Abstract: A functional circuit is coupled to a power supply conductor by at least one power gating transistor. A switching device applies a gate drive voltage to a gate terminal of the power gating transistor via a resistive element. The power gating transistor provides a Miller capacitance between its drain and gate terminals. The Miller capacitance, the resistance of the resistive element, and the drive strength of the switching device are configured such that, in response to the switching device switching the gate drive voltage to allow more current to pass through the power gating transistor, the Miller capacitance provides a feedback mechanism competing against the switching device to reduce the slew rate of the gate drive voltage such that the current passing between the power gate supply conductor and the functional circuit through the power gating transistor is less than the saturation current of the power gating transistor.

Abstract: Memory circuitry 2 includes a memory cell 12 coupled to a plurality of bit line pairs 18, 24 providing multiple access ports. Write boost circuitry 36 serves to increase a write voltage applied to write a data value into the memory cell during at least a boost period of a write access. Collision detection circuitry 10 detects when the write access at least partially overlaps in time with a read access. If a collision is detected, then write assist circuitry serves to drive the bit line pair of the detected read access with a write assist voltage difference having the same polarity as the write voltage and a magnitude less than the write voltage with the boost voltage applied. The write assist circuitry drives the bit line pair of the colliding read independently of the write boost circuitry applying the boost voltage such that the boost voltage is undiminished by the action of the write assist circuitry.

Abstract: A timing control circuit comprises at least three current control units coupled in parallel between a first circuit and a second circuit node. The current control units each have an active mode and an inactive mode. The current control units are responsive to a timing trigger event to pass current whose magnitude is dependent on how many of the current control units are in the active mode. The current control units comprise a plurality of groups. Current control units within a same group are responsive to a change in a bit of a control value corresponding to that group to switch together between the active and inactive modes, such that the magnitude of the current is dependent on which of the groups are in the active mode. The signal timing in the associated circuit is varied in dependence on the magnitude of the current.

Abstract: An integrated circuit and method are provided, the integrated circuit comprising retention voltage generation circuitry which receives a supply voltage from a supply voltage node and provides a retention voltage at a retention voltage node. Functional circuitry is connected between the retention voltage node and a reference voltage node, the functional circuitry being held in a data retention state when at least a minimum voltage is provided between the retention voltage node and the reference voltage node.

Abstract: A timing circuit and corresponding method are provided to generate an output timing signal in dependence on an input timing signal. The timing circuit comprises a plurality of circuit components, each circuit component configured to receive an input dependent on the input timing signal and to generate an output in dependence on that input. Each circuit component performs switching operations by switching its output level in response to a transition of its input level. Each circuit component exhibits a delay in switching its output level, the delay comprising a first delay associated with a first switching of its output level and a second delay associated with a second switching of its output level. The first switching is in an opposite direction to the second switching and the first delay and the second delay exhibit a change in magnitude as each circuit component repeatedly performs its switching operations.

Abstract: A timing circuit and corresponding method are provided to generate an output timing signal in dependence on an input timing signal. The timing circuit comprises a plurality of circuit components, each circuit component configured to receive an input dependent on the input timing signal and to generate an output in dependence on that input. Each circuit component performs switching operations by switching its output level in response to a transition of its input level. Each circuit component exhibits a delay in switching its output level, the delay comprising a first delay associated with a first switching of its output level and a second delay associated with a second switching of its output level. The first switching is in an opposite direction to the second switching and the first delay and the second delay exhibit a change in magnitude as each circuit component repeatedly performs its switching operations.

Abstract: A timing control circuit comprises at least three current control units coupled in parallel between a first circuit and a second circuit node. The current control units each have an active mode and an inactive mode. The current control units are responsive to a timing trigger event to pass current whose magnitude is dependent on how many of the current control units are in the active mode. The current control units comprise a plurality of groups. Current control units within a same group are responsive to a change in a bit of a control value corresponding to that group to switch together between the active and inactive modes, such that the magnitude of the current is dependent on which of the groups are in the active mode. The signal timing in the associated circuit is varied in dependence on the magnitude of the current.

Abstract: A memory device, and method of operation of such a device, are provided. The memory device comprises an array of memory cells arranged in a plurality of rows and a plurality of columns, at least one bit line being associated with each column. Column multiplexer circuitry is coupled to the plurality of columns, for inputting write data into a selected column during a write operation and for outputting an indication of read data sensed from a selected column during a read operation. The column multiplexer circuitry comprises a single pass gate transistor per bit line, and latch circuitry is then used to detect the read data from the indication of read data output by the column multiplexer circuitry during the read operation, and to store that detected read data. Such an approach provides a particularly area efficient construction for the column multiplexer circuitry whilst enabling correct evaluation of the read data held in the addressed memory cell.

Abstract: A memory device and method of operating such a device are provided. The memory device has a plurality of sub-arrays arranged to form at least one sub-array column having a first end and a second end, with each sub-array comprising a plurality of memory cells arranged in a plurality of memory cell rows and at least one memory cell column. Sub-array access circuitry is associated with each sub-array, for detecting read data from a selected memory cell column of the associated sub-array during a read operation, and global access circuitry then interfaces with the first end of the sub-array column.

Abstract: A read only memory cell for storing a multiple bit value is disclosed. The read only memory cell comprises: at least three output lines, each of the at least three output lines representing a different multiple bit value; a switching device connected between a single one of the three output lines and a voltage source. The switching device provides an electrical connection between the voltage source and the single one of the three output lines in response to a switching signal, a voltage of the connected output line switching value in response to connection to the predetermined voltage and the multiple bit value represented by the output line is thereby selected. There is also an output device provided for outputting the selected multiple bit value.

Abstract: A read only memory cell for storing a multiple bit value is disclosed. The read only memory cell comprises: at least three output lines, each of the at least three output lines representing a different multiple bit value; a switching device connected between a single one of the three output lines and a voltage source. The switching device provides an electrical connection between the voltage source and the single one of the three output lines in response to a switching signal, a voltage of the connected output line switching value in response to connection to the predetermined voltage and the multiple bit value represented by the output line is thereby selected. There is also an output device provided for outputting the selected multiple bit value.

Abstract: A data processor includes a memory device having an array of memory cells for storing data values. Test circuitry executes one or more test patterns to detect any memory cells which may malfunction. Each test pattern causes a sequence of access requests to be issued to the memory device where the timing of the sequence is controlled by a test mode clock signal. Dummy read control circuitry is responsive at least to each write access request to generate an internal clock signal which has an increased frequency with respect to the test mode clock signal. The dummy read control circuitry performs, using the internal clock signal, a write operation to at least one memory cell based on a memory address specified by the write access request, followed by a dummy read operation to the same memory cell, serving to stress the memory cell with respect to cell stability.

Abstract: A memory device and method of operating such a device are provided. The memory device has a plurality of sub-arrays arranged to form at least one sub-array column having a first end and a second end, with each sub-array comprising a plurality of memory cells arranged in a plurality of memory cell rows and at least one memory cell column. Sub-array access circuitry is associated with each sub-array, for detecting read data from a selected memory cell column of the associated sub-array during a read operation, and global access circuitry then interfaces with the first end of the sub-array column.

Abstract: A memory device, and method of operation of such a device, are provided. The memory device comprises an array of memory cells arranged in a plurality of rows and a plurality of columns, at least one bit line being associated with each column. Column multiplexer circuitry is coupled to the plurality of columns, for inputting write data into a selected column during a write operation and for outputting an indication of read data sensed from a selected column during a read operation. The column multiplexer circuitry comprises a single pass gate transistor per bit line, and latch circuitry is then used to detect the read data from the indication of read data output by the column multiplexer circuitry during the read operation, and to store that detected read data. Such an approach provides a particularly area efficient construction for the column multiplexer circuitry whilst enabling correct evaluation of the read data held in the addressed memory cell.

Abstract: A memory device and method of operation are provided. The memory device comprises a plurality of memory cells arranged in at least one column, during a write operation a data value being written to an addressed memory cell within a selected column from said at least one column. A supply voltage line is associated with each column, the supply voltage line being connectable to a first voltage source to provide a supply voltage at a first voltage level to the associated column. Threshold circuitry is connected to a second voltage source having a second voltage level, the threshold circuitry having a threshold voltage. Control circuitry is used during the write operation to disconnect the supply voltage line for the selected column from the first voltage source, and to connect the threshold circuitry to the supply voltage line for the selected column.

Abstract: A memory device and method of operation is provided, the memory device having a plurality of memory cells arranged in at least one column, with each column having at least one bit line and a supply voltage line associated therewith. A capacitance exists between the supply voltage line and associated at least one bit line for each column. Control circuitry is used to control, for each column, connection of a voltage source to the associated supply voltage line. For a predetermined period during a memory access operation, the control circuitry disconnects the supply voltage line for at least the selected column from the voltage source, such that a voltage level on that supply voltage line changes in response to any change in voltage on the associated at least one bit line. This basic mechanism can be used to provide a variety of assist mechanisms, such as a write assist mechanism, a bit flip assist mechanism and a read assist mechanism.

Abstract: A data processing apparatus and method are provided for testing stability of memory cells in a memory device. A data processing apparatus comprises a memory device having an array of memory cells for storing data values. Test circuitry is employed in a test mode of operation to execute one or more test patterns in order to detect any memory cells which may malfunction in a normal mode of operation due to cell instability following a write operation, as for example may be caused by body region history effect in embodiments where each memory cell comprises at least one transistor having a body region insulated from a substrate. Each test pattern causes a sequence of access requests to be issued to the memory device whose timing is controlled by a test mode clock signal. Dummy read control circuitry is employed in the test mode of operation, and is responsive at least to each write access request to generate an internal clock signal which has an increased frequency with respect to the test mode clock signal.

Abstract: A memory device and method of operation are provided. The memory device comprises a plurality of memory cells arranged in at least one column, during a write operation a data value being written to an addressed memory cell within a selected column from said at least one column. A supply voltage line is associated with each column, the supply voltage line being connectable to a first voltage source to provide a supply voltage at a first voltage level to the associated column. Threshold circuitry is connected to a second voltage source having a second voltage level, the threshold circuitry having a threshold voltage. Control circuitry is used during the write operation to disconnect the supply voltage line for the selected column from the first voltage source, and to connect the threshold circuitry to the supply voltage line for the selected column.

Abstract: A memory device and method of operation is provided, the memory device having a plurality of memory cells arranged in at least one column, with each column having at least one bit line and a supply voltage line associated therewith. A capacitance exists between the supply voltage line and associated at least one bit line for each column. Control circuitry is used to control, for each column, connection of a voltage source to the associated supply voltage line. For a predetermined period during a memory access operation, the control circuitry disconnects the supply voltage line for at least the selected column from the voltage source, such that a voltage level on that supply voltage line changes in response to any change in voltage on the associated at least one bit line. This basic mechanism can be used to provide a variety of assist mechanisms, such as a write assist mechanism, a bit flip assist mechanism and a read assist mechanism.