Switched Capacitor Sub-Ranging ADC Without Buffer Amplifiers
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Solution Overview
Problem
Conventional sub-ranging ADCs require amplifier circuits to produce error voltages, which can be inefficient and may introduce additional errors, and they do not effectively utilize energy from green sources efficiently.
Innovation Solution
A switched capacitor circuit with a controller that stores input and reference voltages in capacitors, deriving an error voltage to be processed by a delay line ADC, which includes calibration circuits to adjust for gain and offset errors, eliminating the need for buffer amplifiers and optimizing energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If amplifier circuits are used to produce error voltage in conventional sub-ranging ADCs, then the error voltage can be generated, but the circuit complexity increases and additional errors are introduced
Solution Approach 1:
The patent extracts the amplifier function from the error voltage generation process and replaces it with a switched capacitor circuit. The capacitor directly generates the error voltage through switching operations, eliminating the need for separate amplifier circuits and reducing overall device complexity while maintaining error voltage accuracy.
Solution Approach 2:
The patent substitutes the electrical amplification mechanism with a capacitive switching mechanism. Instead of using active amplifier components to generate error voltage, the system uses passive capacitors controlled by switches, replacing an active electrical system with a passive switching system that achieves the same function with fewer components.
2Ease of operation
If buffer amplifiers are used in sub-ranging ADCs, then signal buffering is provided, but energy consumption increases
Solution Approach 1:
The patent removes the buffer amplifier component from the signal path and replaces its function with direct capacitor-to-capacitor charge transfer. The switching circuitry provides the necessary signal isolation and buffering without requiring active amplification, significantly reducing energy consumption while maintaining signal integrity.
Solution Approach 2:
The capacitors in the switched capacitor circuit perform multiple functions simultaneously - they store charge, provide signal buffering, and generate error voltages without requiring separate dedicated components. This self-service approach eliminates the need for separate buffer amplifiers and reduces overall energy consumption.
3Reliability
If conventional amplifier-based error voltage generation is used, then error voltage is produced, but charge sharing losses increase
Solution Approach 1:
The patent replaces the amplifier-based error voltage generation with a switched capacitor mechanism. This substitution eliminates the charge sharing losses inherent in amplifier circuits because capacitors can transfer charge directly without the resistive losses and charge redistribution problems that occur in amplifier-based systems.
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
The solution minimizes charge sharing losses and eliminates the need for buffer amplifiers, providing efficient energy use and accurate conversion with reduced conversion time.
Implementation Method 1
store a sample of an analog input voltage in a first capacitor of the multiple capacitors; store a sample of a first reference voltage in a second capacitor of the multiple capacitors
Data Source
AI summary
An apparatus as discussed herein can be configured to include a first analog-to-digital converter operative to convert a first analog voltage into a first digital signal; a digital-to-analog converter operative to convert the first digital signal into a second analog voltage; a switched capacitor circuit coupled to the digital-to-analog converter, the switched capacitor circuit is operative to store a sample of the second analog voltage; and a second analog-to-digital converter operative to convert an analog error voltage into a second digital signal, the analog error voltage based on a difference between the sample of the second analog voltage received from the switched capacitor circuit and a sample of the first analog voltage.