Abstract: A voltage regulation scheme for an on-chip voltage generator includes a voltage sensing circuit (VSC) and a configurable buffer circuit (CBC) to regulate the on-chip voltage generator. The CBC generates an output signal that is received by the on-chip voltage generator to activate and de-activate the voltage generator. The VSC generates a voltage level detection (VLD) signal having a voltage level that is a function of the level of the on-chip generated voltage. The CBC receives a control signal that is used to dynamically configure the chip into an operational mode, as well as the VLD signal. In response to the control signal, the switch threshold of the CBC is configured to a predetermined level corresponding to the selected operational mode. The predetermined trip point causes the CBC to appropriately activate and de-activate the on-chip voltage generator to regulate the on-chip generated voltage at the level required by the configured operational mode.

Abstract: True and complement data signals are provided to a multiplexer, which selects one of them based on a selection signal for capture by a single scannable latch in response to a clock signal. The scannable latch then provides the captured signal for testing by testing logic.

Abstract: A local bit switch selecting circuit and method for systems having a first number of banks of sense amplifiers with a second number of sense amplifiers in each sense amplifier bank. The bit switch selecting circuit and method use a single N channel field effect transistor in each sense amplifier bank. This provides bit switch selecting capability while significantly reducing the number of devices and chip area required.

Abstract: A circuit for a DRAM is described which, when in test mode, notifies a tester when the self-refresh operation of a dynamic random access memory (DRAM) reaches various stages of completion. By signaling the tester when, i.e., ⅛, ¼, ½, etc. of the self-refresh cycle is reached, the amount of time needed for verification of the self-refresh oscillator frequency is reduced correspondingly by a factor of 8, 4, 2 etc. The signaling of a partial test time is achieved by adding self-refresh status logic circuits which decode the high order most significant bits of the refresh address counter. The activation of the third most significant bit signals completion of ⅛th of the self-refresh cycle, the activation of the second most significant bit signals completion of ¼th of the self-refresh cycle, the activation of the most significant bit signals completion of ½ of the self-refresh cycle, and deactivation of the most significant bit signals completion of the self-refresh cycle.

Abstract: A charge pump limits the voltages at nodes internal to the charge pump to reduce the risk of junction breakdown in the charge pump. The charge pump includes a first pump circuit, a second pump circuit, a first clamp and a second clamp. The first clamp limits the voltage level of a well by providing a current path from the well to the output lead when the voltage level of the well reaches a first predetermined limit. The voltage level at a node from which charge is redistributed to the well is limited by the second clamp, which is configured to provide a conductive path from the node to the output lead when the voltage level of the node reaches a second predetermined limit. The pump circuits can each include a logic circuit that is configured, depending on the level of an external supply voltage, to reduce the rate at which the capacitor node is boosted when the external supply voltage is relatively high.

Abstract: A crow-bar current reduction circuit for use with a NMOS output circuit a gate voltage control circuit (GVC). The GVC receives a data signal and an output enable signal and generates control signals to drive the gates of the output transistors of the output circuit. When enabled, the GVC delays the rising edges of the gate control signals so as to help ensure that during a transition of the output signal generated by the output circuit, the NFET that was conductive before the transition is "turned off" to become non-conductive before the NFET that was non-conductive before the transition is "turned on" to become conductive. When adapted for a CMOS output circuit, the GVC delays the rising edge of the gate control signal provided to the NMOS pull-down transistor and delays the falling edge of gate control signal provided to the PMOS pull-up transistor.

Abstract: A timing circuit can be selectively configured to generate output pulses in response to either the falling edges or the rising edges of an input signal. The timing circuit includes a multiplexer, an output pulse width controller (OPWC), a gating circuit (GC) and a latch circuit. The OPWC includes a delay circuit that can be configured to provide a predetermined delay .delta. that can be larger than the pulse width of the input signal pulses. The multiplexer is connected to receive a first input signal and an inverted version of a second input signal. The first input signal is used in a rising edge triggered mode, whereas the second input signal is used in a falling edge triggered mode. The multiplexer receives a mode signal to selectively output one of the input signals to the GC. The GC is also connected to receive the output signal from the OPWC.

Abstract: A regulator system for an on-chip-generated supply voltage includes a voltage detection circuit, a power-up mode detection circuit, a normal mode detection path, and a power-up detection path. The voltage detection circuit monitors the on-chip-generated supply voltage and generates a signal that indicates the level of this supply voltage. The power-up mode detection circuit detects when the chip is in the power-up mode and generates a path select signal. The path select signal causes the regulator system to select the power-up detection path during the power-up mode and to select the normal detection path when not in the power-up mode. The power-up detection path includes voltage regulation circuitry that does not rely on a reference voltage. In one embodiment, the power-up detection path includes a logic gate coupled to receive the signal from the voltage detector. The logic gate is skewed to have a trip point that corresponds to voltage level slightly greater than that of the external supply voltage.

Abstract: A timing scheme for multiple data clock activation with programmable delay for use in accessing a multiple CAS latency memory device. A multi-stage data propagation path is used to propagate a bit being accessed from a memory array of the device to an output line. Timing signals are generated so that in a CAS latency three mode, the timing signal that activates the next to last stage of the propagation path is triggered by an output clock signal that activates the last stage of the propagation path so that pulse from the output clock signal does not overlap with pulses of the timing signal that activates the previous stage. This timing scheme ensures the data lines feeding the last stage are not being restored while the last stage is sensing these data lines. A programmable delay circuit is used to adjust the timing of the output clock signal.

Abstract: The present invention provides a method and apparatus that accomplishes a high performance, random read/write SDRAM design by synchronizing the read and write operations at the data line sense amplifier. This enables the design to perform random read and write operations without varying cycle time issues or unbalanced margin issues. The data lines are used as bi-directional lines to accomplish high performance reads and writes with minimal additional wiring overhead required. During a read operation, read data is transferred from the memory cells of the device across a series of consecutive pairs of data lines to an input/output port of the memory device. The first pair of data lines is coupled to a data line sense amplifier. The additional pairs of data lines are coupled to additional amplifiers. During a read operation, data is transferred across the consecutive pairs of data lines according to the timing cycles of the respective amplifiers.

Abstract: A regulator system includes first and second voltage sensing circuits coupled to a voltage generator control circuit. The first and second voltage sensing circuits are configured to monitor the voltage generated by the on-chip voltage generator (i.e., the on-chip supply voltage) and detect when the on-chip supply voltage reaches thresholds that are predetermined to define a desired range of the on-chip supply voltage. The voltage generator control circuit receives voltage sense signals from the voltage sense circuits and, in response, asserts or de-asserts a control signal received by the on-chip voltage generator so as to activate or de-activate the on-chip voltage generator to maintain the on-chip supply voltage within the desired range. The voltage generator control circuit introduces hysteresis in the generation of the control signal provided to the on-chip voltage generator.

Abstract: The present invention is a system and method of testing logic circuits in memory of an integrated circuit in a fraction of the time. The present invention discloses a system and method to allow testing imbedded array logic blocks in parallel, rather than sequentially. The present invention allows for the testing of multiple logic blocks associated with different memory or column locations at the same time. This technique allows for reduction in test time by a factor of X, where X is the number of rows or columns or memory cells feeding logic.

Abstract: A circuit for disabling a two-phase charge pump includes a pump select circuit and a disable control circuit. The pump select circuit is configured to select one control signal from a plurality of control signals in response to at least one select signal. The selected signal is in effect provided to the disable control circuit, which also receives a pump disable signal. A voltage sensing circuit asserts the pump disable signal when the pumped voltage reaches a predetermined maximum level. While the pump disable signal is de-asserted, the disable control circuit in effect provides the selected signal to the two-phase charge pump as a pump control signal. However, when the pump disable signal is asserted, the disable control signal latches the current logic level of the pump control signal so that the pump control signal does not transition while the pump disable signal is asserted.

Abstract: A method and apparatus for testing circuitry, such as a memory or a logic circuit, having a plurality of outputs, includes a built-in self-testing (BIST) test state machine for generating a plurality of address outputs, a plurality of multiplexers controlled by the address outputs of the test state machine, and a testing device for testing the plurality of outputs of the circuitry based on the address outputs of the test state machine. The plurality of outputs of the circuitry are input to the plurality of multiplexers and a number of outputs tested simultaneously is less than a total number of outputs of the circuitry.

Abstract: A semiconductor memory device with a pair of data lines for reading and writing data signals to and from a matrix of memory cells and an accelerator circuit for accelerating the generation of a data signal on at least one of the data lines is disclosed. Slow signal generation on the data lines is due to the characteristics of NFET pass gates passing high signals, or PFET pass gates passing low signals. In an implementation using NFET pass gates, the accelerator circuit includes a pair of cross-coupled PFET transistors, one of which is activated by the low signal on the opposing data line. The drains of the cross-coupled PFET transistors are coupled to the data lines, such that when the low signal on the opposing data line activates one of the PFETs, it supplies additional current to the data line receiving the high signal, so as to accelerate the generation of the high signal on the data line.

Abstract: A memory Array Built-In Self-Test (ABIST) circuit is disclosed that will test a multi-port memory array. A programmable pattern generator for the ABIST circuit allows for different R/W data operations to be performed at the same or adjacent address locations within a multi-port memory array. The programmable pattern generator comprises a data generator, a read/write controller, and an address counter, each having the same number of outputs as ports of the multi-port memory array. The programmable pattern generator also comprises a frequency controller. The data generator is programmed with the appropriate data patterns for the memory array, and the read/write controller is programmed with the appropriate read/write patterns for the memory array. The address counter is to provide the same or different addresses on each port of the multi-port array, and the frequency controller is programmed with the appropriate frequency information to determine the number of read/write operations per cell in the memory array.

Abstract: An ABIST circuit for testing a memory array has a blanket write subcycle (WC), an RC3 subcycle, and an RC4 subcycle. The ABIST circuit includes a programmable pattern generator that provides eight programmable data bits, eight programmable read/write bits, and two programmable address frequency bits to determine the specific test patterns applied to the memory array. The address frequency bits determine how many memory cycles will be performed on each cell of the memory array. In X1 mode, only one memory cycle is performed on each cell during any given subcycle. In X2 mode, two memory cycles are performed on each cell, allowing a cell to be written, then subsequently read in the same subcycle. In X4 mode, four memory cycles are performed on each cell, and in X8 mode, all eight bits of read/write and data are used on each cell, resulting in eight memory cycles for each cell within the memory array.

Abstract: The present invention provides a device for testing memory having write cycles and read cycles. A BIST state machine changes the data applied to the memory's DI port during read cycles to a value different from that of the data stored in the currently addressed memory location. The BIST-generated expect data also is at a different value from that of data at the memory's DI port and at the same value as the data stored at the current memory address location during read operations. With this arrangement, flush through defects can be detected which would not have been detectable by prior BIST machines.

Abstract: An ABIST circuit for testing a memory array has a blanket write subcycle (WC), an RC.sub.3 subcycle, and an RC.sub.4 subcycle. The ABIST circuit includes a programmable pattern generator that provides eight programmable data bits, eight programmable read/write bits, and two programmable address frequency bits to determine the specific test patterns applied to the memory array. The address frequency bits determine how many memory cycles will be performed on each cell of the memory array. In X1 mode, only one memory cycle is performed on each cell during any given subcycle. In X2 mode, two memory cycles are performed on each cell, allowing a cell to be written, then subsequently read in the same subcycle, In X4 mode, four memory cycles are performed on each cell, and in Xg mode, all eight bits of read/write and data are used on each cell, resulting in eight memory cycles for each cell within the memory array.

Abstract: A method and circuit are provided to detect if any bit stored in a given location in a memory is different from the data expected. The circuit includes logic to read each of the bits stored in the cells at given locations from memory and to generate a fail signal based on the data expected to be stored if the stored data is different from the expected data. The circuit also preferably includes logic to compare the True data and expect data read from each cell and generating the fail signal if they are the same. Additional logic circuitry is also preferably provided which determines if a node of the circuit remains in a precharged condition.