Abstract: A vehicular generator unit includes an alternator and a generator control system that controls the alternator. The alternator is driven by an engine to achieve the power generation for charging a battery. The generator control system includes a transistor for intermitting a field current therethrough so as to control the power generation of the alternator. The system further includes a switching circuit which suppresses the duty of the transistor to a low value, where the alternator can not perform the power generation for the battery, until complete engine start-up or self-rotation is detected. On the other hand, when start-up is detected, the duty of the transistor is switched to a value where the alternator can perform the power generation for the battery. The duty of the transistor is then increased gradually to 100%.

Abstract: Voltage of a terminal at a high impedance is set to a fixed voltage (2.5 V) by a constant current source and a resistor, and whether the voltage of the terminal is a fixed voltage which is between 3.5 V and 5.5 V or not is detected by comparators and a NOR circuit. A control signal is sent from an ECU to the terminal to turn on a switching transistor to lower a divided voltage so that the alternator generates a high voltage only when the voltage of the terminal is the special voltage, and generates normal voltage otherwise. In case of disconnection of the communication line or grounding of the communication line, or when the battery voltage is applied to the communication line, the voltage of the terminal does not become abnormal voltage but become the normal voltage. Thus, abnormal voltage may not applied to the battery.

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: The output of a voltage controlled oscillator serving as a local oscillator is frequency divided by a prescaler and a programmable frequency divider, and the frequency divided output is applied to a phase locked loop including a phase comparator and a charge pump. An S curve signal obtained from a frequency discriminator is applied to an automatic frequency control loop including a window comparator and a charge pump. The outputs of these two charge pumps are applied through an analog switch to a common low-pass filter and the output of the low-pass filter is applied to the voltage controlled oscillator as a control voltage. A state of reception by the tuner is detected based on the output of an intermediate frequency amplifier and the analog switch is responsive to the detected output and a lock detected output of the phase locked loop.