Buffer Amplifier Feedback Circuit for Low-Power Voltage Gain

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Solution Overview

Problem

Conventional amplifier circuits, particularly those with voltage gain close to one, are limited in their ability to provide substantial voltage amplification and are mainly used as buffer amplifiers, which restricts their application in signal amplification and other electronic systems.

Innovation Solution

The development of amplifier circuits utilizing buffer amplifiers with high input resistance and voltage gain substantially equal to one, along with resistors or capacitors, to achieve continuous-time or discrete-time signal amplification, including configurations that amplify weighted sums or differences of input voltages, and employing buffer-based circuits in analog-to-digital converters to mitigate offset voltage effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a buffer amplifier with voltage gain substantially equal to one is used, then the input resistance is high and power consumption is reduced, but the voltage amplification capability is limited

Engineering Contradiction:
Improvepower consumptionVSAvoidvoltage amplification capability
Core Design Contradiction:
Use of energy by moving objectVSPower

Solution Approach 1:

The invention segments the amplification function into two parts: the buffer amplifier provides high input resistance and voltage buffering (gain ≈ 1), while a separate feedback network (resistors and capacitors) provides the substantial voltage amplification. This segmentation allows each component to optimize its specific function, resolving the contradiction between low power consumption and voltage amplification capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The feedback network acts as an intermediary between the buffer amplifier and the output, enabling substantial voltage amplification without requiring the buffer amplifier itself to provide high gain. The feedback network mediates the voltage amplification function while the buffer amplifier maintains high input resistance and low power consumption.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If conventional amplifier circuits with substantial voltage gain are used, then the voltage amplification capability is improved, but the input resistance is reduced and offset voltage effects increase

Engineering Contradiction:
Improvevoltage amplification capabilityVSAvoidinput resistance and offset voltage effects
Core Design Contradiction:
PowerVSMeasurement precision

Solution Approach 1:

The invention separates the voltage amplification function from the high input resistance function. The buffer amplifier maintains high input resistance and low offset voltage, while the feedback network provides substantial voltage gain. This segmentation resolves the contradiction by allowing each component to optimize its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The feedback network serves as an intermediary that provides voltage amplification without directly loading the input signal source. By placing the feedback network after the buffer amplifier, the high input resistance of the buffer is preserved while still achieving substantial overall voltage gain through the feedback mechanism.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If a buffer amplifier with high input resistance is used, then the loading effect on the signal source is reduced, but the voltage gain is limited to substantially one

Engineering Contradiction:
Improveinput resistanceVSAvoidvoltage gain
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The invention segments the circuit functions so that the buffer amplifier provides high input resistance and voltage buffering, while a separate feedback network provides substantial voltage amplification. This allows the buffer amplifier to maintain its high input resistance property without being limited in the overall system's voltage gain capability.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2974008B1Buffer amplifier circuit
Publication Date: 2021.01.27 LEE HAE SEUNG
  • EP2974008B1 patent drawingFigure 1
  • EP2974008B1 patent drawingFigure 2
  • EP2974008B1 patent drawingFigure 3

AI summary

Amplifier circuits implemented with a buffer amplifier with a voltage gain substantially equal to one. In one example, a continuous-time amplifier is implemented by applying the input source across the input and the output terminals of the buffer amplifier. In another example, a discrete-time amplifier is implemented. During the sampling phase at least one input voltage is sampled, and during the transfer phase at least one capacitor is coupled across the input and the output terminals of a buffer amplifier to effectuate an amplification.