ASK Receiver Demodulation Circuit With Low-Quiescent Current Mirror

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Amplitude shift keying (ASK) receivers consume excessive power, particularly in low-frequency RF applications, leading to shortened battery life and violating power budgets, due to the high bandwidth and power-consuming nature of operational amplifier full-wave rectifier-based envelope detectors.

Innovation Solution

The implementation of a matched current mirror with a programmable gate-to-source voltage (Vgs) offset and an AC signal injection capacitor in the ASK receiver, which includes a common source amplifier and a voltage offset source, reduces total quiescent current while maintaining sensitivity and speed, and is designed to be two times smaller in silicon area compared to traditional envelope detector-based receivers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If operational amplifier full-wave rectifier-based envelope detector is used, then demodulation function is achieved, but power consumption increases excessively

Engineering Contradiction:

Improvepower consumptionVSAvoiddemodulation function

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent extracts and removes the operational amplifier full-wave rectifier-based envelope detector from the ASK receiver, replacing it with a simpler demodulation circuit that achieves the same demodulation function with significantly lower power consumption, thus resolving the contradiction between power consumption and demodulation function

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the complex, power-consuming operational amplifier-based envelope detector with a simpler, lower-cost demodulation circuit that uses minimal power resources, achieving acceptable demodulation performance at a fraction of the original power cost

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Area of stationary object

If operational amplifier full-wave rectifier-based envelope detector is used, then demodulation is performed, but silicon area increases

Engineering Contradiction:

Improvesilicon areaVSAvoiddemodulation function

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The patent removes the operational amplifier full-wave rectifier-based envelope detector from the circuit design, replacing it with a compact demodulation implementation that occupies significantly less silicon area while maintaining the essential demodulation capability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using the conventional approach of operational amplifier-based envelope detection that consumes large silicon area, the patent inverts the design approach by implementing a simplified demodulation circuit that achieves the same function with minimal area occupation

Inventive Principle:

Principle #13The other way round (Inversion)

3Speed

If high bandwidth operational amplifier is used, then signal processing speed is improved, but power consumption increases

Engineering Contradiction:

Improvesignal processing speedVSAvoidpower consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The patent extracts the high bandwidth operational amplifier from the signal processing path and replaces it with a low-power alternative that maintains adequate signal processing speed for ASK demodulation, eliminating the need for power-consuming high-speed amplification

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies partial action by using a simplified demodulation circuit that processes signals at adequate rather than maximum speed, achieving acceptable signal processing performance with minimal power consumption by avoiding excessive bandwidth requirements

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS20220368576A1Methods and apparatus to demodulate an input signal in a receiver

Publication Date: 2022.11.17 TEXAS INSTRUMENTS INC

AI summary

An example apparatus includes: a receiver operable to receive a modulated input signal at a receiver input and output a demodulated signal at a receiver output, the receiver comprising a switch having a first current terminal and a first control terminal, the first current terminal coupled to the receiver output. The example apparatus includes a capacitor having a first terminal and a second terminal, the second terminal coupled to the first control terminal and the first terminal coupled to the receiver input. The example apparatus includes a resistor having a third terminal and a fourth terminal, the fourth terminal coupled to the first control terminal. The example apparatus includes a voltage offset source having an input and an output, the output coupled to the third terminal. The example apparatus includes a current source coupled to the first current terminal.