Abstract: When a microcomputer is automatically reset due to uncontrollable process and recovers from reset, a cancel pulse signal is outputted from the microcomputer to a hold circuit to stop supply of a driving current to a relay. This pulse is generated, when a predetermined condition indicative of possibility of battery rundown lasts for a predetermined time. The predetermined condition includes that a hold set condition is detected based on a status signal inputted from the hold circuit; a card key is present in a key slot; a key verification inputted from an immobilizer ECU is not available; a vehicle speed is zero; and an engine revolution is zero.

Abstract: A sampling voltage is periodically applied between contacts of a switch of a device to determine a status of the switch. When a CPU is in a sleep state and the status of the switch is determined closed, the CPU is activated. The sampling voltage when the CPU is in the sleep state is adjusted lower than the one when the CPU is in the wakeup state. This reduces power consumption for the switch status determination. The sampling voltage adjusted at the lower level periodically adjusted to a higher level to reduce errors in the determination due to insulation films on the contacts.

Abstract: A load operating means controls electricity supplied from a power source to a starter in an auxiliary system for starting an engine. An engine control means and an auxiliary electricity supply means turn the load operating means ON for supplying electricity from the power source to the starter in accordance with electricity supply from a power supply device when the engine is started. When voltage of the power supply device becomes less than a reset level, the engine control means resets electricity supply to the load operating means. When the engine control means starts the engine, the auxiliary electricity supply means supplies electricity to the load operating means at a timing simultaneously with or in advance of supplying electricity by the engine control means. When the engine control means resets the electricity supply, the auxiliary electricity supply means supplies electricity instead of the engine control means.

Abstract: A power control circuit is provided in a vehicle control ECU mounted in a vehicle. The control circuit, when making a shift to a test mode by a test mode circuit, closes a relay to supply a power voltage from a battery to a power line in the similar manner as an ignition main switch is turned on. A logic circuit section of the test mode circuit is reset by an OR logic of a set level of a test terminal and a level of the power line.

Abstract: A load operating means controls electricity supplied from a power source to a starter in an auxiliary system for starting an engine. An engine control means and an auxiliary electricity supply means turn the load operating means ON for supplying electricity from the power source to the starter in accordance with electricity supply from a power supply device when the engine is started. When voltage of the power supply device becomes less than a reset level, the engine control means resets electricity supply to the load operating means. When the engine control means starts the engine, the auxiliary electricity supply means supplies electricity to the load operating means at a timing simultaneously with or in advance of supplying electricity by the engine control means. When the engine control means resets the electricity supply, the auxiliary electricity supply means supplies electricity instead of the engine control means.

Abstract: An engine starting assist system includes an auxiliary ECU having a voltage booster, an engine ECU, a starter relay, and a starter that allows the engine to be started when a current flows through the starter relay. The auxiliary ECU and the engine ECU are powered by a battery and supply currents to the starter relay. When the engine ECU resets the supply of the current to the starter relay because of a voltage drop of the battery during starting of the engine, the auxiliary ECU increases the voltage supplied from the battery using the booster, thereby supplying the current to the starter relay.

Abstract: The wiper driving apparatus module includes: a motor 12 for driving a wiper unit; a wiper ECU 11 for driving the motor 12; a deceleration mechanism (including gears). The two brush DC motor is employed and driven by a pulse width modulation (PWM) signal, in place of the conventional three brush motor wherein brushes are changed in accordance with a wiper operation speed. Therefore, the number of windings is only a number required for a high speed operation of the wiper unit. The high speed operation is implemented by 100% duty PWM signal, while the low speed operation is implemented by reducing the duty. The PWM signal duty is changed in response to a rainfall, windshield surface state and wind pressure which cause the wiping speed fluctuation.

Abstract: A voltage booster device includes a booster circuit for boosting a power source voltage such as a battery voltage, a voltage-suppressing circuit for suppressing operation of the booster circuit when the boosted voltage reaches a predetermined voltage such as a Zener voltage of a Zener diode included in the voltage-suppressing circuit, and a control circuit having a microcomputer for supplying a voltage-boosting signal when the power source voltage is lower than a predetermined minimum voltage. When the power source voltage is lower than the minimum voltage, the power source voltage is boosted. When the boosted voltage reaches the predetermined voltage such as the Zener voltage, the level of the boosted voltage is kept constant at the level of the predetermined voltage.

Abstract: In a condition monitor system for controlling a power supply in a vehicle, a charge/discharge circuit has a capacitor which is discharged in response to each of speed pulses of a speed sensor and periodic pulses of a microcomputer. When none of the pulses are generated due to abnormality, the capacitor is continuously charged without being discharged. When the charge voltage of the capacitor reaches a switching voltage, a relay is turned off to shut off the power supply to various parts in the vehicle. The charge/discharge circuit is commonly used to check generation of the speed pulses and the periodic pulses by setting the switching voltage in accordance with a possible maximum time interval of the speed pulses.

Abstract: When a microcomputer is automatically reset due to uncontrollable process and recovers from reset, a cancel pulse signal is outputted from the microcomputer to a hold circuit to stop supply of a driving current to a relay. This pulse is generated, when a predetermined condition indicative of possibility of battery rundown lasts for a predetermined time. The predetermined condition includes that a hold set condition is detected based on a status signal inputted from the hold circuit; a card key is present in a key slot; a key verification inputted from an immobilizer ECU is not available; a vehicle speed is zero; and an engine revolution is zero.

Abstract: In an on-board control system, a body ECU executes various control operations in response to the supply of power voltage from a battery. There is connected on the power line of the battery a voltage holding circuit which is formed of a capacitor so that the variation of battery voltage slows. A switch input circuit samples the on/off states of external switches periodically under control of a microcomputer. The microcomputer determines a fall of battery voltage, causing the switch input circuit to stop sampling of switch states. Stopping the circuit operation and thus reducing the battery load current slows the voltage fall at the occurrence of collision of vehicle, allowing adequate time to store collision data in a collision memory circuit.

Abstract: A disconnection detecting apparatus for detecting disconnection of lamps includes a resistor, a differential amplifier, a microcomputer, and a charge pump circuit. The resistor is connected to detect current flowing in the lamps. The voltage that appears at the ends of the resistor is applied to the input terminals of the differential amplifier circuit. The microcomputer detects disconnection of the lamps by comparing the output voltage with a reference. The charge pump circuit increases a battery voltage to a boosted voltage. This boosted voltage is supplied to an operational amplifier in the differential amplifier circuit.

Abstract: The wiper driving apparatus module includes: a motor 12 for driving a wiper unit; a wiper ECU 11 for driving the motor 12; a deceleration mechanism (including gears). The two brush DC motor is employed and driven by a pulse width modulation (PWM) signal, in place of the conventional three brush motor wherein brushes are changed in accordance with a wiper operation speed. Therefore, the number of windings is only a number required for a high speed operation of the wiper unit. The high speed operation is implemented by 100% duty PWM signal, while the low speed operation is implemented by reducing the duty. The PWM signal duty is changed in response to a rainfall, windshield surface state and wind pressure which cause the wiping speed fluctuation.

Abstract: A sampling voltage is periodically applied between contacts of a switch of a device to determine a status of the switch. When a CPU is in a sleep state and the status of the switch is determined closed, the CPU is activated. The sampling voltage when the CPU is in the sleep state is adjusted lower than the one when the CPU is in the wakeup state. This reduces power consumption for the switch status determination. The sampling voltage adjusted at the lower level periodically adjusted to a higher level to reduce errors in the determination due to insulation films on the contacts.

Abstract: A disconnection detecting apparatus for detecting disconnection of lamps includes a resistor, a differential amplifier, a microcomputer, and a charge pump circuit. The resistor is connected to detect current flowing in the lamps. The voltage that appears at the ends of the resistor is applied to the input terminals of the differential amplifier circuit. The microcomputer detects disconnection of the lamps by comparing the output voltage with a reference. The charge pump circuit increases a battery voltage to a boosted voltage. This boosted voltage is supplied to an operational amplifier in the differential amplifier circuit.

Abstract: In an on-board control system, a body ECU executes various control operations in response to the supply of power voltage from a battery. There is connected on the power line of the battery a voltage holding circuit which is formed of a capacitor so that the variation of battery voltage slows. A switch input circuit samples the on/off states of external switches periodically under control of a microcomputer. The microcomputer determines a fall of battery voltage, causing the switch input circuit to stop sampling of switch states. Stopping the circuit operation and thus reducing the battery load current slows the voltage fall at the occurrence of collision of vehicle, allowing adequate time to store collision data in a collision memory circuit.

Abstract: In a power window device, a DOWN switch has first and second switches in a power window circuit located in a door for a window of a passenger's seat. A normally-closed contact of the first switch and a remote UP terminal of the power window circuit to which an UP signal is applied from a power window circuit provided near the driver's seat are connected. A normally-closed contact of the second switch and a remote DOWN terminal of the power window circuit to which a DOWN signal is applied from the power window circuit are connected. When the DOWN switch is manually operated, a signal supply line to which the UP signal and the DOWN signal are applied and a power supply line to which a power source is connected are electrically disconnected. As a result, the power window device is operable even when the signal supply line is grounded due to submerging in water.

Abstract: In a multiplex communication system, a communication bus is connected to a communication bus disconnect control device. In the communication bus disconnect control device, a control section generates a communication bus disconnect signal when a trouble of the communication bus is detected. A communication bus disconnect device is provided for separating the communication bus into at least two communication bus groups in response to the communication bus disconnect signal.

Abstract: In a power window device, a DOWN switch has first and second switches in a power window circuit located in a door for a window of a passenger's seat. A normally-closed contact of the first switch and a remote UP terminal of the power window circuit to which an UP signal is applied from a power window circuit provided near the driver's seat are connected. A normally-closed contact of the second switch and a remote DOWN terminal of the power window circuit to which a DOWN signal is applied from the power window circuit are connected. When the DOWN switch is manually operated, a signal supply line to which the UP signal and the DOWN signal are applied and a power supply line to which a power source is connected are electrically disconnected. As a result, the power window device is operable even when the signal supply line is grounded due to submerging in water.

Abstract: To provide a microprocessor that can perform high-speed CRC code generation and can be implemented simply and at a low cost, a microprocessor has, at a part of a data input path to a shift circuit which is conventionally installed in an ALU of the microprocessor to execute shift commands, one bit of data that corresponds to the path, an exclusive OR circuit, which computes the exclusive OR of an uppermost bit of byte data and a bit data, is provided. For this circuit, a result according to a generating polynomial such as [X8+X4+X3+X2+1] is determined on the basis of the installation location of the exclusive OR circuit along the path, and by setting an initial value to the byte data, inputting one bit of the transmission data sequentially to the bit data and operating the shift circuit, a computed result for the CRC code is derived. Consequently, for the microprocessor, the CRC code can be generated at a high speed using the computation commands of the CRC code section.