Abstract: A communication apparatus in an airbag system includes an airbag ECU as a master unit, sets of communication lines and slave sensor devices. The slave sensor devices are respectively connected to the airbag ECU through the set of communication lines. The airbag ECU transmits data transmission request commands to the respective sets of communication lines at timings which are different from each other. Thus, transmission timings in the respective sets of communication lines are prevented from being synchronized, and noise which develops in consequence of the data communications between the master unit and the slave sensor devices can be reduced.

Abstract: A communication apparatus in an airbag system includes an airbag ECU as a master unit, sets of communication lines and slave sensor devices. The slave sensor devices are respectively connected to the airbag ECU through the set of communication lines. The airbag ECU transmits data transmission request commands to the respective sets of communication lines at timings which are different from each other. Thus, transmission timings in the respective sets of communication lines are prevented from being synchronized, and noise which develops in consequence of the data communications between the master unit and the slave sensor devices can be reduced.

Abstract: In a voltage booster circuit, a switching transistor turns on and off a flow of an electric current in a booster coil thereby to boost a voltage supplied form a d.c. power source. A back-up circuit is connected to the booster coil to store the boosted voltage as an output voltage. A current detection circuit detects an electric current flowing in the switching transistor and turns off the switching transistor, when the detected current reaches a predetermined level. An off-period control circuit variably controls an off-period of the switching transistor after the switching transistor is turned off. The off-period control circuit varies the off-period in accordance with a voltage difference between the output voltage and an upper limit threshold voltage.

Abstract: In a voltage booster circuit, a switching transistor turns on and off a flow of an electric current in a booster coil thereby to boost a voltage supplied form a d.c. power source. A back-up circuit is connected to the booster coil to store the boosted voltage as an output voltage. A current detection circuit detects an electric current flowing in the switching transistor and turns off the switching transistor, when the detected current reaches a predetermined level. An off-period control circuit variably controls an off-period of the switching transistor after the switching transistor is turned off. The off-period control circuit varies the off-period in accordance with a voltage difference between the output voltage and an upper limit threshold voltage.

Abstract: An automotive occupant restraint system with a simple and compact energy reserve circuit is provided which includes an occupant restraint mechanism, a step-up circuit, a backup capacitor, a crash monitor, a firing circuit, and a switching circuit. The step-up circuit steps up the voltage supplied from a battery to charge the backup capacitor up to a given voltage level. The crash monitor monitors a vehicle crash to provide a crash signal. The firing circuit is responsive to the crash signal to activate the occupant restraint mechanism. The switching circuit selects between a first and a second power supply mode.

Abstract: A drive circuit for a vehicle occupant safety apparatus includes a device for activating the vehicle occupant safety apparatus. A first transistor is connected in series with the device. A constant-current circuit receives electric energy from a power supply, and feeds a constant current to the device when the first transistor falls into its on state. The constant-current circuit includes a second transistor connected in series with the device. The second transistor includes an N-channel field-effect transistor. A third transistor is connected to the second transistor. The second and third transistors form a current mirror circuit. The third transistor includes an N-channel field-effect transistor. A voltage between a gate and a source of the third transistor is regulated at a constant level. Gate voltages of the second and third transistors are controlled in response to source voltages of the second and third transistors to equalize the source voltages of the second and third transistors.

Abstract: An occupant protection system for an automotive vehicle is provided which includes a pair of squibs for activating a pair of occupant protection units such as an airbag unit and a pretensioner for a seat belt, a backup capacitor, and a switching circuit. The switching circuit serves to allow the electric power stored in the backup capacitor to be supplied to at least one of the occupant protection units upon occurrence of a collision of the vehicle with another object when a sufficient power is not supplied from the power source to the squibs or when a line connected to the power source is broken by the collision of the vehicle.

Abstract: A battery condition detecting apparatus includes a current detecting apparatus, a voltage detector and a current accumulator of a battery. The battery condition detecting apparatus detects a first battery capacity when an engine is started based on the battery voltage and battery current when the starter is started; determines an initial capacity of the battery based on the first battery capacity; adds to this initial capacity, a battery current accumulated value which has been accumulated by the battery current accumulator after determining the first battery capacity, whereby a second battery capacity is detected after the engine has been started; and further comparing the presently detected first battery capacity with the second battery capacity just before this first battery capacity is detected, thereby setting the smaller capacity as the initial value.

Abstract: A battery condition detecting apparatus includes a current detecting apparatus, a voltage detector and a current accumulator of a battery. The battery condition detecting apparatus detects a first battery capacity when an engine is started based on the battery voltage and battery current when the starter is started; determines an initial capacity of the battery based on the first battery capacity; adds to this initial capacity, a battery current accumulated value which has been accumulated by the battery current accumulator after determining the first battery capacity, whereby a second battery capacity is detected after the engine has been started; and further comparing the presently detected first battery capacity with the second battery capacity just before this first battery capacity is detected, thereby setting the smaller capacity as the initial value.

Abstract: A battery charging control apparatus for a vehicle generator comprises switching means for controlling a field current flowing through a field winding of the generator intermittently, voltage control means for controlling the switching means to increase the field current gradually in order to maintain a voltage of a battery to be charged at a first predetermined value when the battery voltage drops below the first predetermined value, generator output voltage detecting means for detecting an output voltage of the generator, charging abnormality warning means, which detects occurrence of charging abnormality, when the detected generator output voltage drops to assume a second predetermined value and below, which value is lower than the first predetermined value, and at the same time the battery voltage remains at the first predetermined value and below for a predetermined time, and which then turns on a charging abnormality warning lamp, and current increasing means which increases the field current to thereby

Abstract: A battery voltage regulator for a vehicle charging system includes a voltage control circuit for controlling a battery terminal voltage and an external terminal connected to the positive terminal of a battery through the series combination of a charge lamp and an ignition switch. The regulator is at least composed of a charge lamp drive circuit responsive to a generation output of an alternator in order to energize the charge lamp, a power supply circuit responsive to the potential at the above mentioned external terminal to supply operational power to the voltage control circuit, and a malfunction-preventing circuit connected between the above mentioned external terminal and ground. The malfunction-preventing circuit prevents the power supply circuit from operating by disturbances such as leakage current flowing into the regulator through the external terminal.

Abstract: The battery voltage regulating system for vehicle use of this invention controls the energization of an alternating-current generator by a generation control circuit responsive to a battery voltage in normal operation. However, if a fault condition such as the damage of a resistor of the generation control circuit or a break in the warning line occurs, and even if the resulting warning is ignored or over-looked by the driver, a warning control circuit provided a requisite control to regulate the generator's generation while giving a warning. In this manner, an average voltage of a battery is kept substantially equal to a predetermined constant value controlled by said generation control circuit even if such unexpected situation occurs. Thus, the battery voltage regulating system can prevent the battery from being excessively charged.

Abstract: A voltage regulating system for an automotive vehicle having a switching transistor connected to a field winding of an alternating current generator and a regulator for comparing a battery voltage with a reference value and for driving the transistor into a conductive state when the battery voltage is lower than the reference value. A current limiting circuit is provided for limiting the field current when the switching transistor is going to be driven into the conductive state over a predetermined interval, so that a maximum charging current can be obtained and an unfavorable heating of the switching transistor can be avoided.

Abstract: A battery voltage regulating system for an automotive vehicle, wherein a field current flowing through a field coil of an alternator is periodically cut off irrespectively of whether a battery voltage is higher or lower than a reference voltage, and a conduction ratio of the field current is controlled in accordance with a difference between the battery voltage and the reference voltage. The reference voltage is changed in response to an increase or decrease of the conduction ratio, so that a battery voltage is prevented from decreasing when the conduction ratio is increased.

Abstract: A battery charging control system for automobile, wherein a voltage regulator for regulating the output voltage of an AC generator for charging the automobile battery is controlled by detecting changes of the output voltage. When the output voltage of the generator changing with ripples is reduced with an increase of load current, the minimum value of the output voltage is detected, while when the output voltage increases with an increase of the generator rotational speed, an average value of the output voltage is detected. In accordance with these values, the voltage regulator is controlled to compensate for the changes of the output voltage of the generator.