Patent application number | Description | Published |
20100277219 | Clock Gater with Test Features and Low Setup Time - A clock gater circuit comprises a plurality of transistors having source-drain connections forming a stack between a first node and a supply node. A given logical state on the first node causes a corresponding logical state on an output clock of the clock gater circuit. In one embodiment, a first transistor of the plurality of transistors has a gate coupled to receive an enable input signal. A second transistor is connected in parallel with the first transistor, and has a gate controlled responsive to a test input signal to ensure that the output clock is generated even if the enable input signal is not in an enabled state. In another embodiment, the plurality of transistors comprises a first transistor having a gate controlled responsive to a clock input of the clock gater circuit and a second transistor having a gate controlled responsive to an output of a delay circuit. The delay circuit comprises at least one inverter, wherein an input of the delay circuit is the clock input, and wherein a first inverter of the delay circuit is coupled to receive a test input signal and is configured to force a first logical state on an output of the first inverter responsive to an assertion of the test input signal. | 11-04-2010 |
20100308790 | APPARATUS AND METHOD FOR TESTING DRIVER WRITEABILITY STRENGTH ON AN INTEGRATED CIRCUIT - An apparatus and method for testing driver write-ability strength on an integrated circuit includes one or more drive detection units each including a number of drivers. At least some of the drivers may have a different drive strength and each may drive a voltage onto a respective driver output line. Each drive detection unit may include a number of keeper circuits, each coupled to a separate output line and configured to retain a given voltage on the output line to which it is coupled. Each detection unit may also include a number of detection circuits coupled to detect the drive voltage on each of the output lines. In one implementation, the drive voltage appearing at the output line of each driver may be indicative of that the driver was able to overdrive the voltage being retained on the output line to which it is coupled by the respective keeper circuits. | 12-09-2010 |
20100308887 | APPARATUS AND METHOD FOR TESTING LEVEL SHIFTER VOLTAGE THRESHOLDS ON AN INTEGRATED CIRCUIT - An apparatus and method for testing level shifter threshold voltages on an integrated circuit includes one or more level shifter modules each including a number of level shifter circuits. Each level shifter circuit may be coupled to a first and a second voltage supply. Each level shifter circuit may also receive an input signal that is referenced to the first voltage supply, and to generate an output signal that is referenced to the second voltage supply. In addition, each level shifter module may include detection logic that may detect an output value of each of the level shifter circuits. The control circuit may be configured to iteratively change the voltage output from one of the voltage supplies, and maintaining a voltage on the other voltage supply while the input signal is provided to the level shifter circuits. The detection logic may capture the output value upon each change in voltage. | 12-09-2010 |
20100322026 | MECHANISM FOR MEASURING READ CURRENT VARIABILITY OF SRAM CELLS - A mechanism for measuring the variability of the read current of SRAM cells on an integrated circuit includes the integrated circuit having an SRAM array including a plurality of SRAM cells. The integrated circuit may also include a selection circuit configured to select a particular SRAM cell in response to a selection input. An oscillator circuit such as a ring oscillator, for example, on the integrated circuit may be configured to oscillate at a frequency that is dependent upon a read current of a selected SRAM cell during operation in a first mode. A frequency determining circuit that is coupled to the oscillator circuit may be configured to output a value corresponding to the frequency of oscillation of the oscillator circuit. | 12-23-2010 |
20110012643 | APPARATUS AND METHOD FOR TESTING SENSE AMPLIFIER THRESHOLDS ON AN INTEGRATED CIRCUIT - An apparatus and method for testing sense amplifier threshold voltages on an integrated circuit includes one or more sense amplifier modules each including a number of sense amplifier circuits, a voltage generator unit, and detection logic. The voltage generator unit may select a differential voltage to supply to at least some of the sense amplifier circuits, and each sense amplifier circuit may be configured to generate an output value that is dependent upon the applied differential voltage in response to receiving an enable signal. The detection logic may detect and capture an output value of each of the sense amplifier circuits. In one implementation, the voltage generator unit may iteratively select a different differential voltage in response to a control input. Accordingly, the detection logic may capture the output value of the sense amplifiers after each change in differential voltage. | 01-20-2011 |
20110202809 | Pulse Flop with Enhanced Scan Implementation - In an embodiment, a clocked storage device such as a pulse flop is provided. The pulse flop includes a latch coupled to receive a scan data input to the pulse flop. The latch receives the scan data input during one of the phases of the clock, and retains the received input during the other phase. The other phase is the phase in which the pulse to the pulse flop occurs. Thus, when scan data is captured in the pulse flop, the latch at the next pulse flop in the chain may be closed and may prevent a race condition in propagating the scan data. | 08-18-2011 |
20110257954 | Versatile Method and Tool for Simulation of Aged Transistors - In an embodiment, an aging analysis tool may be configured to identify transistors that are expected to experience aging effects according to worst case stress vectors and/or designer identified worst case conditions. The aging analysis tool may modify a representation of the circuit (e.g. a netlist), replacing the identified transistors with aged transistors (e.g. by modifying parameters of the transistors in the netlist). The aging analysis tool may process the modified netlist over a range of conditions at which the circuit is expected to operate, to ensure that the design meets specifications after aging. The process may be repeated until the aged design meets specifications (with circuit modifications made by the designer to improve the design). | 10-20-2011 |
20110285431 | Self-Gating Synchronizer - A synchronizer circuit for transferring data from a source clock domain to a target clock domain. A first latch in the target clock domain may capture a data value corresponding to current data received from the source clock domain. Under certain conditions, the first latch may enter into a metastable, or undefined logic state. A second latch may remain stable, and store a previous value corresponding to data that has most recently been transferred from the source clock domain to the target clock domain. The respective values output by the two latches may be compared by a detection circuit, and a value derived from the output value of the first latch and corresponding to the current data may be written to an output latch if the current data differs from the stored previous value. The detection circuit may also provide a defined logical value to the output latch even if the first latch is in a metastable state. | 11-24-2011 |
20110289372 | Scan Latch with Phase-Free Scan Enable - A number of scan flops clocked by a master clock may be used to constructing a scan chain to perform scan tests. During a scan test, data appearing at the regular data input of each scan flop may be written into a master latch of the scan flop during a time period when the scan control signal is in a state corresponding to a capture cycle. A slave latch in each scan flop may latch a value appearing at the regular data input of the scan flop according to a narrow pulse triggered by the rising edge of the master clock when the scan control signal is in the state corresponding to the capture cycle. The slave latch may latch the data provided by the master latch according to a wide pulse triggered by the rising edge of the master clock when the scan control signal is in a state corresponding to a shift cycle. This may permit toggling the scan control signal during either a high phase or a low phase of the master clock, and may also enable testing the pulse functionality of each scan flop. | 11-24-2011 |
20120112736 | APPARATUS AND METHOD FOR TESTING DRIVER WRITEABILITY STRENGTH ON AN INTEGRATED CIRCUIT - An apparatus and method for testing driver write-ability strength on an integrated circuit includes one or more drive detection units each including a number of drivers. At least some of the drivers may have a different drive strength and each may drive a voltage onto a respective driver output line. Each drive detection unit may include a number of keeper circuits, each coupled to a separate output line and configured to retain a given voltage on the output line to which it is coupled. Each detection unit may also include a number of detection circuits coupled to detect the drive voltage on each of the output lines. In one implementation, the drive voltage appearing at the output line of each driver may be indicative of that the driver was able to overdrive the voltage being retained on the output line to which it is coupled by the respective keeper circuits. | 05-10-2012 |
20120215516 | IR Drop Analysis in Integrated Circuit Timing - In one embodiment, an IR drop analysis methodology may include characterizing standard cells without including power parasitic impedances, extracting the power parasitic impedances for the standard cells, and characterizing the standard cells with the power parasitic impedances. A set of timing parameters (such as minimum delays and maximum delays through the cells) may be generated from each characterization. The methodology may include comparing the timing parameters from each characterization, and identifying cells for which additional design effort should be expended to improve the power supply grid (e.g. to reduce the power parasitic impedances). For example, a margin may be budgeted for speed loss (delay increase) due to IR drop. If the difference in the timing parameters exceeds the margin, additional design effort may be warranted. | 08-23-2012 |
20120274357 | Reducing Narrow Gate Width Effects in an Integrated Circuit Design - A method for reducing narrow gate width effects in an integrated circuit includes finding the smallest transistor channel widths that are larger than the minimum width for the technology for library cells that produce logic blocks that meet timing constraints while using the least amount of power and have the smallest possible area. The method may include characterizing a device library while varying process, voltage and temperature parameters, and synthesizing an HDL representation of a functional logic block including cells from the device library. The method may also include determining whether timing, area, and power values of the functional logic block are within a predetermined range. In response to the timing, area, and power values not being within the predetermined range, iteratively increasing the channel width of at least a portion of the transistors of at least one of the cells in the device library. | 11-01-2012 |
20130055191 | Method and Software Tool for Analyzing and Reducing the Failure Rate of an Integrated Circuit - A software tool and method for analyzing the reliability or failure rate of an integrated circuit (IC) are disclosed. The IC may include a plurality of circuit designs, and the software tool and method may aid a designer of the IC in determining a reliability rating of the IC based on reliability ratings of transistors or other circuit devices used in the circuit designs. In particular, the IC may include one or more circuit designs that have multiple instances within the IC (i.e., the same circuit design is instantiated multiple times), and the software tool and method may take into account the multiple instances when determining the reliability rating of the IC. | 02-28-2013 |
20130067292 | Scan Latch with Phase-Free Scan Enable - A number of scan flops clocked by a master clock may be used to constructing a scan chain to perform scan tests. During a scan test, data appearing at the regular data input of each scan flop may be written into a master latch of the scan flop during a time period when the scan control signal is in a state corresponding to a capture cycle. A slave latch in each scan flop may latch a value appearing at the regular data input of the scan flop according to a narrow pulse triggered by the rising edge of the master clock when the scan control signal is in the state corresponding to the capture cycle. The slave latch may latch the data provided by the master latch according to a wide pulse triggered by the rising edge of the master clock when the scan control signal is in a state corresponding to a shift cycle. This may permit toggling the scan control signal during either a high phase or a low phase of the master clock, and may also enable testing the pulse functionality of each scan flop. | 03-14-2013 |