Search Results

In the field of automotive body electronic control such as control of door locks, power windows, and wipers, there is a growing need of multiplexing communication to reduce the amount of wire harnesses. To meet this need, we developed a multiplexing communication protocol particularly suited to the body electronic control. Based on the developed protocol, we designed a communication control IC and a simple driver/receiver circuit with a few discrete components. The bus access method of the communication is the CSMA/CD with nondestructive bit arbitration, and its bit rate is 5 kbps. Its transmission media is a single wire. The communication IC has a multiplexing control block and a serial I/O block for an interface with a host CPU. It was fabricated using CMOS technology and has a chip of 2.6mm x 3.0mm in size that contains about 5,000 transistors. The driver/receiver circuit consists of one transistor, one capacitor and several resistors.

A smart analog integrated circuit (IC) is developed for use in an electronic control unit for an automotive variable power-steering system. This IC accepts a vehicle speed signal as its input, performs signal processings such as frequency to voltage conversion and function generation, and then as its output generates a pulse width modulated (PWM) signal whose duty corresponds precisely to a given piecewise linear function of the vehicle speed. The PWM output is used as a driving signal to a power MOSFET for the actuation and control of a linearly variable solenoid valve to vary the force needed for steering effort in a prescribed relation to the vehicle speed. The IC is fabricated by monolithic bipolar integrated circuit technology and has about 750 device elements in a chip size of 5.7 by 3.1 mm2. It is enveloped in a shrinked dual in-line package with 24 pins.