Amplifier Circuit Topology for Multi-Stage Offset Residue Reduction

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Solution Overview

Problem

Existing amplifier circuits face challenges in efficiently reducing residual voltage to a very low level, particularly at high accuracy requirements, due to high intrinsic offset and decreased dynamic range as technology scales down, leading to issues with offset compensation and gain loss.

Innovation Solution

The amplifier circuit employs a successive-residue-reduction technique using a switching network and capacitors to sequentially reduce residual voltage over a few steps, storing and compensating residual offsets across multiple storage units, allowing for 'stacked-ac-coupling' or 'parallel-dc-coupling' configurations to achieve high accuracy without requiring high voltage gain or digital filtering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If conventional amplifier circuits are used with technology scaling down, then device size is reduced, but intrinsic offset increases and dynamic range decreases

Engineering Contradiction:
Improvedevice sizeVSAvoidintrinsic offset
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The amplifier circuit is divided into multiple residue-reduction stages, each handling a portion of the offset compensation task. The first-stage residue-reduction storage unit and final-stage residue-reduction storage unit separately process different aspects of offset reduction, allowing the system to achieve high precision without requiring a single high-gain stage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The residue-reduction storage units pre-compensate for offset errors before the main amplification process. By storing and subtracting residual voltages in advance through the switching network, the circuit eliminates offset issues before they affect the measurement precision.

Inventive Principle:
Principle #10Preliminary action

2Volume of moving object

If conventional amplifier circuits are used with technology scaling down, then device size is reduced, but dynamic range decreases

Engineering Contradiction:
Improvedevice sizeVSAvoiddynamic range
Core Design Contradiction:
Volume of moving objectVSAdaptability or versatility

Solution Approach 1:

The switching network dynamically reconfigures the circuit between different operational modes: residue-reduction mode and signal amplification mode. This dynamic switching allows the same hardware to perform both offset compensation and signal processing, effectively extending the usable dynamic range despite physical scaling constraints.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If multiple residue-reduction steps are implemented, then residual voltage is reduced to very low level, but circuit complexity increases

Engineering Contradiction:
Improveresidual voltage reductionVSAvoidcircuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The residue-reduction storage units serve multiple functions: they store residual voltages, provide compensation signals, and act as part of the overall amplification pathway. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in circuit complexity despite implementing multiple residue-reduction steps.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Measurement precision

If high voltage gain stages are used to compensate offset, then offset compensation improves, but gain loss increases

Engineering Contradiction:
Improveoffset compensationVSAvoidgain loss
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The offset compensation function is extracted from the main signal amplification pathway and implemented separately through the residue-reduction storage units. This separation allows offset compensation to occur without requiring high voltage gain stages in the signal path, thereby preserving signal gain and reducing energy loss.

Inventive Principle:
Principle #2Taking out (Extraction)

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 enables reaching extremely high accuracy in a few cycles, accommodating incomplete settling and supporting low gain stages, with reduced need for high accuracy digital converters and digital filtering, while effectively compensating for intrinsic offsets and noise.

Implementation Method 1

each comprising a first capacitor that is connected to the first amplifier stage input terminal; and a second capacitor that is connected to the second amplifier stage input terminal

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP4462676A1An amplifier circuit
Publication Date: 2024.11.13 NXP BV
  • EP4462676A1 patent drawingFigure 1a~1b
  • EP4462676A1 patent drawingFigure 2~3
  • EP4462676A1 patent drawingFigure 4a~4b

AI summary

An amplifier circuit (400) comprising: a first-stage residue-reduction storage unit (408); a final-stage residue-reduction storage unit (409); and a switching network (410). The switching network (410) is operable to control the amplifier circuit (400) according to the following operational configurations: a first residue-reduction configuration; a second residue-reduction configuration; and an operational configuration. Such an amplifier circuit advantageously requires a low number of residue-reduction steps to reduce global residual voltage to a very low level when the amplifier circuit is subsequently used in the operational configuration.