Multi-stage analogue-to-digital conversion using half-flash A=D converter - using comparison voltages from one stage as range limiting voltages of subsequent stage

摘要

Two parallel converters (PU1, PU2) and a selector circuit (RW1) afford very rapid conversion by the half-flash method even for curved conversion characteristics. The reference voltage for limiting the range of the second stage (PU2) is selected by the circuit (RW1) from among the comparison voltages used in the first stage (PU1). Eight analogue switches (S0-S7) are shared between two buffer amplifiers (B0, B1) feeding opposite ends of the resistor chain (R20-R23) of the following converter stage. ADVANTAGE - Simple circuit dispensing with any additional D/A converter overcomes limitations of speed, linearity and precision in conventional conversion.