Calibrated Linear-in-dB Log Amplifier for Low-Power Detection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional power detectors face limitations in low power operation due to mismatches caused by PVT variations and system noise, leading to poor transmission quality and multi-path issues, and are unsuitable for mm-wave implementations due to high power consumption and large area requirements.

Innovation Solution

A linear-in-dB log-amp with calibration is implemented, featuring a log amplifier and a calibration circuit that cancels input offset when no power is present, extending the working range and improving sensitivity through offset cancellation and programmable components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional power detectors are used, then power detection function is provided, but sensitivity is limited at low power operation due to offset mismatches

Engineering Contradiction:

Improvepower detection sensitivityVSAvoiddetection accuracy at low power

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The calibration circuit performs offset cancellation before power detection by disconnecting the input power and adjusting the offset cancellation circuit to eliminate mismatches. This preliminary calibration action ensures that subsequent low-power measurements are not degraded by fixed offset errors, thereby improving both sensitivity and detection accuracy at low power levels.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If linear-in-mag power detector with digital log correction is implemented, then power detection is achieved, but circuit area and complexity increase

Engineering Contradiction:

Improvepower detection capabilityVSAvoiddigital circuitry area

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent replaces digital log correction circuitry with an analog logarithmic amplifier that directly outputs a voltage proportional to the logarithm of the input power. This substitution eliminates the need for large digital signal processing circuits while maintaining power detection precision, thereby reducing the overall circuit area and complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If saturation-based linear-in-Db power detector is used in mm-wave implementation, then power detection is provided, but power consumption and area requirements increase

Engineering Contradiction:

Improvelinear-in-Db power detectionVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent employs a calibration circuit that adjusts operating parameters (offset voltages) to optimize the detector's performance at lower power consumption levels. By dynamically calibrating the offset cancellation circuit based on measured mismatches, the system maintains accurate linear-in-Db power detection while reducing the power consumption required for saturation-based operation.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10763913B1Linear-in-dB log-amp with calibration for power detection

Publication Date: 2020.09.01 AXIRO SEMICONDUCTOR INC

AI summary

An apparatus includes a log amplifier and a calibration circuit. The log amplifier may be configured to generate an output signal in response to an offset between a first voltage and a second voltage. The calibration circuit may be configured to disconnect an input power and perform a cancellation of the offset when the input power is not present. The first voltage may be generated by the apparatus in response to a power detection. The second voltage may be received from a reference circuit. The cancellation of the offset may extend a working range of the apparatus. The output may provide a linear-in-dB power detection.