Abstract: A motor drive device includes a storage unit that stores an initial value of a static capacitance correlation value of a static capacitance of a smoothing capacitor in an initial state, when the smoothing capacitor is connected to an inverter. A measurement unit of the motor drive device includes a timing generation circuit and a calculation unit. The measurement unit measures the static capacitance correlation value of the smoothing capacitor as a measured value at a time after the initial state. A determination unit of the motor drive device determines whether there is deterioration in the smoothing capacitor based on a relationship between the measured value and the initial value. A restrictor of the motor drive device restricts a maximum rotation number of a motor when capacitor deterioration is determined, thereby reducing a ripple current, limiting heat generation in the capacitor, and extending the product life of the capacitor, without increasing the number of parts in the motor drive device.

Abstract: A power conversion circuit is provided. The power conversion circuit includes a bridge circuit connected between power input terminals, a drive circuit supplied with power from a DC power source via the power input terminals, a boost circuit for, when the DC power source is reversely connected, starting up and supplying power to a control circuit, and a reverse voltage detection circuit for detecting a reverse voltage generated when the DC power source is reversely connected.

Abstract: A power conversion circuit is provided. The power conversion circuit includes a bridge circuit connected between power input terminals, a drive circuit supplied with power from a DC power source via the power input terminals, a boost circuit for, when the DC power source is reversely connected, starting up and supplying power to a control circuit, and a reverse voltage detection circuit for detecting a reverse voltage generated when the DC power source is reversely connected.

Abstract: A motor drive device includes a storage unit that stores an initial value of a static capacitance correlation value of a static capacitance of a smoothing capacitor in an initial state, when the smoothing capacitor is connected to an inverter. A measurement unit of the motor drive device includes a timing generation circuit and a calculation unit. The measurement unit measures the static capacitance correlation value of the smoothing capacitor as a measured value at a time after the initial state. A determination unit of the motor drive device determines whether there is deterioration in the smoothing capacitor based on a relationship between the measured value and the initial value. A restrictor of the motor drive device restricts a maximum rotation number of a motor when capacitor deterioration is determined, thereby reducing a ripple current, limiting heat generation in the capacitor, and extending the product life of the capacitor, without increasing the number of parts in the motor drive device.

Abstract: A motor driver drives a motor by receiving a power supply from a direct current power source, and includes a half-bridge circuit, a smoothing capacitor, a power supply circuit, a current adjuster circuit, and a control circuit. The half-bridge circuit and the smoothing capacitor are connected at positions between a power supply line and a ground line. The current adjuster circuit adjusts a current supply amount to the power supply circuit. The control circuit controls the half-bridge circuit and the current adjuster circuit. The control circuit controls the current adjuster circuit based on an operating state of the half-bridge circuit.

Abstract: A power device includes a semiconductor relay and a pre-charger that has a reference voltage generator and a controller. The semiconductor relay is disposed at a position between a battery supplying electric power to a power converter that serves as a load and a smoothing capacitor connected on a battery side of the power converter in parallel with the power converter. The reference voltage generator generates a reference voltage having a gradually-increasing voltage value in a pre-charge period, prior to a turning ON of the semiconductor relay accompanying a turning ON of an ignition switch. The controller controls the semiconductor relay such that a charge voltage which is an inter-terminal voltage of the smoothing capacitor is set to a preset value according to the reference voltage.

Abstract: A power device includes a semiconductor relay and a pre-charger that has a reference voltage generator and a controller. The semiconductor relay is disposed at a position between a battery supplying electric power to a power converter that serves as a load and a smoothing capacitor connected on a battery side of the power converter in parallel with the power converter. The reference voltage generator generates a reference voltage having a gradually-increasing voltage value in a pre-charge period, prior to a turning ON of the semiconductor relay accompanying a turning ON of an ignition switch. The controller controls the semiconductor relay such that a charge voltage which is an inter-terminal voltage of the smoothing capacitor is set to a preset value according to the reference voltage.

Abstract: An inverter main circuit using high-side MOSFETS converts a power source voltage of a battery to an alternating current, and supplies the alternating current to a three-phase motor. A control circuit drives, via a high-side drive circuit and a low-side drive circuit, the MOSFETS. A charge pump circuit boosts the power source voltage to a charge pump voltage. A bootstrap circuit outputs a bootstrap voltage that is boosted by diodes and capacitors, which is then passed to a clamp circuit for clamping and outputting as a clamp voltage. Based on the supply of the charge pump voltage or the clamp voltage in response to a fluctuation of the power source voltage, a continuous circuit operation is provided while protecting the circuit in operation.

Abstract: An inverter main circuit using high-side MOSFETS converts a power source voltage of a battery to an alternating current, and supplies the alternating current to a three-phase motor. A control circuit drives, via a high-side drive circuit and a low-side drive circuit, the MOSFETS. A charge pump circuit boosts the power source voltage to a charge pump voltage. A bootstrap circuit outputs a bootstrap voltage that is boosted by diodes and capacitors, which is then passed to a clamp circuit for clamping and outputting as a clamp voltage. Based on the supply of the charge pump voltage or the clamp voltage in response to a fluctuation of the power source voltage, a continuous circuit operation is provided while protecting the circuit in operation.

Abstract: In a power conversion system, when a frequency of a ripple current, flowing into a power supply line of a direct current power source, is equal to a resonance frequency of an LC filter, a resonance is efficiently restricted. In the LC filter connected between the direct current power source and an inverter circuit, an N channel MOSFET is arranged between a capacitor and ground. When a BPF detects an occurrence of the resonance in the LC filter, an inverting amplifier operates the N channel MOSFET and changes a series resistance value of a current path on which the capacitor is arranged.

Abstract: In a power conversion system, when a frequency of a ripple current, flowing into a power supply line of a direct current power source, is equal to a resonance frequency of an LC filter, a resonance is efficiently restricted. In the LC filter connected between the direct current power source and an inverter circuit, an N channel MOSFET is arranged between a capacitor and ground. When a BPF detects an occurrence of the resonance in the LC filter, an inverting amplifier operates the N channel MOSFET and changes a series resistance value of a current path on which the capacitor is arranged.

Abstract: A constant current-constant voltage circuit includes a first resistor; a first transistor that is an N-channel type; a second transistor; a third transistor that is a P-channel type; a fourth transistor that is a P-channel type; a fifth transistor; a second resistor; and a first constant voltage element. The second resistor is coupled between the intermediate node and a source of the third transistor and the first constant voltage element is coupled between a source of the second transistor and the second power source line. A bias is set up and a source potential of the first transistor is equal to a source potential of the fifth transistor.

Abstract: Provided is a voltage regulator capable of accurately adjusting a tail current of a differential amplifier circuit without adding a test terminal. The voltage regulator includes: a constant current circuit for causing the tail current of the differential amplifier circuit to flow; a protection circuit; a current output circuit for outputting a current of the constant current circuit to a test terminal for measuring characteristics of the protection circuit; a switch circuit for stopping a function of the protection circuit; and a fuse provided between the test terminal and the current output circuit.

Abstract: Provided is a voltage regulator including an overcurrent protection circuit, which does not need a test circuit. The voltage regulator has a configuration in which a reference voltage circuit includes an element that determines a reference voltage and an overcurrent protection circuit includes an element that determines a maximum output current, the element of the reference voltage circuit and the element of the overcurrent protection circuit having the same characteristics. Accordingly, there is a correlation between an output voltage before trimming and the maximum output current for overcurrent protection. Thus, a maximum output current before trimming can be estimated without performing evaluation by a test circuit.

Abstract: Provided is a voltage regulator having improved transient response characteristics even when a load current is switched from a light load to a heavy load. The voltage regulator includes, to a gate of a detection transistor constituting an output current detection circuit: a resistive element for interrupting the gate of the detection transistor from an output terminal of a differential amplifier circuit in an AC manner; and a capacitive element connected to an output terminal of the voltage regulator in an AC manner.

Abstract: Provided is a voltage regulator capable of accurately adjusting a tail current of a differential amplifier circuit without adding a test terminal. The voltage regulator includes: a constant current circuit for causing the tail current of the differential amplifier circuit to flow; a protection circuit; a current output circuit for outputting a current of the constant current circuit to a test terminal for measuring characteristics of the protection circuit; a switch circuit for stopping a function of the protection circuit; and a fuse provided between the test terminal and the current output circuit.

Abstract: Provided is a voltage regulator including a soft-start circuit having a small area and capable of suppressing an inrush current by causing a reference voltage circuit to rise gently with time. In the soft-start circuit, a capacitor is connected to an output of a reference voltage circuit driven by a constant current of a constant current circuit, and hence the soft-start circuit can raise a reference voltage gently to prevent an inrush current with a small area. After the end of a soft-start period, the constant current circuit is disconnected, and the reference voltage circuit is driven by a power source. Thus, the operation becomes stable.

Abstract: In a power supply circuit, an error amplifier controls a main transistor based on a detection voltage according to an output voltage and a reference voltage corresponding to a target voltage of the output voltage such that the output voltage coincides with the target value. A phase compensation circuit for the power supply circuit includes a level shift circuit and a phase compensation capacitor. The level shift circuit generates a shift voltage by shifting a dc component of the output voltage toward a ground potential by a predetermined voltage, and outputs the shift voltage from an output terminal of the level shift circuit. The phase compensation capacitor is disposed on a route between the output terminal of the level shift circuit and an input terminal of an amplifier circuit of the error amplifier.

Abstract: Provided is a voltage regulator capable of reducing an influence of an offset to obtain an accurate output voltage. The voltage regulator includes: a first stage amplifier for amplifying and outputting a difference between a reference voltage and a divided voltage obtained by dividing a voltage output by an output transistor, to thereby control a gate of the output transistor; and a cascode amplifier circuit, in which the first stage amplifier includes: a first high breakdown voltage NMOS transistor as an input transistor; and an NMOS transistor as a tail current source, and in which the cascode amplifier circuit includes a second high breakdown voltage NMOS transistor as a cascode transistor.

Abstract: Provided is a voltage regulator having improved transient response characteristics even when a load current is switched from a light load to a heavy load. The voltage regulator includes, to a gate of a detection transistor constituting an output current detection circuit: a resistive element for interrupting the gate of the detection transistor from an output terminal of a differential amplifier circuit in an AC manner; and a capacitive element connected to an output terminal of the voltage regulator in an AC manner.