Fujitsu Corporation

Hiroyuki Tsunoi

Eiji Sugiyama

Motohiro Seto

Yasunori Kanai

Kazumasa Nawata

Toshiaki Sakai

Taichi Saitoh

Takayuki Tsuru

Hiroki Yada

Satoru Sudo

Naoyuki Ando

Hisayosi Ooba

A logic circuit in which first and second transistors are connected in series between high and low potential power sources with the middle point of the series connection used as the output terminal; A same- and inverse-phase signal generating unit is provided connected between the high and low potential power sources in parallel with the first and second transistors for generating same- and inverse-phase signals based on the single input signal output from the logic circuit. A transient signal generating unit is provided for generating transient large current signals at the rise time of the inverse-phase signals and generating transient cut-off signals at the fall time of the inverse-phase signals. The series connected first transistor is driven and controlled based on the regular-phase signals, while the second transistor is driven and controlled based on the transient large current signal and transient cut-off signal, thus producing an inverse-phase output by a simple circuit construction.

Logic circuit having sharper falling edge transition

A latch circuit has two complementary hold loops therein for improving noise tolerance. The latch circuit includes a first gate for receiving a data and a first clock signal and outputting a first signal in response to a change in the clock signal. A second gate receives a second clock signal having an inverted polarity to that of the first clock signal. A third gate is operatively connected to output terminals of the first and second gates and outputs a first latch output. The latch circuit also includes a first hold line which supplies the first latch output to the second gate and a second hold line which supplies a second latch output of the latch circuit having an inverted polarity to that of the first latch output to the second gate. The second gate may have an inverted input terminal receiving the second latch output.

Latch circuit having two hold loops

In a master-slave type flip-flop circuit including a normal function in a normal mode for flip/flop operation and a scanning function in a scanning mode for testing an integrated circuit, the master-slave type flip-flop circuit comprises: a master stage having a first pair of differential transistors for taking in data, a second pair of differential transistors for latching data taken in to the first pair of differential transistors, a third pair of differential transistors for taking in scanning data, and a fourth pair of differential transistors for activating the second and third pair of differential transistors in the scanning mode; and a slave stage having a first pair of differential transistors for taking in data from the master stage, a second pair of differential transistors for latching data taken in to the first pair of differential transistors, a third pair of differential transistors for latching scanning data, and a fourth pair of differential transistors for activating the first and third pair of differential transistors in the scanning mode.

Master-slave type flip-flop circuit

Growing community of inventors

Yokohama, Japan

Hiroyuki Tsunoi