Abstract: A data processing system and method for regulating a voltage supply to functional circuitry configured to operate from a variable voltage supply, the functional circuitry having at least one error correction circuit configured to detect and repair errors in operation of the functional circuitry. Voltage regulator circuitry provides the voltage supply to the functional circuitry, and modifies the voltage level of the voltage supply based on a feedback control signal. Error rate history circuitry receives error indications from the error correction circuit during operation of the functional circuitry and generates error rate history information therefrom. An adaptive controller then generates the feedback control signal in dependence on the error rate history information such that the adaptive controller adjusts the feedback control signal over time having regard to the error rate history information in order to obtain a predetermined target non-zero error rate within the functional circuitry.

Abstract: A latching device includes input and output latching elements to receive and output data values wherein the input and output elements are configured to receive a first and second clocks, respectively. The clocks have the same frequency but are inverted. The elements are transparent and transmit data between an input and an output in response to the first value of a received clock and are opaque and hold the data value in response to a second value of the received clock, such that in response to the first and second clocks the input data value is clocked through the input and output elements to the output. The device includes a device for selecting an operational data value or a diagnostic data value for input to the input element in response to a value of a diagnostic enable signal indicating a functional mode or a diagnostic mode.

Abstract: An integrated circuit is provided with operational mode header transistors which connect a virtual power rail to a VDD power supply. A controller circuit, responsive to a sensed voltage signal from a voltage sensor which reads the virtual rail voltage VVDD, generates a control signal which controls the operational mode transistors. The control signal is derived from an interface voltage power supply that provides higher voltage VDD IO than the VDD power supply and thus able to overdrive the operational mode transistors via either a gate bias voltage or a bulk bias voltage. The amount of leakage through the operational mode transistors is controlled in a closed loop feedback arrangement so as to maintain a predetermined target value or range for the virtual rail voltage. The operational mode transistor may also be controlled to support dynamic voltage and frequency scaling.

Abstract: A semiconductor memory storage device with a plurality of storage cells, each cell includes two access control devices, each providing the cell with access to or isolation from a respective one of two data lines in response to an access control signal provided by access control circuitry. The control devices are controlled to provide the storage cell with access to or isolation from either of the first and second of the two data lines. The access control circuitry is responsive to a data access request, the data access request being a write request, to apply a data value to be written to both of the first and second data lines and to apply the access control signal to both of the first and second access control lines.

Abstract: An apparatus and method are provided for detecting an approaching error condition within a data processing apparatus and includes a sequential storage structure arranged to latch an output signal generated by combinatorial circuitry dependent on a second clock signal. The sequential storage structure has a main storage element to latch a value of the output signal for provision to subsequent combinatorial circuitry. The sequential storage structure can be operated in either first or second modes of operation where, in the first mode, the predetermined timing window is ahead of a time at which the main storage element latches said value of the output signal enabling an approaching setup timing error to be detected. In the second mode, the predetermined timing window is after the time at which the main storage element latches said value of the output signal where an approaching hold timing error is detected.

Abstract: A voltage regulator for regulating a voltage level of a virtual power rail supplying power to logic circuitry in a low power data retention mode is disclosed. The voltage regulator comprises: switching circuitry having a transistor for coupling said virtual power rail to a power supply having a supply voltage level; control circuitry responsive to a signal indicating the logic circuitry is to enter the low data power retention mode to control the switching circuitry to switch to a conductive state in which the transistor is operating in a saturation region of operation and supplying a saturation current from the power supply via the virtual power rail to the logic circuitry; and a leakage power controller for adjusting a voltage level of the virtual power rail to control leakage power. The leakage power controller is configured to supply a bias voltage to the well in which the switching circuitry is formed, the saturation current of the switching circuitry being dependent on a value of the well bias voltage.

Abstract: An apparatus comprises a dynamic random-access memory (DRAM) for storing data. Refresh control circuitry is provided to control the DRAM to periodically perform a refresh cycle for refreshing the data stored in each memory location of the DRAM. A refresh address sequence generator generates a refresh address sequence of addresses identifying the order in which memory locations of the DRAM are refreshed during the refresh cycle. To deter differential power analysis attacks on secure data stored in the DRAM, the refresh address sequence is generated with the addresses of at least a portion of the memory locations in a random order which varies from refresh cycle to refresh cycle.

Abstract: A voltage regulator for regulating a voltage level of a virtual power rail supplying power to logic circuitry in a low power data retention mode is disclosed. The voltage regulator comprises: switching circuitry having a transistor for coupling said virtual power rail to a power supply having a supply voltage level; control circuitry responsive to a signal indicating the logic circuitry is to enter the low data power retention mode to control the switching circuitry to switch to a conductive state in which the transistor is operating in a saturation region of operation and supplying a saturation current from the power supply via the virtual power rail to the logic circuitry; and a leakage power controller for adjusting a voltage level of the virtual power rail to control leakage power. The leakage power controller is configured to supply a bias voltage to the well in which the switching circuitry is formed, the saturation current of the switching circuitry being dependent on a value of the well bias voltage.

Abstract: A semiconductor memory storage device is disclosed.

Abstract: A semiconductor memory storage device is disclosed, the memory having a plurality of storage cells.

Abstract: A monitoring circuit 14, 16, 18, 20, 22 for monitoring an operating parameter of an integrated circuit 2 comprises a ring oscillator circuit 80 comprising a plurality of serially connected inverting stages 82-1, 82-2, 82-3. At least one of the inverting stages 82-1, 82-2 comprises at least one leakage transistor 64-1, 64-2 which is configured to operate in a leakage mode in which substantially all current through the at least one leakage transistor is a leakage current, and a capacitive element 70-1 arranged to be charged or discharged in dependence on the leakage current. The ring oscillator circuit 80 thus generates an oscillating signal with an oscillation period dependent on a rate at which the capacitive element 70-1 is charged or discharged. The operating parameter controls a magnitude of the leakage current so that the oscillation period indicates the operating parameter.

Abstract: A data processing apparatus is provided comprising data processing circuitry configured to perform data processing operations. A plurality of state retention circuits forms part of the data processing circuitry and these circuits are configured to hold respective state values at respective nodes of the data processing circuitry it enters a low power mode. One or more scan paths connect the plurality of state retention circuits together in series, such that the state values may be scanned into and out of the respective nodes. A plurality of parity information generation elements are coupled to the scan path(s) and configured to generate parity information indicative of the respective state values held at those respective nodes by the state retention circuits.

Abstract: A data processing apparatus is provided which comprises a processor unit configured to perform data processing operations in response to a sequence of instructions and a storage unit configured to store data values for access by the processor unit when performing its data processing operations. Redundant error control data is stored in association with the data values, the redundant error control data enabling identification of an error in the data values. The data processing apparatus also comprises a data scrubbing unit configured to perform a data scrubbing process on at least a subset of the data values, the data scrubbing process comprising determining with reference to the redundant error control data if an error is present in that subset of data values and, where possible, correcting that error with reference to the redundant error control data.

Abstract: A semiconductor memory storage device is disclosed. The memory comprises a plurality of storage cells for storing data each storage cell comprising an access control device for providing the storage cell with access to or isolation from a data access port in response to an access control signal, access control circuitry for transmitting the access control signal along an access control line to control a plurality of the access control devices connected to the access control line.

Abstract: Sequential storage circuitry for a integrated circuit is provided, comprising a first storage element, a second storage element and an additional storage element. The first storage element stores, during a first phase of a clock signal, a first indication of an input data value received by the sequential storage circuitry. The second storage element is coupled to an output of the first storage element, and stores a second indication of the input data value during a second phase of the clock signal. The additional storage element is driven by a pulse signal derived from the clock signal, and is arranged on occurrence of that pulse signal to store a third indication of the input data value. Error detection circuitry is then provided for detecting a single event upset error in either the first storage element or the second storage element.

Abstract: A data processing system and method for regulating a voltage supply to functional circuitry of the data processing system is provided. The functional circuitry is configured to operate from a voltage supply whose voltage level is variable, the functional circuitry having at least one error correction circuit configured to detect errors in operation of the functional circuitry and to repair those errors in operation. Voltage regulator circuitry provides the voltage supply to the functional circuitry, and modifies the voltage level of the voltage supply based on a feedback control signal. Error rate history circuitry receives error indications from the error correction circuit during operation of the functional circuitry and generates error rate history information therefrom.

Abstract: A technique for characterising variation in a performance parameter(s) of circuit cells within a circuit cell library with perturbations in manufacturing process parameters uses a statistical approach whereby the statistical distribution of performance parameter(s) resulting from a joint distribution across manufacturing process parameter space is determined. The perturbation in manufacturing process parameter which results in a characteristic amount of variation is then identified and common sets of such perturbations used to group families of circuit cells together. Families of circuit cells have a correlation in their response to manufacturing process parameter perturbation and this is represented by a correlation matrix. Variation characterising data generated in accordance with the above technique is used to drive electronic design automation tools in integrated circuit design and manufacture.

Abstract: An apparatus and method are provided for detecting an approaching error condition within a data processing apparatus. The data processing apparatus includes a second sequential storage structure which is arranged to latch the output signal generated by combinatorial circuitry dependent on a second clock signal. The second sequential storage structure has a main storage element to latch a value of the output signal for provision to subsequent combinatorial circuitry, and transition detection circuitry for detecting a change of the value of the output signal latched by the main storage element during a predetermined timing window, said change indicating an approaching error condition whilst the value stored in the main storage element is still correct. The second sequential storage structure can be operated in either a first mode of operation or a second mode of operation.

Abstract: Power control circuitry for controlling connection of a voltage source to a switched power rail powering an associated circuit is provided. A plurality of switch blocks are connected in parallel between the switched power rail and the voltage source, each switch block being controlled by an enable signal provided by a switch controller. The switch controller performs a turn-on sequence providing a series of enable signal patterns to the switch blocks. The switch controller applies a time varying generation operation to at least one sequence stage of a predetermined turn-on sequence to produce a corresponding enable signal pattern for that sequence stage. When the turn-on sequence is later repeated, the enable signal pattern produced for at least one of the sequence stages differs from the enable signal pattern previously produced for that sequence stage.

Abstract: A semiconductor memory storage device is disclosed.