Pipeline ADC Reference Circuit for Inter-Stage Gain Error Reduction
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Solution Overview
Problem
Pipeline analog-to-digital converters (ADCs) face inter-stage gain errors due to mismatches in reference voltages between stages, leading to inaccurate digital outputs, decreased signal-to-noise ratio, and increased harmonic distortion.
Innovation Solution
The implementation of a pipeline ADC with reference generation circuitry that generates a low voltage reference proportional to a high voltage reference, reducing inter-stage gain errors by ensuring the low voltage reference is proportional to the high voltage reference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a pipeline ADC uses multiple stages with different reference voltages to achieve high-speed conversion, then conversion speed is improved, but inter-stage gain errors increase due to reference voltage mismatches
Solution Approach 1:
The patent changes the reference voltage parameter by generating a low voltage reference that is precisely proportional to the high voltage reference through a voltage divider network. This ensures that the reference voltage relationship between stages is maintained accurately, eliminating inter-stage gain errors while preserving high-speed conversion capability
Solution Approach 2:
The patent introduces an intermediary voltage divider network consisting of resistors and capacitors that mediates between the high voltage reference and the low voltage reference. This intermediary circuit ensures precise proportional relationship and eliminates direct mismatches between reference voltages of different stages
2Device complexity
If reference voltage mismatches occur between stages, then device complexity is reduced, but signal-to-noise ratio decreases and harmonic distortion increases
Solution Approach 1:
The patent precisely controls the reference voltage parameter through a voltage divider network with carefully selected resistor and capacitor values. This ensures the low voltage reference is exactly proportional to the high voltage reference, eliminating the harmful effects of reference mismatches on signal quality
Solution Approach 2:
The voltage divider network acts as an intermediary that precisely establishes the proportional relationship between reference voltages. By using matched resistors and capacitors, the network ensures accurate voltage division without introducing additional noise or distortion
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces inter-stage gain errors, leading to more accurate digital outputs, improved signal-to-noise ratio, and reduced harmonic distortion in pipeline ADCs.
Implementation Method 1
a capacitor coupled in parallel to the second resistor by a switch
Implementation Method 2
a first resistor coupled to the reference voltage; a second resistor coupled to the first resistor
Data Source
AI summary
An example analog-to-digital converter (ADC) comprising: sample and hold circuitry coupled to an analog input; a first sub-ADC coupled to the sample and hold circuitry; a multiplying digital-to-analog converter (M-DAC) coupled to the first sub-ADC; summation circuitry coupled to the sample and hold circuitry and the M-DAC; an amplifier coupled to the summation circuitry; a second sub-ADC coupled to the amplifier; and reference generation circuitry coupled to the first sub-ADC, the M-DAC, and the second sub-ADC, the reference generation circuitry including: reference voltage circuitry coupled to the M-DAC; a first resistor coupled to the reference voltage circuitry; a second resistor coupled to the first resistor; and a capacitor coupled in parallel to the second resistor by a switch.