherein which said circuit can resume operation within a predefined delay. The circuit comprises configuration sequential logic having defined states that need to be stored before the circuit enters in standby mode. The mobile apparatus further comprises a power down unit for storing the states of the configuration sequential logic into a low leakage storage area during standby mode that reduces standby current considerably.
1. A mobile apparatus comprising:
an integrated circuit block configured to perform predefined functions, the circuit block being susceptible to be set in a standby operating mode wherein which said circuit block can resume operation within a predefined period of time, said circuit block comprising configuration sequential logic and functional sequential logic having defined states; and
a power down unit configured to respond to a request to switch from an active operating mode to the standby operating mode by:
determining whether there is an active Input/Output transfer;
when there is an active Input/Output transfer, terminating the Input/Output transfer, and subsequently storing states of the configuration sequential logic into a state recovery storage area and powering down the circuit block except for the state recovery storage area; and
when there is not an active Input/Output transfer, storing states of the configuration sequential logic into state recovery storage area and powering down the circuit block except for the state recovery storage area.
2. The mobile apparatus as claimed in claim 1 , wherein the circuit block comprises different logic blocks to distinguish between the configuration sequential logic and the functional sequential logic, so that only the states of the configuration sequential logic are relevant to be stored into said state recovery storage area.
3. The mobile apparatus as claimed in claim 1 wherein said power down unit comprises a power down control unit configured to control activity levels of the circuit block.
4. The mobile apparatus as claimed in claim 1 , further comprising a plurality of wake-up request detectors configured to detect wake-up requests for the circuit block to be powered up again from the standby operating mode into the active operating mode.
5. The mobile apparatus as claimed in claim 1 wherein the states of the configuration sequential logic consist of information data, said data being shifted serially from the configuration sequential logic into the state recovery storage area before the circuit block is powered down in standby mode.
6. The mobile apparatus as claimed in claim 1 wherein the states of the configuration sequential logic consist of information data, the circuit block being arranged so that said data are loaded in parallel from the configuration sequential logic into the state recovery storage area, using storage cell lines to store and reload the data.
7. The mobile apparatus as claimed in claim 5 wherein the circuit comprises dedicated flip-flops configured to perform multiplexing/demultiplexing of store and reload lines.
8. The mobile apparatus as claimed in claim 1 wherein said circuit block is an Input/Output peripheral block configured to enable said mobile apparatus to communicate with peripheral devices.
9. The mobile apparatus of claim 1 wherein the apparatus is configured to respond to a request to switch from the stand-by operating mode to the active operating mode by:
powering up the circuit block;
reloading states stored in the state recovery storage area into the configuration sequential logic; and
resuming the active operating mode of the circuit block.
10. The mobile apparatus of claim 9 wherein the apparatus is configured to respond to the request to switch from the stand-by operating mode to the active operating mode by loading default states of the functional sequential logic before resuming the active operating mode of the circuit block.
11. A method, performed by a mobile device, comprising:
receiving a request to switch a circuit of the mobile device from an active mode to a standby mode, mode of operation: and
under control of a power-down unit of the mobile device,
determining whether any Input/Output transfers are active;
when it is determined that Input/Output transfers are active, terminating the Input/Output transfers and subsequently storing states of configuration sequential logic of the circuit into state recovery storage area and powering down the circuit except the state recovery storage area; and
when it is determined that Input/Output transfers are not active, storing states of configuration sequential logic of the circuit into state recovery storage area and powering down the circuit except the state recovery storage area.
12. The method as claimed in claim 11 wherein the circuit comprises functional sequential logic and the storing is limited to storing states of the configuration sequential logic in the state recovery storage area.
13. The method as claimed in claim 11 wherein the step of storing the states of the configuration sequential logic into the state recovery storage area is performed serially.
14. The method as claimed in claim 11 wherein the step of storing the states of the configuration sequential logic into the state recovery storage area is performed in parallel.
15. The method of claim 11 , further comprising:
responding to a wake-up request by:
powering up the circuit;
reloading states stored in the state recovery storage area into the configuration sequential logic; and
resuming the active operational mode of the circuit.
16. The method of claim 15 wherein the resuming the active operational mode of the circuit comprises resuming operation of functional sequential logic of the circuit in a default state of the functional sequential logic.