Current-Output Gain Stage for Direct ADC Input Coupling
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Solution Overview
Problem
Existing gain stage circuits require additional circuitry to convert output voltage to current for subsequent ADC circuits, which increases power consumption and circuit area, and often include unnecessary operational amplifier stages.
Innovation Solution
The gain stage is modified to directly output current from a current output node to the input of an ADC circuit, removing the need for a second operational amplifier stage and input resistor, allowing for a more efficient power usage and reduced circuit area by using a current mirror stage and transconductance conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a voltage-based ADC circuit is used with a gain stage, then the output voltage can be converted to digital signal, but additional circuitry is required to convert output voltage to current, increasing power consumption and circuit area
Solution Approach 1:
The patent extracts and removes the unnecessary second operational amplifier stage and input resistor from the conventional gain stage configuration. By taking out these redundant components, the circuit directly outputs current to the current-based ADC without requiring voltage-to-current conversion circuitry, thereby reducing power consumption while maintaining ADC conversion capability.
Solution Approach 2:
The gain stage is designed to directly provide current output that can be universally applied to current-based ADC circuits. The single operational amplifier stage with current mirror configuration serves multiple functions: amplification, current conversion, and direct ADC interface, eliminating the need for separate voltage-to-current conversion circuitry and reducing overall power consumption.
2Measurement precision
If a voltage-based ADC circuit is used with a gain stage, then the output voltage can be converted to digital signal, but additional circuitry is required to convert output voltage to current, increasing circuit area
Solution Approach 1:
The patent extracts and removes the unnecessary second operational amplifier stage and input resistor from the conventional gain stage configuration. By taking out these redundant components, the circuit directly outputs current to the current-based ADC without requiring voltage-to-current conversion circuitry, thereby reducing circuit area while maintaining ADC conversion capability.
Solution Approach 2:
The patent merges the voltage amplification and current conversion functions into a single operational amplifier stage with current mirror configuration. This consolidation eliminates the need for separate voltage-to-current conversion circuitry, reducing the overall circuit area while maintaining the capability to drive ADC circuits.
3Power
If a conventional gain stage with two operational amplifier stages is used, then voltage amplification is achieved, but circuit complexity and power consumption increase
Solution Approach 1:
The patent extracts and removes the unnecessary second operational amplifier stage from the conventional gain stage configuration. By taking out this redundant stage, the circuit achieves the required amplification with a single operational amplifier stage combined with a current mirror, thereby reducing circuit complexity and power consumption while maintaining amplification capability.
Solution Approach 2:
The patent changes the output parameter of the gain stage from voltage to current by modifying the operational amplifier configuration and adding a current mirror. This parameter change allows the single-stage amplifier to directly drive current-based ADC circuits, reducing circuit complexity and power consumption while maintaining the required amplification capability.
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 configuration improves power efficiency and reduces circuit area by enabling direct current output to ADC circuits, enhancing the performance of gain stage circuits in applications like instrumentation amplifiers and sigma-delta ADCs.
Implementation Method 1
a current mirror stage coupled with an output of the first operational amplifier stage, the current output node coupled with the current mirror stage
Data Source
AI summary
A gain stage, such as an amplifier, e.g., an instrumentation amplifier, can receive an input signal and adjust the level of the input signal, e.g., amplify or attenuate. An output voltage of the gain stage can be applied to a subsequent circuit. Using various techniques, a second stage of an instrumentation amplifier, which can include a transconductance stage that converts a current to a voltage that can be applied to an output node of the instrumentation amplifier, can be removed. Removal of such a second stage can allow an output current from the gain stage to be applied directly from a current output node to an input node of a subsequent circuit.