Negative Impedance Circuit Using Current Reuse for Wider Bandwidth

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Solution Overview

Problem

Current negative impedance synthesis circuits require additional current consumption, leading to high power consumption and costs, which limits their operating bandwidth and stability in amplifier circuits due to parasitic capacitances.

Innovation Solution

A negative impedance synthesis circuit that reuses current by incorporating a current source circuit, a differential circuit, and a negative impedance conversion circuit, where the negative impedance conversion circuit is connected in parallel to the differential output port, achieving the negative capacitance effect using partial current from the differential circuit, thus eliminating the need for additional current consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a negative impedance conversion circuit is added to compensate for parasitic capacitance, then the operating bandwidth is improved, but the power consumption increases due to additional current consumption

Engineering Contradiction:

Improveoperating bandwidthVSAvoidpower consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The patent combines the negative impedance conversion circuit with the existing amplifier circuit by sharing the bias current. The current source circuit provides a single bias current that is reused by both the differential pair and the negative impedance conversion circuit, eliminating the need for separate current sources and reducing total power consumption while maintaining bandwidth enhancement.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The bias current from the current source circuit serves multiple functions simultaneously: it provides the operating current for the differential pair and also supplies the current needed for the negative impedance conversion circuit to generate negative capacitance. This multi-functional use of the same current source reduces overall power consumption.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Speed

If a negative impedance conversion circuit is added to compensate for parasitic capacitance, then the operating bandwidth is improved, but the circuit complexity increases

Engineering Contradiction:

Improveoperating bandwidthVSAvoidcircuit complexity

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The patent merges the negative impedance conversion circuit with the amplifier circuit architecture by sharing common components (current source, reference voltages) and coupling them through the differential output. This integration reduces the number of independent circuits and simplifies the overall system while achieving bandwidth extension.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If additional current is consumed by the negative impedance conversion circuit, then the negative capacitance effect is achieved, but the cost increases

Engineering Contradiction:

Improvenegative capacitance effectVSAvoidcurrent consumption

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The negative impedance conversion circuit uses the bias current already present in the amplifier circuit to generate the negative capacitance effect. The current source circuit automatically provides the necessary current to both the differential pair and the negative impedance conversion circuit, making the system self-sufficient without requiring additional external current sources.

Inventive Principle:

Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach increases the bandwidth of the negative impedance synthesis circuit while reducing power consumption and costs, without additional current consumption, and allows for fine-tuning of frequency response by adjusting the capacitance value.

Implementation Method 1

the negative impedance conversion circuit may achieve the negative capacitance effect by using partial current of the differential circuit

Methodology Applied

Scientific EffectNegative capacitance effect:

Data Source

PatentUS11677359B2Circuit which reuses current to synthesize negative impedance

Publication Date: 2023.06.13 REALTEK SEMICON CORP

AI summary

A circuit which reuses current to synthesize a negative impedance includes a current source circuit, a differential circuit, and a negative impedance conversion circuit. The current source circuit is arranged to provide at least one predetermined current, wherein the current source circuit has a first connection port and a second connection port, and the first connection port of the current source is coupled to a first reference voltage. The differential circuit is coupled between the second connection port of the current source circuit and a second reference voltage, and is arranged to receive a differential input pair and generate a differential output pair, wherein the differential circuit has a differential output port. The negative impedance conversion circuit is coupled between the differential output port and a third reference voltage, wherein the third reference voltage is different from the first reference voltage.