Full Wave Rectifier Circuit for Differential Signal Detection
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Solution Overview
Problem
Existing high-speed serial data communication systems require preamplifiers to provide common mode voltage immunity in signal detection circuits, leading to significant power dissipation due to the need for continuous operation at high data rates.
Innovation Solution
A full-wave rectifier circuit with a pair of differential input circuits using field effect transistors of different conductivity types, coupled with a reference voltage source having a common circuit configuration, provides high common mode noise immunity, eliminating the need for a preamplifier by generating a signal at an output node responsive to differential input signals while compensating for common mode effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a preamplifier is used to provide common mode voltage immunity in signal detection circuits, then common mode immunity is improved, but power dissipation increases due to continuous operation at high data rates
Solution Approach 1:
The patent extracts and eliminates the preamplifier component from the signal detection circuit. By using a full-wave rectifier with differential input circuits that directly process differential signals, the design removes the power-consuming preamplifier stage while maintaining common mode rejection through the inherent differential architecture and full-wave rectification process
Solution Approach 2:
The patent changes the operating parameters of the signal detection circuit by using field effect transistors with different conductivity types (N-channel and P-channel) in the differential input circuits. This parameter change enables the circuit to achieve high common mode immunity through the complementary action of the transistors while consuming less power compared to traditional preamplifier-based designs
2Measurement precision
If high-speed comparators and preamplifiers are used for signal detection, then detection accuracy is improved, but power consumption increases
Solution Approach 1:
The patent removes high-speed comparators and preamplifiers from the signal detection path. Instead, it employs a full-wave rectifier circuit with differential input stages that directly detect and rectify differential signals, achieving accurate signal detection without the power penalty of traditional high-speed comparator-based architectures
Solution Approach 2:
The differential input circuits with field effect transistors of different conductivity types perform self-biasing and self-regulation. The complementary N-channel and P-channel transistors automatically balance the circuit operation and maintain detection accuracy through their inherent electrical characteristics, eliminating the need for external high-power amplification and comparison stages
Data Source
AI summary
A full wave rectifier (270) for use as part a differential signal detector (400) detects both high and low envelopes of differential signals (RXa, RXb) at a pair of differential inputs (202, 204) and provides a sense signal (VSENSE) at an output (220) thereof. The differential signal detector (400) includes both the full wave rectifier (270) and a voltage reference source (260) having a circuit architecture in common, and a comparator for comparing the sense signal (VSENSE) with a reference voltage (VREF). The circuit configuration of both the full wave rectifier (270) and the voltage reference source (260) include first and second differential input circuits (271 and 273, 261 and 263) each including a pair of field effect transistors (2722, 2742 and 2762, 2782; 2622, 2642 and 2662, 2682) of different conductivity type having respective source terminals (2728, 2748; 2768, 2788; 2628, 2648; 2668, 2688) coupled together.