Seiko Instruments Inc

Sii Semiconductor Corporation

Ablic Inc.

Masakazu Sugiura

Tsutomu Tomioka

Atsushi Igarashi

Hideyuki Sawai

Nao Otsuka

Masahiro Mitani

Takashi Imura

Toshiyuki Tsuzaki

Manabu Fujimura

Yuji Shiine

Kosuke Takada

Fumihiko Maetani

Takao Nakashimo

Yuji Kobayashi

Tadakatsu Kuroda

Daisuke Okano

Naohiro Hiraoka

Daisuke Yoshioka

Hiroki Chuman

Yoshikazu Kurusu

There is provided a reference voltage circuit which includes a depletion type transistor and an enhancement type transistor. At least one of the depletion type transistor and the enhancement type transistor is formed from a plurality of transistors and the reference voltage circuit is arranged in the form of a common centroid (common center of mass) to avoid the influence of a characteristic fluctuation due to stress from the resin encapsulation of a semiconductor device or the like.

Reference voltage circuit including depletion type and enhancement type transistors in a common centroid arrangement

A voltage regulator includes an error amplifier circuit which controls a gate voltage of an output transistor, an overcurrent protection circuit which prevents an overcurrent of the output transistor, and a protection circuit which detects a negative voltage of an output terminal and controls a gate voltage of the output transistor to suppress an overcurrent. The protection circuit includes a MOS transistor which controls the gate voltage of the output transistor, a clamp circuit connected to a gate of the MOS transistor, a semiconductor element having an N-type region connected to the clamp circuit, and a parasitic bipolar transistor constructed from an N-type region connected to the output terminal as an emitter, a P-type substrate as a base, and the N-type region of the semiconductor element as a collector.

Voltage regulator

A source-grounded amplifier circuit supplied with a signal of an error amplifier circuit, and an output transistor supplied with a control voltage of the source-grounded amplifier circuit are provided. The source-grounded amplifier circuit has, in a signal path, a current limiting circuit including a cascode circuit controlled by a voltage having a positive temperature coefficient. A voltage regulator capable of reducing a dropout voltage of an output voltage without exceeding a gate breakdown voltage of the output transistor is provided.

Provided is a transconductance amplifier including a common-mode feedback circuit that does not affect an operation of the transconductance amplifier. The transconductance amplifier has a transconductance amplifier circuit configured to generate an output current based on an input voltage and a common-mode feedback circuit configured to determine a DC operating point of an output of the transconductance amplifier circuit. The common-mode feedback circuit has a plurality of level shift circuits configured to shift levels of input voltages to output the voltages, and are connected to control terminals of a plurality of transistors.

Transconductance amplifier

A current generation circuit includes: a current source circuit including a first transistor and a first resistor, and configured to output a first current based on a source voltage or a drain voltage of the first transistor and a resistance of the first resistor; a current control circuit including a voltage input terminal, a second transistor and a third transistor, and configured to output a second current based on a source voltage of the second transistor and a resistance of the third transistor; and an impedance circuit including a second resistor formed of a same resistive body as the first resistor and a fourth transistor diode-connected to the second resistor, and configured to generate a control voltage at the voltage input terminal by the first current and the second current, wherein the current generation circuit is configured to output a current based on the second current.

Current generation circuit

Provided is a differential amplification device reduced in DC offset voltage. The amplification device amplifies an input signal, and includes a chopper switch circuit which switches the polarity of the input signal between a normal phase and a reverse phase and outputs the input signal, a V-I conversion circuit which is connected to the chopper switch circuit, a capacitance circuit which is connected to the V-I conversion circuit to store electric charges supplied from the V-I conversion circuit, and an amplification circuit which is connected to the V-I conversion circuit to switch the polarity of an input signal between the normal phase and the reverse phase and amplify the input signal.

Differential amplification device

To provide an input circuit which avoids power supply voltage dependency of a threshold of the input circuit when an output signal is transited. There is provided an input circuit equipped with an input transistor and a current source connected in series between a first power supply and a second power supply. The input circuit is configured in such a manner that an input signal is inputted to a gate of the input transistor and a signal of a connection point between the input transistor and the current source is outputted as an output signal, and a current value of the current source is changed based on the output signal.

Input circuit

Provided is a level shift circuit capable of converting a negative voltage level as well as a positive voltage level. The level shift circuit includes a switching transistor between an input transistor and a load, the switching transistor including a gate connected to a voltage source, and an input negative voltage level is converted into a second negative voltage level based on a voltage of the voltage source and a threshold voltage of the switching transistor.

Level shift circuit

Provided are an amplifier circuit capable of reducing DC offset voltage without an increase in chip area and degradation in frequency characteristics, and a multipath nested miller amplifier circuit. The amplifier circuit includes a chopper switching circuit, a sampling circuit configured to sample an output signal from the chopper switching circuit, and a holding circuit configured to hold a signal output from the sampling circuit.

Amplifier circuit and multipath nested miller amplifier circuit

Provided is an overheat detection circuit configured to accurately detect a temperature of a semiconductor device even at high temperature and thus avoid outputting an erroneous detection result. The overheat detection circuit includes: a PN junction element, being a temperature sensitive element; a constant current circuit configured to supply the PN junction element with a bias current; a comparator configured to compare a voltage generated at the PN junction element and a reference voltage; a second PN junction element configured to cause a leakage current to flow through a reference voltage circuit at high temperature; and a third PN junction element configured to bypass a leakage current of the constant current circuit at the high temperature.

Overheat detection circuit and semiconductor device

Provided is an overheat detection circuit that is capable of quickly outputting an overheated state detection signal in an overheated state without outputting an unintended erroneous output caused by disturbance noise, such as momentary voltage fluctuations in the power supply. The overheat detection circuit includes: a temperature sensor; a comparison section; and a disturbance noise removal section configured to output an overheated state detection signal to an output section after a predetermined delay time has elapsed. The delay time is reduced in proportion to temperature.

To provide a voltage detection circuit which avoids unintentional on/off-control of an output transistor immediately after starting a power supply. A voltage detection circuit is configured to be equipped with a comparator which compares a detected voltage and a reference voltage, and an inverter which drives an output transistor, based on an output of the comparator and to supply the operating current of the inverter by a current source.

Voltage detection circuit

Provided is a reference voltage circuit capable of adjusting an arbitrary output voltage to have arbitrary temperature characteristics. The reference voltage circuit includes: a reference current generating circuit configured to convert a difference between forward voltages of a plurality of PN junction elements into current to generate a first current; a current generating circuit configured to use the first current generated by the reference current generating circuit to generate a second current; and a voltage generating circuit including a first resistive element and a second resistive element, the first resistive element being configured to generate a first voltage having positive temperature characteristics when the first current flows through the first resistive element, the second resistive element being configured to generate a second voltage having negative temperature characteristics when the first current and the second current flow through the second resistive element. The reference voltage circuit outputs a reference voltage obtained by adding the first voltage to the second voltage.

Reference-voltage circuit

Provided is a voltage regulator configured to suppress a fluctuation in output voltage even when a power supply voltage fluctuates, thereby realizing stable operation thereof. The voltage regulator includes a control circuit including a first input terminal connected to a drain of an output transistor, a second input terminal connected to a power supply terminal, an overshoot detection circuit connected to the first input terminal, and a power supply voltage detection circuit connected to the second input terminal, and being configured to cause a boost current to flow through an error amplifier circuit when an output voltage and a power supply voltage largely fluctuate with respect to a predetermined voltage.

Provided is a voltage regulator configured to suppress a variation of an output voltage so as to stably operate even when a power supply voltage varies. The voltage regulator includes a control circuit having an input terminal connected to a drain of an output transistor, and an output terminal connected to an error amplifier circuit. The control circuit is configured to cause a boost current to flow through an error amplifier circuit when the output voltage varies beyond a predetermined value.

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Chiba, Japan

Masakazu Sugiura