Ablic Inc.

Seiko Instruments Inc

Sii Semiconductor Corporation

Kaoru Sakaguchi

Yasuhiko Ogura

Teruo Suzuki

Takashi Imura

Kazuhiro Tsumura

Noriyuki Harada

Munetaka Yoshimura

Hiroki Takahashi

To provide a resistance device which has a small temperature dependence, in which a resistance value is adjustable in a wide range of from a high resistance value to a low resistance value, and which has a small circuit area, and to provide a current detection circuit including the resistance device. The resistance device is to be connected between two terminals, and a resistance value thereof is variable, the resistance device including: a reference resistor; a series variable resistor circuitry including at least one parallel variable resistor circuit which is connected in series to each other, and which each includes a resistor and a trimming element connected in parallel to the resistor; and a parallel variable resistor circuitry including at least one series variable resistor circuit which is connected in parallel to each other, and which each includes a resistor and a trimming element connected in series to the resistor.

Resistance device and current detection circuit including the resistance device

An overcurrent protection circuit configured to limit an output current flowing through an output transistor includes a sense transistor that provides a sense current proportional to the output current, a sense resistor through which the sense current flows, a current limiting circuit that detects a sense voltage generated by the sense resistor and controls a gate voltage of the output transistor, and a current correction circuit that provides the sense resistor with a corrected sense current added to the sense current based on a difference of voltage between a drain voltage of the output transistor and a drain voltage of the sense transistor.

Overcurrent protection circuit and load driving device

An overheat protection circuit includes a first constant current source which supplies a first constant current to a temperature sensitive element, a first transistor provided between the temperature sensitive element and the first constant current source, an output current detection circuit which controls a gate voltage of the first transistor by a voltage based on a sense current corresponding to an output current of a semiconductor device, and an output circuit which supplies an overheat detection signal based on a result of comparison between a temperature sensitive current and the first constant current.

Overheat protection circuit and semiconductor device including the same

A voltage regulator includes an error amplifier which controls the gate of an output transistor so that a feedback voltage based on an output voltage of an output terminal matches a first reference voltage, a first transistor having a gate to which a second reference voltage is supplied, and a first resistor connected between the gate of the output transistor and the source of the first transistor. The first resistor functions as a resistance constituting a phase compensation circuit by a current flowing therethrough in response to a small output current of the output transistor.

Voltage regulator having a phase compensation circuit

A voltage regulator includes an output voltage terminal which supplies an output voltage having a preset value, a voltage adjustment terminal which detects the output voltage, an error amplifier which compares the output voltage and a reference voltage to control the output voltage, a phase compensation capacitor, a test circuit which switches a normal mode with a test mode to test the phase compensation capacitor, a switch which makes the phase compensation capacitor valid or invalid, and a constant current source which makes a bias current of the error amplifier in the test mode lower than that in the normal mode.

Voltage regulator and method of testing the same

A voltage regulator includes an error amplifier which receives a feedback voltage and a reference voltage, an amplifier circuit which receives an output voltage of the error amplifier and controls a gate of an output transistor by a first output voltage, and a non-regulation detection circuit which detects a non-regulation state of the voltage regulator based on a second output voltage of the amplifier circuit. The amplifier circuit includes a first transistor receiving the output voltage of the error amplifier at a gate of the first transistor, and a second transistor connected to a drain of the first transistor, and provides the second output voltage based on a gate-source voltage of the second transistor.

Voltage regulator

A reference voltage circuit includes a first MOS transistor pair having a first MOS transistor of an enhancement type having a gate and a drain connected to each other, and a second MOS transistor of a depletion type having a gate connected to a source of the first MOS transistor, a source connected to the drain of the first MOS transistor, and a drain connected to an output terminal; and a second MOS transistor pair having a third MOS transistor of an enhancement type having a gate and a drain connected to the output terminal and a source connected to the source of the second MOS transistor, and a fourth MOS transistor of a depletion type having a gate connected to the source of the third MOS transistor and a source connected to the output terminal. All the MOS transistors operate in a weak inversion region.

Reference voltage circuit and semiconductor device

A constant current circuit includes a first current mirror circuit connected to a first power supply and having a first input transistor and a first output transistor of a first conductivity type, a second current mirror circuit having a second output transistor of a second conductivity type provided between the first input transistor and a second power supply, and a second input transistor of the second conductivity type provided between the first output transistor and the second power supply, a resistor interposed between the second output transistor and the second power supply, and a capacitor having one end connected to the first power supply and the other end connected to a connecting point of the second output transistor and the resistor.

Constant current circuit for suppressing transient variation in constant current

A comparator includes a first constant current source, a first transistor having a drain connected to the first constant current source, a gate connected to a non-inverted input terminal, and a source connected to an inverted input terminal, a second constant current source connected between the inverted input terminal and a second power supply terminal, a second transistor having a source connected to a first power supply terminal, a gate connected to the drain of the first transistor, and a drain connected to an output terminal, and a third constant current source connected between the drain of the second transistor and the second power supply terminal. An oscillation circuit includes comparators in which at least one of the comparators is a comparator described above.

Comparator and oscillation circuit

Provided is a monitoring circuit for a system including an LDO regulator. The monitoring circuit includes: a non-saturation detection circuit configured to detect a non-saturation state of an output transistor of the LDO regulator configured to supply a power supply voltage to an MPU; a current detection circuit configured to detect that an output current from the output transistor is equal to or more than a predetermined current value; and a watchdog timer configured to monitor operation of the MPU. The watchdog timer is enabled when the output transistor is not in a non-saturation state and an output current from the output transistor is equal to or more than a predetermined current value.

Monitoring circuit and semiconductor device

Provided is a monitoring circuit equipped with a first abnormality detection circuit which detects a first abnormal state of a semiconductor device under surveillance, a second abnormality detection circuit which detects a second abnormal state of the semiconductor device under surveillance, a reset circuit which outputs a reset signal based on a logical sum of a first abnormality detection signal output from the first abnormality detection circuit and a second abnormality detection signal output from the second abnormality detection circuit to a first output terminal, and an output holding circuit which stores which of the first abnormality detection signal and the second abnormality detection signal is supplied, and outputs an abnormality discrimination signal corresponding thereto to a second output terminal.

Monitoring circuit

A voltage regulator includes an error amplifier which receives a feedback voltage and a reference voltage and thereby controls a gate voltage of an output transistor, a non-regulation detection circuit having a differential amplifier circuit operating on a current corresponding to an output current of the output transistor, and an overshoot suppression circuit having an overshoot detection circuit which enables an overshoot detection by a signal indicating the detection of non-regulation state from the non-regulation detection circuit.

There is provided an overcurrent protection circuit having a sense transistor through which a first sense current proportional to an output current of an output transistor flows, a voltage-current converting circuit connected between an input terminal of the output transistor and an output terminal thereof, and configured to output a first current, a first current-voltage converting circuit configured to output a first voltage proportional to the first current, a voltage detection circuit configured to detect the first voltage and to output a second sense current based on the output current of the output transistor, a second current-voltage converting circuit through which the first sense current and the second sense current flow, and a current limiting circuit configured to limit the output current of the output transistor based on a second voltage supplied from the second current-voltage converting circuit.

Overcurrent protection circuit and voltage regulator

A voltage regulator includes an error amplifier, and the error amplifier includes a differential pair constituted by a pair of transistors, a current adjustment circuit that provides a bias current proportional to an output current supplied from an output transistor to the differential pair, a source output circuit and a sink output circuit that provide a current based on a current flowing through the differential pair to an output terminal of the error amplifier, and a phase compensation circuit that controls a current of the sink output circuit based on a current of the current adjustment circuit.

Between a power supply potential and a reference potential, a first PMOS transistor and a first NMOS transistor are connected in series via an inverting output node and a second PMOS transistor and a second NMOS transistor are connected in series via a non-inverting output node. A third NMOS transistor is connected in parallel to the first NMOS transistor and a fourth NMOS transistor is connected in parallel to the second NMOS transistor. A gate of the first PMOS transistor and a gate of the third NMOS transistor are connected to the non-inverting output node and a gate of the second PMOS transistor and a gate of the fourth NMOS transistor are connected to the inverting output node. The first and second NMOS transistors receive a non-inverted signal and an inverted signal of an input signal at their gates, respectively.

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Chiba, Japan

Kaoru Sakaguchi