ASK Receiver Threshold Circuit for Low-Power Demodulation
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Solution Overview
Problem
Existing ASK receivers consume excessive power, leading to shortened battery life and violation of power budgets, primarily due to the high bandwidth and power-consuming transconductors used in operational amplifier-based envelope detectors.
Innovation Solution
Implementing an ASK receiver with a matched current mirror, programmable gate-to-source voltage offset, and AC signal injection capacitor to minimize quiescent current while maintaining speed and sensitivity, utilizing a common source amplifier with a transistor and matched current mirror to set a variable threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If operational amplifier-based envelope detectors with high bandwidth transconductors are used, then demodulation performance and speed are improved, but power consumption increases excessively
Solution Approach 1:
The patent changes the operating parameters by using a common source amplifier configuration with specific transistor sizing and biasing conditions. The transconductor is designed to operate at optimal current levels that balance speed and power consumption, rather than using high bandwidth transconductors that consume excessive power. This parameter optimization resolves the contradiction between demodulation speed and power consumption.
2Productivity
If high bandwidth transconductors are used in envelope detectors, then signal processing capability is improved, but the receiver violates power budgets
Solution Approach 1:
The patent optimizes the transconductor parameters including current levels, transistor dimensions, and biasing voltages to achieve adequate signal processing capability within power budget constraints. The common source amplifier configuration provides sufficient gain and bandwidth for ASK demodulation without requiring excessive current, thus maintaining productivity while respecting power limitations.
3Reliability
If conventional envelope detectors are used, then demodulation function is achieved, but quiescent current is high
Solution Approach 1:
The patent modifies the operational amplifier configuration to a common source amplifier with optimized biasing that reduces quiescent current while maintaining demodulation functionality. The biasing circuitry is designed to provide necessary operating points for the transistors at lower current levels, ensuring reliable ASK demodulation with minimized static power consumption.
Data Source
Figure 1A~1B
Figure 2~4
Figure 3
AI summary
An example apparatus includes: a receiver (100) operable to receive a modulated input signal (101) at a receiver input and output a demodulated signal (103) at a receiver output, the receiver (100) comprising a switch (104) 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 (110) 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 (112) 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 (114) having an input and an output, the output coupled to the third terminal. The example apparatus includes a current source (108) coupled to the first current terminal.