A/D LSI Controller Peripheral Chip

Abstract

A peripheral interface unit in a microcomputer control system fabricated by a standard n-channel silicon-gate enhancement/depletion MOS process is described. The unit, designed so as to meet customized requirements, has the capability of accepting analog and digital input, generating digital output, and multiplying. The analog input capability is made possible by an on-chip A/D converter using a constant slope approach. The use of a current source, a level shifter, and a threshold detector realizes a standard NMOS compatible converter with an external capacitor. The converter, which requires only a small die size, can perform a ten-bit conversion in 5 ms and has an input voltage range from 0 to 5 V with one positive power supply. Large-scale digital circuitry providing various logic functions with a specialized custom architecture is also included in the unit, which is 5.6 mm X 6.2 mm. This converter is especially suited for use in microcomputer control systems for specific consumer and industrial applications.