US 5,327,131 A · Parallel A/D converter having comparator threshold voltages defined by MOS transistor geometries

Abstract

A comparator includes a P-channel MOS transistor connected at the source thereof to a power source and at the drain thereof to a comparator output and the drain of an N-channel MOS transistor. The source of the N-channel MOS transistor is connected to the ground. The gates of the P-channel MOS transistor and the N-channel MOS transistor are connected to a comparator input. The logic threshold voltage of the comparator is adjusted in accordance with a circuit parameter regarding the P-channel MOS transistor and the N-channel MOS transistor such as, a gate length, a gate width or a voltage of the power source. A result of comparison by the comparator between an analog input value inputted to the comparator input and the logic threshold voltage of the comparator is outputted to the comparator output. An analog to digital converter is constructed using the comparator. The analog to digital converter is reduced in size and allows high speed analog to digital conversion.

Claims15

Dependent claims

An analog to digital converter for converting an analog input value into a digital output value, the converter comprising:

at least one switching comparator including a switching active element, a comparator output of the at least one switching comparator based on a comparator input of the at least one switching comparator and a predetermined logic threshold voltage, the predetermined logic threshold voltage set to a value within a range of the analog input value by adjusting a circuit parameter of said switching active element, the analog input value input to the at least one switching comparator;
and
determining means for determining the digital output value based on the comparator output of the at least one switching comparator, wherein the predetermined logic threshold voltage of said at least one switching comparator is set based on a combination of a gain, an on or off resistance, a threshold voltage and a supplied voltage of said switching active element.

An analog to digital converter for converting an analog input value into a digital output value, the converter comprising:

at least one switching comparator including a switching active element, a comparator output of the at least one switching comparator based on a comparator input of the at least one switching comparator and a predetermined logic threshold voltage, the predetermined logic threshold voltage set to a value within a range of the analog input value by adjusting a circuit parameter of said switching active element, the analog input value input to the at least one switching comparator;
and
determining means for determining the digital output value based on the comparator output of the at least one switching comparator, wherein the predetermined logic threshold voltage of said at least one switching comparator is set by an adjustable power supply source, the adjustable power supply source connected to said at least one switching comparator.

An analog to digital converter for converting an analog input value into a plurality of digital output values, the converter comprising:

a plurality of comparators, at least one of the comparators including a comparing operation stopping switch;
and
controlling means for turning the comparing operation stopping switch to one of an on state and an off state to shift an operation timing of at least one of said plurality of comparators.

Dependencies are inferred from the claim text.

Parallel A/D converter having comparator threshold voltages defined by MOS transistor geometries

Life of this patent

Parallel A/D converter having comparator threshold voltages defined by MOS transistor geometries

Life of this patent

Abstract

Claims15