An electronic device includes a first substrate, a wiring substrate (second substrate) disposed over the first substrate, and an enclosure (case) in which the first substrate and the wiring substrate are accommodated and that has a first side and a second side. A driver component (semiconductor component) is mounted on the wiring substrate. A gate electrode of a first semiconductor component is electrically connected to the driver component via a lead disposed on a side of the first side and a wiring disposed between the driver component and the first side. A gate electrode of a second semiconductor component is electrically connected to the driver component via a lead disposed on a side of the second side and a wiring disposed between the driver component and the second side.

A switching circuit includes: a drive power supply; a first transistor and a second transistor; a drive signal source; and a drive circuit. Each of the first transistor and the second transistor includes: a drain electrode and a source electrode in which a main current flows when a corresponding one of the first transistor and the second transistor is ON; a first source terminal for passing the main current; and a second source terminal. Here, the first source terminal is connected to the source electrode at an impedance lower than an impedance of the second source terminal.

An operation coil drive device includes a drive control unit to perform control to set, for a semiconductor switching element to switch on and off the source voltage applied to an operation coil of a magnetic contactor, a larger ON/OFF time ratio for a circuit-closing control and a smaller ON/OFF time ratio for a holding control, wherein the drive control unit includes: a circuit-closing-control inductance calculation unit to calculate an inductance of the operation coil immediately after a start of the circuit-closing control; a circuit-closing-control resistance value calculation unit to calculate a direct current resistance value of the operation coil based on the calculation result; and a circuit-closing-control switching correction unit to correct the ON/OFF time ratio of the semiconductor switching element for the circuit-closing control based on the calculation result.

An operation coil drive device includes a drive control unit to perform control to set, for a semiconductor switching element to switch on and off the source voltage applied to an operation coil of a magnetic contactor, a larger ON/OFF time ratio for a circuit-closing control and a smaller ON/OFF time ratio for a holding control, wherein the drive control unit includes: a circuit-closing-control inductance calculation unit to calculate an inductance of the operation coil immediately after a start of the circuit-closing control; a circuit-closing-control resistance value calculation unit to calculate a direct current resistance value of the operation coil based on the calculation result; and a circuit-closing-control switching correction unit to correct the ON/OFF time ratio of the semiconductor switching element for the circuit-closing control based on the calculation result.

Disclosed herein are an apparatus and method of measuring a coil current of a hydraulic valve. The apparatus includes a first coil current measurement unit configured to receive a first coil current control signal from a coil current control device during an ON operating section of the hydraulic valve in operating sections of the hydraulic valve operated by receiving power of a battery, and measure a first coil current value flowing through a coil of the hydraulic valve using a first switching element to be switched ON, and a second coil current measurement unit configured to receive a second coil current control signal from the coil current control device during an OFF operating section of the hydraulic valve in the operating sections of the hydraulic valve operated by receiving power of the battery, and measure a second coil current value flowing through the coil of the hydraulic valve using a second switching element to be switched ON.

Disclosed herein are an apparatus and method of measuring a coil current of a hydraulic valve. The apparatus includes a first coil current measurement unit configured to receive a first coil current control signal from a coil current control device during an ON operating section of the hydraulic valve in operating sections of the hydraulic valve operated by receiving power of a battery, and measure a first coil current value flowing through a coil of the hydraulic valve using a first switching element to be switched ON, and a second coil current measurement unit configured to receive a second coil current control signal from the coil current control device during an OFF operating section of the hydraulic valve in the operating sections of the hydraulic valve operated by receiving power of the battery, and measure a second coil current value flowing through the coil of the hydraulic valve using a second switching element to be switched ON.

A circuit includes first and second half bridges, a first inductor, a second inductor, and a main inductor. The half bridges each include a high side switch, a low side switch, and a gate driver configured to apply switching signals to the high side switch and the low side switch. The first inductor has one side electrically connected to an output node of the first half bridge between the high side switch and the low side switch. The second inductor has one side electrically connected to an output node of the second half bridge between the high side switch and the low side switch. The main inductor is coupled to a node between the other sides of the first and second inductors. The main inductor has a greater inductance than each of the first and second inductors, and the first and second inductors are inversely coupled to one another.

An electromagnetic actuation system includes an actuator having an electrical coil, a magnetic core, and an armature. The system further includes a controllable drive circuit for selectively driving current through the electrical coil. A control module provides an actuator command to the drive circuit effective to drive current through the electrical coil to actuate the armature. The control module includes a magnetic force control module configured to adapt the actuator command to converge magnetic force within the actuator to a preferred force level.

An electromagnetic actuation system includes an actuator having an electrical coil, a magnetic core, and an armature. The system further includes a controllable drive circuit for selectively driving current through the electrical coil. A control module provides an actuator command to the drive circuit effective to drive current through the electrical coil to actuate the armature. The control module includes a magnetic force control module configured to adapt the actuator command to converge magnetic force within the actuator to a preferred force level.

An electromagnetic actuation system includes an actuator having an electrical coil, a magnetic core, and an armature. The system further includes a controllable bi-directional drive circuit for selectively driving current through the electrical coil in either of two directions. The control module provides an actuator command to the drive circuit effective to drive current through the electrical coil in a first direction to actuate the armature and in a second direction subsequent to armature actuation to oppose residual flux within the actuator. The control module includes a feed forward control module configured to adapt the actuator command to converge residual flux within the actuator to a preferred flux level.