Abstract: A scan separator in a large scale integration device is made more extensive to suppress an increase in the circuit scale of the entire device. In one embodiment, a scan separator is provided for every two signal lines interconnecting two combinatorial circuit blocks. Each scan separator includes a selector and a flip flop for constituting a scan path. Another selector is provided for selecting one of the two signal lines. As an input selector signal for the selector that selects one of the two signal lines, data for switching controlling are used, which are transferred from a test input terminal over the scan path and latched by the flip flop. The data for switching controlling are initially transferred over the scan path to each flip flop. The selector that selects one of the two signal lines is switched in accordance with the switching controlling data stored in the flip flop. The switching controlling data may be interchanged to select the either of the two signal lines.

Abstract: A scan separator in a large scale integration device is made intensive to suppress the circuit scale of the entire device from increasing. A scan separator is provided for every two signal lines interconnecting two combinatorial circuit blocks. Each scan separator includes one selector, a flip flop for constituting a scan path, and another selector for selecting one of the two signal lines. As an input selector signal for the other selector, data for switching controlling are used, which are transferred from a test input terminal over the scan path and latched by the flip flop. The data for switching controlling are initially transferred over the scan path to each flip flop. The other selector is switched in accordance with the switching controlling data stored in the flip flop to select one of the two signal lines. The switching controlling data may be interchanged to select the other signal line.

Abstract: The present invention provides a LSI being capable of testing a signal path between two circuit blocks by a scan isolation test. A scan isolation circuit 30-1 includes a first selector 31 alternating a held signal S33 or a signal SA from circuit block 10A and outputting the alternated signal thereof as signals 31, and a second selector 32 selecting the signal S31 or one signal from the signal SAm from outside or the previous-stage signal S33. Further, the held signal S33 held in the FF 33 thereof is supplied to the selector 31 and the next-stage scan isolation circuit 30-2, connecting the FF 33 to the output terminal. During the test therein, since the signal SA is held through the selectors 31 and 32, the signal path between the circuit blocks 10A and 10B can be conducted.

Abstract: A semiconductor integrated circuit has a plurality of signal paths and a plurality of scan separation circuits. Each scan separation circuit is provided on each signal path. Each scan separation includes a first selector and a second selector. The semiconductor integrated circuit also includes a first circuit block and a second circuit block. The first selector switches between a signal from the first circuit block and an output signal from a flip-flop provided in the scan separation circuit, and supplies the selected signal to the second circuit block. The selected signal is also supplied to the second selector. The second selector selects the signal from the first selector or a signal from outside (or a test signal supplied from an earlier-stage scan separation circuit). The output of the second selector is connected to a flip-flop. The test signal held by the flip-flop is supplied to the first selector and to a subsequent-stage scan separation circuit.

Abstract: A vehicle headlamp having a projector-type light source assembly capable of emitting a highly coherent light beam. In order to make the headlamp appear larger than the light source assembly, a lamp housing is provided which is much larger in size than the light source assembly mounted therein, with the consequent provision of an annular space around the light source assembly within the lamp housing. Disposed in this annular space is an outline expander plate of transparent material having a multiplicity of minute cavities of cone shape formed in its rear face. The outline expander plate transmits by internal total reflection the light incident edgewise thereon. While so traveling through the outline expander plate, the light is reflected by the surfaces of the conical cavities generally in the forward direction of the headlamp, thereby making the complete surface area of the headlamp appear glowing.