US 4,903,028 A · Analog-to-digital converter

Abstract

An analog-to-digital converter for converting an analog input voltage signal to a digital output voltage signal of m upper bits and n lower bits which has a plurality of resistors connected in a series circuit to a voltage source for establishing respective reference voltages, an upper bit encoder having a first input receiving the analog input voltage and second inputs connected to the series circuit at respective intervals defining groups of the resistor therebetween for generating the m upper bits and a switch control signal, each of the groups including a plurality of the resistors, a first lower bit encoder having a first input receiving the analog input voltage signal and second inputs for generating the n lower bits, a second lower bit encoder having a first input receiving the analog input voltage signal and second inputs for generating the n lower bits, a switch circuit associated with each of the groups of the resistors and responsive to the switch control signal for selectively connecting each of the second inputs of the first and second lower bit encoders to respective resistors in the associated group of the resistors, and a circuit for alernately combining the m upper bits with the n lower bits generated by the first and second lower bit encoders and for generating the digital output voltage signal.

Claims8

Dependent claims

An analog-to-digital converter for converting an analog input voltage signal to a digital output voltage signal of m upper bits and n lower bits, comprising:

a plurality of resistor means connected in a series circuit to a voltage source for establishing respective reference voltages;
upper bit encoder means having a first input receiving said analog input voltage and second inputs connected to said series circuit at respective intervals defining groups of said resistor means therebetween for generating said m upper bits and a switch control signal, each of said groups including a plurality of said resistor means;
first lower bit encoder means having a first input receiving said analog input voltage signal and second inputs for generating said n lower bits;
second lower bit encoder means having a first input receiving said analog input voltage signal and second inputs for generating said n lower bits;
switch means associated with each of said groups of said resistor means and responsive to said switch control signal for selectively connecting each of said second inputs of said first and second lower bit encoder means to respective resistor means in said associated group of said resistor means, and
means for alternately combining said m upper bits with said n lower bits generated by said first and second lower bit encoder means, and for generating said digital output voltage signal.

3 more elements

An analog-to-digital converter for converting an analog input voltage signal to a digital output voltage signal of m upper bits and n lower bits, comprising:

a plurality of resistor means connected in a series circuit to a voltage source for establishing respective reference voltages;
upper bit encoder means having a first input receiving said analog input voltage and second inputs connected to said series circuit at respective intervals defining groups of said resistor means therebetween for generating said m upper bits and a switch control signal, each of said groups including a plurality of said resistor means;
lower bit encoder means having a first input receiving said analog input voltage signal, second inputs and third inputs for generating said n lower bits;
switch means associated with each of said groups of said resistor means and responsive to said switch control signal for selectively connecting each of said second inputs of said lower bit encoder means to respective resistor means in said associated group of said resistor means and for selectively connecting each of said third inputs of said lower bit encoder means to a predetermined number of said resistor means adjoining to and outside said associated group of said resistor means;
and
means responsive to an output signal from said lower bit encoder means for adding 1 to or subtracting 1 from said m upper bits when said analog input voltage signal corresponds to said reference voltages supplied to said third inputs of said lower bit encoder means.

3 more elements

Dependencies are inferred from the claim text.

Analog-to-digital converter

Life of this patent

Analog-to-digital converter

Life of this patent

Abstract

Claims8