Freescale Semiconductor,inc.

Freescale Semiconductors Inc.

Gaurav Goyal

Amol Agarwal

Naman Gupta

Bipin B Malhan

Abhishek Mahajan

Reecha Jajodia

Rohit Goyal

Umesh Chandra Lohani

Ateet Mishra

Gaurav Gupta

Kumar Abhishek

Sidhartha Taneja

Ashis Maitra

Syed Shakir Iqbal

Mohit Parnami

A scannable flip-flop circuit and method for low power scan operation are provided. The scannable flip-flop includes a flip-flop for receiving an input signal, and for generating a flip-flop output signal. The scannable flip-flop also includes a voltage selection circuit coupled to the flip-flop. The voltage selection circuit supplies a first voltage to the flip-flop during a first state of a voltage selection signal, and supplies a second voltage to the flip-flop during a second state of the voltage selection signal. A series of scannable flip-flops may be arranged in a scan chain for testing during a scan test mode.

Scannable flip-flop and low power scan-shift mode operation in a data processing system

Flip-flop cells that enable time borrowing during the design of the IC to improve setup times while avoiding introducing meta-stability, and alternatively to avoid hold time violations. The flip-flop cells are connected with logic cells in functional data paths. The flip-flop cell has a clock signal controlling both its input and output. A selective delay cell selectively delays either a data signal input to the flip-flop cell or the clock signal controlling the flip-flop cell. The selectively delayed signal adjusts the timing (setup, hold and clock-to-output) of the data path.

Flip-flop cell with configurable delay

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 single power supply level shifter has first and second inverters in tandem that invert an input signal from a first voltage domain and provide a first inverted signal and an output signal in a second voltage domain. A charging control circuit charges a capacitor towards the second voltage when the input signal is high, and conducts a discharge current from the capacitor during a transition of the input signal from high to low to accelerate a corresponding transition of the first inverted signal from low to high. A third inverter controls a current reduction transistor in series with the first inverter, and a third control transistor connected between the input and the charging control circuit to accelerate the flow of discharge current during the transition of the input signal from high to low.

Single power supply level shifter

An integrated circuit having reduced power consumption includes a clock-gating cell, a transistor and a flip-flop. The clock-gating cell receives a dynamic enable signal, generates a latched-enable signal and gates a clock signal provided to the flip-flop. The flip-flop includes first and second latches. The transistor receives an inverted latched-enable signal from the clock-gating cell and switches ON or OFF based on the logic state of the inverted latched-enable signal. The transistor provides a voltage signal to the flip-flop circuit based on the state of the flip-flop in order to control the state of the flip-flop, which reduces power consumption of the integrated circuit.

Low leakage flip-flop circuit

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 Gray code counter has multiple two-bit Gray code counter modules, clock gated integrated cells (CGICs), and a parity bit generator. The CGICs gate clock signals provided to the two-bit counter modules, which reduces dynamic power consumption. The parity bit generator generates a parity bit that indicates a count of binary ones in a counting state.

Modular gray code counter

A scan flip-flop for generating an output signal based on a first input signal, a clock signal, a test input signal, a Launch On Shift (LOS) signal, a test enable signal, and a reset signal includes a logic circuit, a multiplexer and a flip-flop circuit. The logic circuit receives an inverted clock signal, the test enable signal, a intermediate test enable signal, and the LOS signal, and generates an intermediate output signal that is an inherent LOS scan enable signal. The multiplexer receives the test input signal and the intermediate output signal, and outputs the test input signal. The flip-flop circuit receives the test input signal as a second input signal, the clock signal, and the reset signal, and generates the output signal.

Scan flip-flop circuit with LOS scan enable signal

Spare gate cells for inclusion in an integrated circuit have multiple inputs and outputs and are capable of selectively performing, concurrently, multiple logic functions on signals appearing at the inputs. Selection of required logic functions depends on the connections of at least one of the inputs of the spare cell. One of the outputs is fed back to an input of the spare gate cell to provide certain functionality while other outputs are set to a fixed logical value. The spare gate cell may be configured to perform NOR, OR and inverter operations on inputs simultaneously.

Spare gate cell for integrated circuit

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 single supply level shifter circuit for shifting the voltage level of an input voltage includes a voltage translation stage and a driver stage. The voltage translation stage receives the input voltage and a voltage supply and generates a first voltage. When a magnitude of the input voltage is LOW, the first voltage is LOW. The first voltage is provided to the driver stage, which inverts the first voltage to generate an output voltage that is at a voltage supply (Vdd) level, thereby level shifting the input voltage.

Level shifter circuit

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 dual supply bidirectional level shifter performs voltage level shifting in two directions, low to high and high to low. A feedback control branch and a control stage inverter are provided that reduce leakage power and allow for low delay time while also allowing for a small circuit footprint.

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Dehradun, India

Gaurav Goyal