Renesas Electronics Corporation

Nec Electronics Corporation

Nec Corporation

Kenichi Kawakami

Masashi Kurokawa

Michimasa Yamaguchi

Tomoya Nishitani

A semiconductor integrated circuit includes a macro connected between a first power supply line and a second power supply line to drive a load, and a power-supply-noise cancelling circuit connected between an input and an output of the macro to generate a current for canceling one of a current flowing from the first power supply line to the output of the macro and a current flowing from the output of the macro to the second power supply line, on the basis of a potential difference between the input and the output of the macro. The macro and the power-supply-noise cancelling circuit are mounted in a same chip.

Semiconductor integrated circuit

A differential amplifier includes first and second current paths, each connected between first and second power supplies (PS) and respectively outputting first and second differential output signals. The first current path includes: first transistor, selectively interconnected between the first PS and a first output terminal, its gate receiving one differential input signal; second transistor, connected between the second PS and the first output terminal, its gate receiving the other differential input signal; and first switch circuit. The second current path includes: third transistor, selectively interconnected between the second PS and a second output terminal, its gate receiving one differential input signal; fourth transistor, connected between the first PS and the second output terminal, its gate receiving the other differential input signal; and second switch circuit. One of the first and second switch circuits is connected to the first PS and the other is connected to the second PS.

Differential amplifier

A differential amplifier including: 1st transistor that is connected between 1st power-supply terminal and 1st output terminal, and has a control terminal receiving one of the differential input signals; 2nd transistor that is connected between 2nd power-supply terminal and 1st output terminal, and has a control terminal receiving the other of the differential input signals; 1st switch that is connected between 1st power-supply terminal and 1st transistor; 3rd transistor that is connected between 2nd power-supply terminal and 2nd output terminal, and has a control terminal receiving one of the differential input signals; 4th transistor that is connected between 1st power-supply terminal and 2nd output terminal, and has a control terminal receiving the other of the differential input signals; 2nd switch that is connected between 2nd power-supply terminal and 3rd transistor. Drive state of 1st and 2nd switches are controlled by a control signal.

Provided is a semiconductor integrated circuit including: an output circuit connected between a power supply (VDD) and a ground (GND), having an input connected to an input terminal, and having an output connected to an output terminal; and a power-supply-noise cancelling circuit connected between the input terminal and the output terminal to generate a current that cancels a current flowing from the power supply (VDD) to the output terminal or a current flowing from the output terminal to the ground (GND), based on a potential difference between the input terminal and the output terminal.

A semiconductor device includes a pre-buffer for transferring a data signal on the basis of a first power supply voltage, a main buffer for amplifying and outputting the data signal transferred by the pre-buffer on the basis of a second power supply voltage different from the first power supply voltage, a switch unit for controlling a conductive state between the pre-buffer and the main buffer on the basis of a switch control signal, and a control circuit for generating the switch control signal for controlling the pre-buffer to set an output level of the pre-buffer to ground potential in accordance with transition of logical level of the switch control signal.

Semiconductor device having transfer gate between pre-buffer and main buffer

A driver circuit that prevents amplitude reduction at a high temperature comprises a differential pre-buffer circuitfor performing signal clamping by diodesandeach having a nonlinear voltage-current characteristic with respect to an input signal and a differential output circuitfor amplifying output signals of the differential pre-buffer circuit, for output. The driver circuit further includes a temperature characteristic compensation circuitfor controlling direct currents to be passed through the diodesandbased on a current to be passed through a diodehaving a voltage-current characteristic with the same temperature coefficient as those of the diodesand. A current related to constant currents Iand Iis supplied from the temperature characteristic compensation circuitas a current that cancels the temperature characteristic of a fall in forward voltages of the diodesand

Driver circuit

A periodic low current from an intermittent Low current generator 5 is used, and fluctuations of r1 and r10, c1 and c2, and I6 and I20, thus cancel one another. Thus, .omega..sub.0 is not fluctuated unless the oscillation frequency Tosc of a pulse wave generator OSC is fluctuated. Television and ratio audio ICs using an LPF filter do not require specific provision of any oscillator for a filter circuit, because they have an accurate oscillator. The oscillation frequency of the pulse wave generator OSC should be at least 20 times the pass band of the filter circuit.

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Kanagawa, Japan

Kenichi Kawakami