A flip flop includes a master latch and a slave latch. The master latch includes a delay circuit configured to receive a clock signal and generate a first internal signal, and is configured to generate an internal output signal by latching a data signal based on the first internal signal. The slave latch is configured to generate a final signal by latching the internal output signal. The delay circuit is further configured to generate the first internal signal by delaying the clock signal by a delay time when the clock signal has a first logic level and generate the first internal signal based on the data signal when the clock signal has a second logic level.

A circuit comprises: a bit-flipping signal generation device comprising a storage device and configured to generate a bit-flipping signal based on bit-flipping location information, the storage device configured to store the bit-flipping location information for a first number of bits, the bit-flipping location information obtained through a fault simulation process; a pseudo random test pattern generator configured to generate test patterns based on the bit-flipping signal, the pseudo random test pattern generator comprising a register configured to be a linear finite state machine, the register comprising storage elements and bit-flipping devices, each of the bit-flipping devices coupled to one of the storage elements; and scan chains configured to receive the test patterns, wherein the bit-flipping signal causes one of the bit-flipping devices to invert a bit of the register each time a second number of test patterns is being generated by the pseudo random test pattern generator during a test.

A semiconductor device comprises a plurality of memory elements, test control circuitry, and a testing interface. The test control circuitry is configure to determine that one or more clock signals associated with the memory elements have been stopped and generate a scan clock signal based on the determination that the one or more clock signals have been stopped. The test control circuitry is further configured to communicate the scan clock signal to the memory elements. The testing interface is configured to communicate test data from the memory elements. In one example, the test data is delimited with start and end marker elements. The semiconductor device is mounted to a circuit board and is communicatively coupled to communication pins of the circuit board.

A low power flip-flop includes first to fourth signal generation circuits and an inverter. The first signal generation circuit receives the clock signal, the data input signal, and a first internal signal that is an output of the second signal generation circuit and generates a second internal signal. The inverter receives the first internal signal and generates an inverted first internal signal. The second signal generation circuit receives the first internal signal and the output signal that is an output of the third signal generation circuit, and generates the inverted output signal. The third signal generation circuit receives the clock signal and the inverted output signal and generates the output signal. The fourth signal generation circuit receives the inverted first internal signal, the second internal signal, and the clock signal and generates the first internal signal.

A combinational circuit block has input pins configured to receive input digital signals and output pins configured to provide output digital signals as a function of the input digital signals received. A test input pin receives a test input signal. A test output pin provides a test output signal as a function of the test input signal received. A set of scan registers are selectively coupled to either the combinational circuit block or to one another so as to form a scan chain of scan registers serially coupled between the test input pin and the test output pin. The scan registers in the set of scan registers are clocked by a clock signal. At least one input register is coupled between the test input pin and a first scan register of the scan chain. The at least one input register is clocked by an inverted replica of the clock signal.

An integrated circuit includes a flip-flop circuit and a gating circuit. The flip-flop circuit is arranged to receive an input data for generating a master signal during a writing mode according to a first clock signal and a second clock signal, and to output an output data according to the first clock signal and the second clock signal during a storing mode. The gating circuit is arranged for generating the first clock signal and the second clock signal according to the master signal and an input clock signal. When the input clock signal is at a signal level, the first clock signal and the second clock signal are at different logic levels. When the input clock signal is at another signal level, the first clock signal and the second clock signal are at a same logic level determined according to a signal level of the master signal.

A system, comprising: a plurality of first latches; a compressor circuit, coupled to the first latches, configured to compress an first signal having X bits from the first latches to a second signal having Y bits, wherein X and Y are positive integers and X is larger than Y; and at least one second latch, coupled to the compressor circuit, configured to receive the second signal to generate a scan output, wherein each of the first latches and the second latch forms a D flip flop. The system outputs the first signal but none of the scan output in a normal mode, and outputs the scan output but none of the first signal in a test mode.

An Integrated Circuit (IC) includes a storage element and control circuitry. The control circuitry is configured to select, responsively to a scan-enable control, between a functional-data input and a scan-data input to serve as an input to the storage element, to selectively disable toggling of an output of the storage element, responsively to a clock-enable control, by gating a clock signal provided to the storage element, and, while the clock-enable control indicates that the output of the storage element is to be disabled from toggling, to select the input of the storage element to be the scan-data input.

One exemplary embodiment describes an integrated circuit, comprising a multiplicity of scan flip-flops, a multiplicity of ring oscillator circuits, wherein each ring oscillator circuit comprises a chain of logic gates comprising a plurality of logic gates connected in succession, an input multiplexer for the chain, and a feedback line from an output connection of the last logic gate of the chain to a data input connection of the input multiplexer. Each ring oscillator circuit is assigned a scan flip-flop group that contains at least one of the multiplicity of scan flip-flops. The input multiplexer of the ring oscillator circuit is controlled depending on a control bit stored by the at least one scan flip-flop of the scan flip-flop group assigned to the ring oscillator circuit such that the input multiplexer outputs an output bit fed back via the feedback line to the first logic gate of the chain or that the input multiplexer outputs a input bit that is to be processed by the chain to the first logic gate of the chain. The ring oscillator circuits are assigned different scan flip-flop groups.

A semiconductor device of the embodiment includes a plurality of scan chains, a shift clock control circuit, and a shift clock generation circuit. The plurality of scan chains each include a plurality of scan flip-flops. The shift clock control circuit outputs, to each of the plurality of scan chains, a control signal that non-inverts or inverts a scan clock signal. The shift clock generation circuit is provided to each of the plurality of scan flip-flops and generates a non-inverted scan clock signal or an inverted scan clock signal based on the control signal, the non-inverted scan clock signal being obtained by non-inverting the scan clock signal, the inverted scan clock signal being obtained by inverting the scan clock signal.