Second Generation Building Block Circuits-A Unique New Frequency to Voltage Converter

A new level of electronic building blocks for automotive system design is evolving. These circuits will perform specific functions with high accuracy, low cost, and a minimum of external components. This paper describes a unique frequency to voltage converter designed for the specific interface problems found in automotive systems.

The concept of a building block device requires that a function be performed in the same way as it can be mathematically defined. This device is free of the typical compromises associated with adapting conventional F-V converters to automotive requirements. It interfaces directly with magnetic pickups and its output is directly proportional to frequency even as the frequency goes to zero.

Two specific application areas are explored. The need for an electronic speedometer/tachometer for better reliability and easier instrument panel design calls for a ripple-free low frequency F-V or F-I converter.

At the front of most adaptive braking systems is a wheel speed to voltage conversion. This device can go one step further and provide some of the logic required in multiple input anti-skid systems.