Fujitsu Corporation

Socionext Inc.

Fujitsu Microelectronics Limited

Fujitsu Semiconductor Limited

Tomohiko Koto

Toshiya Suzuki

Osamu Uno

Ryo Shibata

Kyota Shimizu

Kenichi Konishi

A drive assist circuit includes a pulse generation circuit which outputs a pulse to control an assist operation when an assist signal makes a first transition corresponding to a transition of a gate signal from a high level to a low level. The pulse generation circuit includes a delay circuit provided in one of two inputs of a logic gate. The delay circuit is configured such that a delay is greater when an input makes a transition corresponding to the first transition of the assist signal, as compared to a case where the input makes a transition corresponding to an inverse of the first transition.

Output circuit

An output circuit includes: a first p-type transistor having a source connected to VDDH and a gate to which an input signal is fed; and a second p-type transistor having a source connected to the drain of the first p-type transistor, a drain connected to an output terminal, and a gate connected to a first node. A capacitor has one terminal to which the input signal is fed and the other terminal connected to the first node. A first n-type transistor has a source connected to VDDL, a drain connected to the first node, and a gate to which a signal corresponding to the input signal is fed. A second n-type transistor has a source and a gate both connected to VDDL and a drain connected to the first node.

A level conversion circuit includes: first P-ch and N-ch transistors and second P-ch and N-ch transistors respectively connected in series between first and second power sources; third and fourth P-ch transistors respectively connected between the gates of the second and first P-ch transistors and the drain of the first and second P-ch transistors; and fifth and sixth P-ch transistors respectively connected between the gates of the second and first P-ch transistors and a third power source, wherein differential input signals are applied to the gates of the first and second N-ch transistors, a bias voltage is applied to the gates of the third and fourth P-ch transistors, the gate of the fifth and sixth P-ch transistors are respectively connected to connection nodes of the first P-ch and N-ch transistors the second P-ch and N-ch transistors.

Level converter circuit

A level converter comprising an input circuit, coupled to a low power source and a first high power source, which generates a complementary first signal and second signal; and a shift circuit that outputs an output signal generated by shifting a voltage level of the input signal, the shift circuit including: a latch circuit having: a first inverter circuit provided in a first path between a second high power source and the low power source; and a second inverter circuit provided in a second path between the second high power source and the low power source, wherein the latch circuit is formed by coupling an input terminal and an output terminal of the first inverter circuit and the second inverter circuit; a first transistor coupled to the first path; and a second transistor coupled to the second path.

Level converter

A semiconductor device includes a circuit section having an output impedance which changes in accordance with a switching signal for switching between drive capabilities, and transforming an input signal into an output signal in accordance with the output impedance, a reference voltage generating section generating a reference voltage in accordance with the switching signal and the input signal, and a comparing section comparing a voltage of the output signal to the reference voltage.

Semiconductor device and method for controlling thereof

A method for calculating a tolerable value for simultaneous switching noise in an input/output circuit having a differential input supplied with a power supply voltage. The method includes providing an input/output circuit having a differential input unit with a pulse signal of a predetermined duty ratio, setting a tolerable range for the duty ratio of the output signal of the input/output circuit with respect to the pulse signal, changing the power supply voltage supplied to the differential input unit of the input/output circuit, measuring the duty ratio of the output signal corresponding to the voltage change, comparing the measured duty ratio with the tolerable range, and calculating a tolerable value for the simultaneous switching noise.

Method for calculating tolerable value for fluctuation in power supply voltage and method of testing

A semiconductor integrated circuit for decreasing level fluctuation in an output signal of a level conversion circuit. The level conversion circuit has a pair of series-connected transistors including a first MOS transistor and a second MOS transistor and a further pair of series-connected transistors including a third MOS transistor and a fourth MOS transistor. The level conversion circuit generates a first output signal from a node connecting the first and second MOS transistors and a second output signal from a node connecting the third and fourth transistors. A differential amplification circuit functions in accordance with the first and second output signals. The first and fourth MOS transistors each have a gate for receiving a first input signal. The second and third MOS transistors each have a gate for receiving a second input signal having a phase inverted from the phase of the first input signal.

Semiconductor integrated circuit and level conversion circuit

An input circuit for preventing the application of a voltage exceeding a transistor withstand voltage when the input circuit is switched to a standby state. The input circuit includes a first differential amplification circuit powered by a first power supply to amplify a first input signal and generate a second input signal. A level shift circuit is powered by the first power supply to generate a shifted input signal from the second input signal. A second differential amplification circuit is powered by a second power supply to amplify the shifted input signal and generate an amplified signal. A current control circuit selectively switches the input circuit between activated and standby states. A first circuit charges or discharges the level shift circuit so that voltage of the shifted input signal is less than or equal to voltage of the second power supply when switched to the standby state.

Input circuit

A semiconductor integrated circuit having a latch including a data input terminal and a timing input terminal, has a first input terminal connected to the latch data input terminal and a second input terminal connected to the latch timing input terminal. A delay circuit, connected between the first and second input terminals, receives a test signal being supplied to a selected one of the first and second input terminals and supplies a delayed test signal to the nonselected one of the first and second input terminals.

Semiconductor integrated circuit device with test circuit

A semiconductor memory device includes a memory circuit from which data is read in correspondence with a first reference clock signal. A multiplexer outputs the data read from the memory circuit in correspondence with the second reference clock signal. A comparison determination circuit receives the data read from the memory circuit via the multiplexer and compares the read data with an expected data value in correspondence with the second reference clock signal to generate determination result data.

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Kasugai, Japan

Tomohiko Koto