According to the present invention, by providing control whereby a rising slope or a descending slope of step-up current flowing to a step-up coil is detected, and corrections are made to step-up switching control, the step-up upper and lower limit current values of the step-up circuit can be controlled within intended current threshold values regardless of constant modifications or change in characteristics due to fluctuations of the battery power supply voltage or degradation of step-up circuit elements over time; heat emission by step-up circuit elements can be kept to a minimum; and the step-up recovery time can be adjusted to a constant value regardless of the slope of the step-up current.

An outboard motor includes an electric power source, a mechanical power source auxiliary machine, an electric circuit, an electric supply port, and a switch. The mechanical power source auxiliary machine assists driving a mechanical power source. The electric circuit electrically connects the electric power source and the mechanical power source auxiliary machine. The electric supply port is electrically connected to the electric power source through the electric circuit, and supplies an electric power to an accessory device to be connected thereto. The switch is disposed between the electric power source and the electric supply port in the electric circuit, and is switchable between an on state and an off state. The switch allows a flow of an electric current when switched to the on state, and interrupts the flow of the electric current when switched to the off state.

A method includes receiving a plurality of injection pulses; generating a plurality of drive signals in response to the plurality of injection pulses; generating an interrupt signal in response to the plurality injection pulses, the interrupt signal being one of a high interrupt signal and a low interrupt signal; and transitioning between a plurality of operating states in response to the interrupt signal.

A method for checking the function of a sensor for detecting soot is provided, the sensor including at least two measuring electrodes situated on a substrate made of an electrically insulating material, and a heating element, the method including: carrying out a first current-voltage measurement at a first temperature to ascertain a first measured variable, carrying out a second current-voltage measurement at a second temperature to ascertain a second measured variable, and forming a difference between the first measured variable and the second measured variable.

A load driving device including a converter, an output circuit and a timer circuit is provided. The converter receives a communication frame including a data signal through a serial communication and performs parallel conversion on the data signal to output an instruction signal instructing the output circuit to transition to a first state when the data signal includes first serial data and output an instruction signal instructing the output circuit to transition to a second state when the data signal includes second serial data. A timer circuit measures a duration time during which the converter receives the first serial data. When the measuring duration time arrives at an abnormality determination time, the timer circuit forces the output circuit to transition to the second state when the measuring duration time arrives at an abnormality determination time.

A booster circuit installed in a fuel injection device of an internal combustion engine, wherein malfunctions and characteristic changes of the booster circuit are detected, among which the detection distinguishes between decreases in capacity caused by deterioration or broken wires in a booster capacitor, and failures of a current monitor circuit, coil, externally connected fuel injection valve, and other components. The range of decrease in boost voltage when the fuel injection valve is opened is monitored, as is the range of increase per switch performed in order to restore the boost voltage. This makes it possible to detect malfunctions and characteristic changes of the booster circuit.