Abstract: 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.

Abstract: Provided is a voltage regulator capable of applying an optimal overshoot suppression unit depending on states. The voltage regulator includes: an amplifier for controlling an output transistor based on a voltage obtained by amplifying a difference between a divided voltage and a reference voltage; a first overshoot suppression unit for controlling a gate voltage of the output transistor, to thereby suppress overshoot of the output voltage; a second overshoot suppression unit for controlling an operating current of the amplifier, to thereby suppress the overshoot of the output voltage; and a control circuit. The control circuit is configured to turn on the first overshoot suppression unit immediately after the voltage regulator is powered on, and turn off the first overshoot suppression unit under a state in which the output voltage is stable.

Abstract: Provided is a voltage regulator configured to suppress overshoot and undershoot so as to output a stabilized voltage. The voltage regulator includes: a high pass filter configured to detect a fluctuation in power supply voltage; a high pass filter configured to detect a fluctuation in output voltage; transistors connected in series, which are each configured to cause a current to flow in accordance with an output of corresponding one of the high pass filters; and a clamp circuit configured to clamp a drain voltage of one of the transistors connected in series. The voltage regulator controls a gate voltage of an output transistor based on a drain voltage of a transistor that includes a gate controlled by the drain voltage of the one of the transistors connected in series.

Abstract: Provided is a voltage regulator capable of preventing an output voltage from being increased even when a leakage current flows in an output transistor. The voltage regulator includes a leakage current control circuit. The leakage current control circuit includes an NMOS transistor connected to an output terminal of the voltage regulator. When the output voltage of the voltage regulator increases due to the leakage current of the output transistor, the leakage current control circuit causes the leakage current to flow through the NMOS transistor, to thereby prevent an increase in output voltage.

Abstract: 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.

Abstract: Provided is a semiconductor device including a detection circuit in which, even when a load short-circuit detection circuit and a load open-circuit detection circuit perform false detection due to a fluctuation in power supply voltage and the like, an output of a false detection result can be prevented. The detection circuit includes the load short-circuit detection circuit configured to detect a short circuit of a load, the load open-circuit detection circuit configured to detect an open circuit of the load, and a logic circuit configured to output output signals of the load short-circuit detection circuit and the load open-circuit detection circuit to an output terminal of the logic circuit, in which the logic circuit outputs a signal of a non-detection logic to the output terminal when the outputs of the load open-circuit detection circuit and the load short-circuit detection circuit are detection logics.

Abstract: 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.

Abstract: To provide an overcurrent protection circuit which prevents an excessive current from flowing to an output terminal for a long time, and a semiconductor device and a voltage regulator each equipped with the overcurrent protection circuit. An overcurrent protection circuit is configured to include a first transistor which allows a current proportional to an output current flowing through an output transistor to flow, a constant current circuit which allows a reference current to flow, a comparison circuit which compares the current flowing through the first transistor and the reference current, and a control circuit which controls a gate of the output transistor by a signal outputted from the comparison circuit.

Abstract: An output circuit has a smaller area and restrains outputs from becoming unstable even if a power supply voltage is lower than an operating voltage. A supply terminal of an inverter circuit is provided with switch circuit, and the switch circuit stops the operation of the inverter circuit when the power supply voltage is lower than the operating voltage of the circuit. Further, the output terminal of the inverter circuit is provided with a current source to fix the output to the power supply voltage when the operation of the inverter circuit is stopped.

Abstract: To provide a reference voltage circuit capable of outputting a reference voltage excellent in temperature characteristic. A reference voltage circuit includes a first constant current circuit, a first transistor of a first conductivity type which has a source connected to the first constant current circuit and is operated as a first stage source follower, a second constant current circuit, and a second transistor of a second conductivity type which has a gate connected to the source of the first transistor and a source connected to the second constant current circuit and is operated as a second stage source follower. The reference voltage circuit is configured to output a reference voltage from the source of the second transistor.

Abstract: To provide a voltage regulator capable of preventing a reduction in output voltage and an increase in output noise in a steady state without performing suppression of an overshoot. A voltage regulator is equipped with an overshoot detection circuit which detects an overshoot on the basis of an output voltage, an overshoot suppression circuit which controls an output terminal of an error amplifier circuit, based on the output of the overshoot detection circuit, and a driver state discrimination circuit which discriminates the state of an output transistor, based on an output voltage of the error amplifier circuit. The driver state discrimination circuit is configured to control the operation of the overshoot suppression circuit.

Abstract: A voltage regulator is provided which can suppress an occurrence of overshooting in an output voltage at the time of starting a power source with a source voltage or the like. The voltage regulator includes an error amplifier circuit, an overshooting control circuit that is connected to the gate of an output transistor, and an ON/OFF circuit that controls ON and OFF states of at least the error amplifier circuit. Here, the ON/OFF circuit controls the overshooting control circuit so as to turn on the output transistor when a predetermined time passes after at least the error amplifier circuit is turned on at the time of starting the voltage regulator.

Abstract: Provided is a voltage regulator configured to suppress overshoot and undershoot so as to output a stabilized voltage. The voltage regulator includes: a high pass filter configured to detect a fluctuation in power supply voltage; a high pass filter configured to detect a fluctuation in output voltage; transistors connected in series, which are each configured to cause a current to flow in accordance with an output of corresponding one of the high pass filters; and a clamp circuit configured to clamp a drain voltage of one of the transistors connected in series. The voltage regulator controls a gate voltage of an output transistor based on a drain voltage of a transistor that includes a gate controlled by the drain voltage of the one of the transistors connected in series.

Abstract: Provided is a voltage regulator capable of preventing an output voltage from being increased even when a leakage current flows in an output transistor. The voltage regulator includes a leakage current control circuit. The leakage current control circuit includes an NMOS transistor connected to an output terminal of the voltage regulator. When the output voltage of the voltage regulator increases due to the leakage current of the output transistor, the leakage current control circuit causes the leakage current to flow through the NMOS transistor, to thereby prevent an increase in output voltage.

Abstract: 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.

Abstract: Provided is a power supply switching circuit capable of suppressing a load fluctuation such as undershoot that occurs at an output terminal at the time of power supply switching. The power supply switching circuit includes: a battery connected to the output terminal; a replica current generation circuit for generating a replica current that is proportional to a current flowing from the battery to the output terminal; a voltage regulator connected to the output terminal, the voltage regulator including a reference voltage circuit, an error amplifier circuit, an output transistor, and a voltage divider circuit; and a current mirror circuit for causing the replica current to flow through the output transistor of the voltage regulator.

Abstract: 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.

Abstract: Provided is a voltage regulator having improved overshoot characteristics. In the voltage regulator, a current limiting circuit formed of, for example, a constant current source is provided in series to an output transistor, to thereby limit an output overcurrent. Further, a voltage limiting circuit formed of, for example, a diode is provided to an output terminal, to thereby limit an output voltage.

Abstract: Provided is a battery pack capable of reducing the number of terminals of a battery protection IC. When a battery (15) enters an overdischarge state, a temperature switch IC (12) included in a battery pack (10) monitors a voltage of a voltage monitoring terminal (VM2) provided to an external connection terminal (EB?), rather than a voltage of a terminal of the battery protection IC (11) for use in communication with the temperature switch IC (12), and then shuts down. Therefore, the battery protection IC (11) included in the battery pack (10) does not require an additional terminal for use in communication with the temperature switch IC (12).

Abstract: Provided is a power supply switching circuit capable of suppressing a load fluctuation such as undershoot that occurs at an output terminal at the time of power supply switching. The power supply switching circuit includes: a battery connected to the output terminal; a replica current generation circuit for generating a replica current that is proportional to a current flowing from the battery to the output terminal; a voltage regulator connected to the output terminal, the voltage regulator including a reference voltage circuit, an error amplifier circuit, an output transistor, and a voltage divider circuit; and a current mirror circuit for causing the replica current to flow through the output transistor of the voltage regulator.