Wideband Buffer Circuit With Cross-Coupled Bandwidth Expansion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wideband wired data communication systems face challenges in power consumption and efficiency due to the need for multiple signal processing stages, with intermediate buffers often consuming more power than equalizers and amplifiers, especially in low-voltage systems.
Innovation Solution
A wideband buffer circuit design incorporating transistors, parallel resistor-capacitor pairs, cross-coupled transistors, and current sources, which provides signal buffering and level shifting while reducing power consumption through negative capacitance for bandwidth expansion and DC level adjustment, eliminating the need for additional gain stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an intermediate buffer is added between signal processing stages, then signal buffering and level shifting are improved, but power consumption increases
Solution Approach 1:
The patent changes the operating parameters of the buffer circuit by using cross-coupled transistors configured to operate in specific regions, adjusting bias conditions and transistor sizing to achieve optimal power consumption while maintaining buffering performance. The cross-coupled configuration allows the buffer to operate with lower power by utilizing the inherent gain and isolation properties of the cross-coupled transistor pair.
2Reliability
If multiple signal processing stages are used, then signal equalization and amplification are improved, but device complexity increases
Solution Approach 1:
The patent combines multiple functions into a single buffer circuit stage. The cross-coupled transistor configuration simultaneously provides buffering, level shifting, and signal equalization that would traditionally require separate stages. This merging of functions reduces the overall number of processing stages while maintaining signal quality and equalization performance.
Solution Approach 2:
The buffer circuit is designed to perform multiple functions simultaneously: it acts as a voltage buffer, provides level shifting, and contributes to signal equalization. This multi-functional design eliminates the need for separate dedicated circuits for each function, thereby reducing device complexity while maintaining comprehensive signal processing capability.
3Power
If buffer gain is increased to compensate for losses, then signal strength is improved, but power consumption increases
Solution Approach 1:
The cross-coupled transistors act as an intermediary mechanism that provides signal amplification through their mutual coupling rather than through direct high-power consumption paths. The cross-coupling creates a regenerative effect where each transistor amplifies the signal for the other, achieving high signal strength with lower overall power consumption compared to traditional single-stage amplifiers.
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
Embodiments of a wideband buffer circuit and a wideband communication circuit that uses the wideband buffer circuit are disclosed. In an embodiment, the wideband buffer circuit includes first and second transistors deployed as a voltage buffer and connected to first and second input terminals, first and second parallel resistor-capacitor pairs connected to the first and second transistors, first and second cross-coupled transistors connected to the first and second parallel resistor-capacitor pairs and connected to first and second output terminals, and first and second current sources connected to the first and second cross-coupled transistors and a fixed voltage. The first transistor, the first parallel resistor-capacitor pair, the first cross-coupled transistor and the first current source are connected in series. Similarly, the second transistor, the second parallel resistor-capacitor pair, the second cross-coupled transistor and the second current source are connected in series.