To protect a switching element to be used in a boost circuit for an in-cylinder injection type internal combustion engine or the like from damage caused by overheating without using a temperature detection element. In a control circuit that switches a switching element between a conductive state and a non-conductive state, the switching element is controlled or a temperature of the switching element is estimated based on a potential difference between an input terminal and an output terminal of the switching element and a voltage applied to a control terminal of the switching element in the conductive state.

A fuel injection control device includes an electric controller controlling an opening and closing of an injector by energizing a coil in the injector, and a booster circuit boosting a battery voltage to generate a boost voltage. The electric controller includes a valve-opening control unit applying the boost voltage and then applying the battery voltage to the coil to execute a valve-opening control to generate a required valve-opening force, an open valve maintenance control unit applying the battery voltage to the coil to execute an open valve maintenance control to generate an open valve maintenance force and is smaller the required valve-opening force, after the valve-opening control, and a current correction control unit executing a current correction control to correct a maximum value of a current flowing through the coil when the boost voltage is applied in the valve-opening control, according to a decreasing quantity of the battery voltage.

The objective of the present invention is to correct deviation in the injection amount and changes in the injection timing when the voltage of a high-voltage source for a drive device decreases. This drive device for a fuel injection device is equipped with a function whereby, when the pulse width of the injection pulse is set to an energization time 815 that closes a valve after a drive current has been switched to a maintenance current, the injection pulse width when the voltage of a high-voltage source has decreased is corrected so as to be longer than the injection pulse width when the voltage of the high-voltage source has not decreased, and, when the pulse width of the injection pulse is set to an energization time 804 that closes the valve before the drive current has been switched to the maintenance current, the absolute value of the amount of correction of the injection pulse width is made smaller than when the injection pulse width is set to the energization time 815 that closes the valve after the drive current has been switched to the maintenance current.

A fuel injection controller is applied to a fuel injector injecting fuel to be combusted in an internal combustion engine by an open-valve operation of the valve body according to an electromagnetic suction force generated by an energization of a coil. The fuel injection controller controls an injection state of the fuel injector by controlling a coil current flowing through the coil. The fuel injection controller includes an increasing control portion which increases the coil current to a first target value, a holding control portion which holds the coil current increased by the increasing control portion to the first target value, and a changing portion which changes the first target value according to the operation state of the internal combustion engine.

An electromagnetic valve drive device includes: a state detection unit configured to detect an on-state or an off-state of a first switch and a second switch forming a boosting circuit; a boosting control unit configured to control a boosting operation, by performing a synchronous rectification control on switching of the first switch and the second switch, depending on the state of the first switch or the second switch detected by the state detection unit; and a drive circuit configured to drive an electromagnetic valve by supplying a voltage boosted by the boosting operation to the electromagnetic valve.

An injection control unit includes a constant-current control unit executing a constant current control to control a current of a coil to be in a predetermined current range lower than a peak current by allowing or interrupting a first voltage applied to the coil after the peak current starting to open an injector is applied to the coil driving the injector, and a high-voltage applying control unit applying a second voltage higher than the first voltage to the coil in a case where a condition that the current of the coil becomes lower than the predetermined current range is met when the constant-current control unit executes the constant current control.

An injector driving device includes a control circuit of a booster circuit that charges a capacitor by repeatedly switching a booster switch ON/OFF during a voltage boost control to cause a reverse voltage in a coil, and stops the voltage boost control upon determining that a capacitor voltage has reached a corrected target value. The control circuit detects a peak value of the capacitor voltage during an OFF period of the boost switch. The control circuit also detects a capacitor voltage as an ON value during the subsequent ON period of the booster switch. A difference between the peak voltage and the ON value of the capacitor is calculated, and a post-correction target value is set by adding the difference to a reference value of a target value.

A power supply device includes a first power supply circuit, a second power supply circuit, and a power supply-switching unit. The first power supply circuit includes a power storage device having a first capacity and supplies electricity of a first voltage to the electric motor. The second power supply circuit includes a power storage device having a second capacity smaller than the first capacity and supplies electricity of a second voltage higher than the first voltage to the electric motor. The power supply-switching unit supplies electricity from the second power supply circuit to the electric motor at the tune of starting an operation of the electric motor and thereafter supplies electricity from the first power supply circuit to the electric motor.

An injection control device has a current supply controller controlling a supply of an electric current for opening and closing a fuel injection valve, a current monitor monitoring the electric current supplied to the valve, and a boost controller performing a boost voltage generation control that generates a boost voltage from a power supply voltage by a tuning ON/OFF of a switching element for supplying a peak current to open the valve. When the current supply controller supplies the peak current to the fuel injection valve, the boost controller stops the boost voltage generation control in a stop period that includes a timing when an electric current supply amount takes a threshold value of the peak current.

An injection control device opens and closes a fuel injection valve by driving the fuel injection valve with a current to control fuel injection to an internal combustion engine. The injection control device includes: a booster circuit that boosts a battery voltage; a boosting control unit that performs boosting control on the booster circuit; and a charge control setting unit that sets charge permission or charge prohibition for the booster circuit to the boosting control unit.