Active-Inductor OTA Circuit for Duty Cycle Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Operational transconductance amplifier circuits in DDR5 face distortion due to differing electrical path lengths, which active inductors attempt to mitigate but require high inductance, occupying space and hindering miniaturization, necessitating effective use of active inductors including resistors and capacitors to maintain impedance and improve duty cycle characteristics.
Innovation Solution
The implementation of operational transconductance amplifier circuits that incorporate current mirror circuits with active inductors, specifically using P-channel and N-channel transistors with resistors and capacitors to generate differential currents and mirror currents, thereby correcting duty cycle mismatches and enhancing bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If inductors with high inductances are used to maintain constant impedance at low frequencies, then duty cycle distortion is reduced, but the inductors occupy a large area, hindering miniaturization
Solution Approach 1:
The patent uses active inductors that dynamically adjust their impedance characteristics through controlled current sources and transistors, replacing fixed high-inductance components with active circuits that achieve the same impedance matching function with much smaller area
Solution Approach 2:
The patent substitutes passive magnetic inductors with active electronic circuits comprising transistors, resistors, and capacitors, eliminating the need for large physical inductors while maintaining the required impedance characteristics for duty cycle correction
2Area of stationary object
If active inductors including resistors and capacitors are used instead of traditional inductors, then inductor area is reduced, but circuit complexity increases
Solution Approach 1:
The active inductor circuits perform multiple functions simultaneously: they provide impedance matching, compensate for duty cycle distortion, and maintain constant impedance across frequency ranges, reducing the need for separate compensation circuits and overall system complexity
Solution Approach 2:
The patent integrates the active inductor functionality directly into the operational transconductance amplifier structure, combining impedance control and signal amplification functions in a unified circuit architecture
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
An operational transconductance amplifier (4000) is provided, which comprises an input circuit (2100) configured to generate a first differential current (IDIFF2) and a second differential current (IDIFF1) based on a pair of differential input signals (IN, INB); a first current mirror circuit (2310) configured to generate a first mirror current (IM1) based on the first differential current (IDIFF2); a second current mirror circuit (2320) configured to generate a second mirror current (IM3) based on the second differential current (IDIFF1); and a third current mirror circuit (2330) configured to generate a third mirror current (IM5) based on the second mirror current (IM3), wherein the first current mirror circuit (2310) and the second current mirror circuit (2320) respectively comprise a first active inductor (4100) and a second active inductor (4200) each including a P-channel transistor, and wherein the third current mirror circuit (2330) comprises a third active inductor (4300) including an N-channel transistor.