Freescale Semiconductor,inc.

Nxp Usa, Inc.

Amol Agarwal

Gaurav Goyal

Rohit Kumar Sinha

Abhishek Mahajan

Vandana Sapra

Garima Sharda

Stefan Doll

Andreas Lentz

Naman Gupta

Sidhartha Taneja

Reecha Jajodia

Himanshu Mangal

Harkaran Singh

Sumeet Aggarwal

Sabaa Sandhu

Pratyush Pranav Joshi

Love Gupta

Kapil Narula

Sunit K Bansal

A glitch detector includes a metastability detector circuit, a reference storage circuit, and a pattern comparison circuit. The metastability detector circuit is configured to generate state signals at each cycle of the clock signal. The reference storage circuit is configured to store a logic state of each state signal based on a delayed version of the clock signal, and generate reference signals. A logic state of each reference signal is equal to a logic state of a corresponding state signal generated during a previous cycle of the clock signal. The pattern comparison circuit is configured to receive the state signals generated during a current cycle of the clock signal, the reference signals, and first and second values, and generate clock and voltage glitch signals based on first and second patterns that are associated with the state signals generated during the current cycle and the reference signals, respectively.

Glitch detector

A clock control system for a scan chain generates two clock signals. During a shift phase of a testing mode of the scan chain, one clock signal is an inverted version of the other clock signal. The clock control system provides the clock signal and the inverted clock signal to two different scan flip-flops of the scan chain, respectively. Each of the two scan flip-flops performs a flip-flop operation when the received clock signal transitions from a de-asserted state to an asserted state. Thus, the two flip-flop operations are mutually exclusive during the shift phase. As a result, a dynamic voltage drop across the scan chain during the shift phase is reduced.

Clock control system for scan chains

A fixed-width pulse generator includes a metastability detector circuit, a delay signal generator, and a combinational logic circuit. The metastability detector circuit is configured to receive a trigger signal and generate state detection signals. The delay signal generator is configured to receive the state detection signals and the trigger signal, and delay the trigger signal by two different delay values to generate two different delayed signals. One of the delay values is based on the state detection signals. The combinational logic circuit is configured to receive the two delayed signals and an error signal, and generate a fixed-width pulse that remains constant over process, voltage, and temperature variations.

Fixed-width pulse generator

An n-bit counter is formed from cascading counter sub-modules. The counter includes combinatorial control logic coupled to a lower-order counter sub-module. The control logic includes a clock-gating integrated cell arranged to clock gate at least one higher-order counter sub-module dependent on a logical combination of outputs of the lower-order counter sub-module and to provide a multi-cycle path for resolution of a logical combination of outputs of any subsequent cascaded counter sub-modules. The control logic does not include any intervening memory device between the lower-order counter sub-module and the clock-gating integrated cell for use in determining a later control logic output.

Low power digital self-gated binary counter

A signal delay cell for use in resolving hold time violations in an IC has a first multiplexer having a first functional data input node and a scan data input node TI and a second multiplexer having a second functional data input node, a second input node connected to the output of the first multiplexer and a flip-flop module. The propagation of a data input signal applied to the first multiplexer is delayed, and the hold margin of the flip-flop module is increased by transit through the first multiplexer. The signal delay cell is available to replace a flip-flop having a scan data hold problem, and also for use in solving a functional data violation in the same or another cell.

Signal delay flip-flop cell for fixing hold time violation

A scan flip-flop includes a multiplexer, a flip-flop, and a logic circuit. The flip-flop includes a transmission gate that has two sets of clock-controlled transistors. The combined width of the clock-controlled transistors in a set equals the width of the single transistor commonly used in known scan flip-flop circuits. The logic circuit inhibits the clock signal from reaching one transistor of each set during scan mode, which reduces power consumption without sacrificing speed of operation.

Scan flip-flop

An n-bit counter is formed from cascading counter sub-modules. The counter includes combinatorial control logic coupled to a lower order counter sub-module. The control logic is arranged to clock gate at least one higher order counter sub-module dependent on a logical combination of outputs of the lower order counter sub-module and where the control logic uses pipelining to store at least one previous control logic output for use in determining a later control logic output.

Digital self-gated binary counter

A system for generating a gated clock signal includes an AND gate and a clock gating cell. The AND gate receives a reset signal and an input clock signal and generates a clock signal that is provided to a clock input terminal of the clock gating cell. The clock gating cell generates a gated clock signal based on an input signal and the clock signal. Gating the clock input to a latch allows a means for conserving power.

System for generating gated clock signals

A flip-flop circuit includes a data input, a clock input for receiving a clock signal having active edges and inactive edges, a data output, an input circuit, a pulse generator, and a latch. The input circuit sets first and second nodes to different initial logic states in response to an inactive edge of the clock signal, and selectively changes the logic state of either the first node or the second node in response to a pulse input signal to control the state of a third node, such that the selection depends on the logic state of the data input. The pulse generator circuit enables the pulse input signal in response to an active edge of the clock signal, and disables the pulse input signal in response to detecting the change in the initial logic state of either the first node or the second node. The latch stores a data output signal for output at the data output, the data output signal depending on the logic state of the third node.

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Amol Agarwal