Anden Co., Ltd.

Denso Corporation

Other

Shigekazu Sugimoto

Yoshichika Abe

Nobutomo Takagi

Fukuo Ishikawa

Junji Hayakawa

Kazunori Ozawa

Hiroshi Yagyu

Takeyoshi Hisada

Koichi Watanabe

Takeshi Hattori

Takaharu Futamura

A switch device controls a voltage applied to a load element according to an electric power supply from a power source. A driver circuit controls activation and deactivation of the switch device. A circuit portion sets a duty ratio and output the duty ratio to the driver circuit for causing the driver circuit to activate the switch device according to the duty ratio to control a voltage applied to the load element. The circuit portion sets the duty ratio according to a duty ratio characteristic curve. In the duty ratio characteristic curve, the duty ratio decreases gradually with increase in a voltage of the power source, and decrease in the duty ratio with increase in the voltage of the power source becomes small gradually.

Load control circuit

An overcurrent protection circuit includes a load driver for driving a load, a controller for turning ON and OFF the load driver, a current sensor for measuring a load current flowing through the load, and an add/subtract circuit for performing both an addition operation and a subtraction operation on a previous calculation result or for performing only the subtraction operation on the previous calculation result so as to produce a present calculation result. The addition operation uses an added value depending on the presently measured current. The subtraction operation uses a subtracted value depending on the presently measured current. The controller turns OFF the load driver, when the present calculation result of the add/subtract circuit exceeds a predetermined determination value.

Overcurrent protection circuit

A first overcurrent detecting circuit outputs a first time-up signal when a time period, in which an electric current flowing into the wire harness is greater than the first threshold, reaches a first duration time, which corresponds to a first threshold. A second overcurrent detecting circuit outputs a second time-up signal when a time period, in which an electric current flowing into the wire harness is greater than the second threshold, reaches a second duration time, which corresponds to a second threshold. The second threshold is less than the first threshold. The second duration time is longer than the first duration time. A determination circuit determines that an overcurrent flows into the wire harness and cause a control circuit to deactivate the switching element when inputting at least one of the first and second time-up signals.

Switch circuit having overcurrent detection function

An electronic circuit device has a current correction circuit that supplies a correction current which is capable of offsetting an increment or a decrement of a consumption current of a signal processor circuit that varies based on a signal level of an input signal. Therefore, even if the consumption current of the signal processor circuit varies based on the signal level of the received input signal, the variation of the consumption current is offset by the current correction circuit. As a result, even if the consumption current varies based on the signal level of the input signal, since a current that flows in a resistor does not vary, a voltage drop can be held constant. Accordingly, it is possible to accurately conduct a comparison determination by a comparator.

Electronic circuit device

An indicator system having light emitting diode (LED) indicators and an open-circuit detecting circuit. In the open-circuit detecting circuit, a voltage at a point between a constant current source and the first resistor is applied to a base of a transistor. The second resistor is connected in parallel between the base and an emitter of the transistor. The third and the fourth resistors are connected in series between the constant current source and a collector of the transistor. The fifth resistor is connected between the emitter of the transistor and the first resistor. The threshold determining circuit determines a voltage at a point between the third and the fourth resistors as a threshold voltage. With this configuration, the threshold voltage can be adjusted according to the resistance of the first resistor.

Indicator system having multiple LEDs

A flasher circuit included in a vehicular turn signal indicator system has a flashing control circuit, a flashing relay, a current detecting resistor, and a switching circuit. The control circuit detects a voltage drop across the resistor during driving of light bulb indicator lamps and light emitting diode (LED) indicator lamps of the system. Each LED lamp is configured to output a disconnection signal if at least one of their LEDs is disconnected during the driving. The signal turns on a transistor of a switching circuit, resulting in short across the resistor. As a result, the voltage drop is lowered equal to or under the threshold value, and the control circuit starts the disconnection detection.

Vehicular turn signal indicator system and flasher circuit for the same

Left and right turn lamps are used as lamps in a daytime travel of a vehicle. When a first daytime turn-on requirement is satisfied, i.e., when an ignition switch is ON, a left-hand contact of a turn switch is OFF, a right-hand contact thereof is off, and the like, a left front turn lamp and a right front turn lamp are turned on as the lamps in the daytime travel, based on signals outputted from first and second AND logic circuits. When the left-hand contact of the turn switch is turned on in this state, the left front turn lamp flashes, based on a signal outputted from a flasher circuit, whereas the right front turn lamp keeps a turn-on state. On the other hand, when the right-hand contact of the turn switch is turned on, the right front-turn lamp flashes, based on a signal outputted from the flasher circuit, whereas the left front turn lamp keeps a turn-on state.

Direction-indication-lamp control apparatus for vehicle

A driving circuit for the electromagnetic relay provides a coil of the electromagnetic relay with stepped voltage having a first voltage which is slightly larger than a minimum operating voltage which caused the coil to generate magnetic field capable of closing contacts of the electromagnetic relay and a second voltage higher than the first voltage, in response to a triggering signal to trigger the electromagnetic relay. According to this structure, because the first voltage lower than the second voltage is applied to the coil firstly, the contacts are closed by attracting force of the coil risen gently. As a result, the bouncing of the moving contact can be prevented. In addition, the response time required for the closing of the contacts can be prevented to become long.

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Takahama, Japan

Shigekazu Sugimoto