Passive Equalizer Negative Impedance High-Frequency Gain
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Solution Overview
Problem
Passive equalizers in high-speed serial communication links, such as HDMI, have limited high-frequency gain and poor signal restoration capabilities due to their design, which restricts their flexibility and effectiveness.
Innovation Solution
A passive equalizer design incorporating a first and second RC loop, a cascade RL circuit, and cross-coupled inverter units that utilize negative impedance to enhance high-frequency gain by acting as an equivalent voltage source, assisting passive elements with minimal current consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a typical passive equalizer is used, then the circuit structure is simple, but the high-frequency gain is restrained and signal restoration capability is poor
Solution Approach 1:
The patent merges passive RC loops with active inverter units to create a hybrid equalizer structure. The inverter units are integrated into the signal path between RC loops, combining the simplicity of passive elements with the signal amplification capability of active devices to achieve both high-frequency gain improvement and maintained circuit simplicity.
Solution Approach 2:
The patent changes the impedance parameter of the equalizer by introducing inverter units with negative impedance characteristics. This parameter change allows the equalizer to achieve higher high-frequency gain while maintaining a relatively simple circuit structure, as the negative impedance compensates for the gain loss in passive elements.
2Power
If a typical passive equalizer is used, then the circuit is simple, but the high frequency gain is close to -0.5 dB which is insufficient
Solution Approach 1:
The inverter units act as intermediary elements between the RC loops, providing signal amplification and impedance transformation. These intermediary components enable the equalizer to achieve higher high-frequency gain by mediating the signal between the passive RC sections without requiring a complete redesign of the entire equalizer structure.
3Adaptability or versatility
If passive elements are used, then the device is simple, but the feature values cannot be easily adjusted resulting in lost flexibility
Solution Approach 1:
The patent introduces dynamic adjustment capability through the inverter units, which can be configured to provide different amounts of gain and impedance transformation. This dynamic element allows the equalizer to adapt to different signal conditions and requirements without requiring a complete redesign, thereby improving flexibility while maintaining relative simplicity.
Data Source
AI summary
A passive equalizer with negative impedance to increase a gain includes a first RC loop, a second RC loop, a cascade RL circuit and a cross-coupled inverter unit. Each of the first and the second RC loops includes a first resistor, a second resistor connected in series to the first resistor at a node to thereby form a resistor series, and a capacitor connected in parallel to the resistor series. The cascade RL circuit is connected between the RC loops and includes a fifth resistor, a sixth resistor and an inductor connected between the fifth resistor and the sixth resistor. The cross-coupled inverter unit is connected in parallel to the RL circuit and connected between the RC loops for using the feature of negative impedance to obtain an excellent high-frequency gain.