Gauge Driver Precisely Controls Car Instrumentation Panels

Precise control of vehicle instrument panels such as speedometers, tachometers, fuel gauges and temperature meters is provided by the CS4122 triple air-core gauge driver. The device enables automotive engineers to design information-rich instrumentation displays at a reduced cost by combining the multiple functions in a single device. Complete with serial-to-parallel input bus interface for seamless processor-to air core control, the driver translates a 12-bit digital word provided by a microcontroller into addressable dc outputs that control three air core meters. Equipped with an on-chip SPI port, the device employs a 2-MHz clock frequency to shift input data to the appropriate D/A converter/multiplexer channel. The DAC/MUX provides an accurate tangential conversion to a dc coil voltage representing the digital data, and on-chip output buffer amplifiers deliver 70 mA of drive current to each quadrature coil. Other features include power-on reset, thermal shutdown, and self-protection against output short-circuit conditions. In a 24-lead SOIC package, the device costs $2.55 each/10K.