Transformer-Coupled Buffer Swing Control Across PVT Corners
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Solution Overview
Problem
The output voltage swing of buffers in mmWave systems varies significantly across process-voltage-temperature (PVT) corners, leading to excess power consumption, signal path gain variation, increased LO leakage, and reliability issues due to current-limited operation.
Innovation Solution
A feedback circuit is employed to detect and control the output voltage swing by adjusting parameters such as regulated voltage or bias current, using a transformer with magnetically coupled inductors and a transconductance driver, to maintain the swing close to a target value, thereby stabilizing the output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If current-limited operation is used in buffers, then power efficiency is improved, but output voltage swing varies significantly across PVT corners
Solution Approach 1:
The patent implements a feedback circuit that detects the output voltage swing of the buffer and adjusts the bias current accordingly. The feedback circuit includes a voltage detector that monitors the output swing and a current controller that modifies the bias current to maintain the swing within a target range, thereby resolving the contradiction between power efficiency and swing stability across PVT corners.
Solution Approach 2:
The patent dynamically changes the bias current parameter based on detected output swing conditions. By adjusting this key parameter in response to PVT variations, the system maintains both power efficiency and stable output voltage swing across different operating conditions.
2Device complexity
If output voltage swing varies across PVT corners, then device complexity is reduced, but signal path gain variation increases
Solution Approach 1:
The feedback circuit continuously monitors output swing and adjusts bias current to compensate for PVT-induced gain variations. This closed-loop control maintains consistent signal path gain without requiring complex pre-compensation circuits, thus resolving the contradiction between device complexity and gain precision.
3Device complexity
If output voltage swing varies across PVT corners, then device complexity is reduced, but LO leakage increases
Solution Approach 1:
The feedback mechanism detects excessive output swing that causes LO leakage and reduces bias current to suppress the swing, thereby reducing LO leakage without requiring complex filtering or isolation circuits.
4Device complexity
If output voltage swing varies across PVT corners, then device complexity is reduced, but reliability decreases
Solution Approach 1:
The feedback circuit ensures reliable operation by continuously monitoring output swing and adjusting bias current to keep the buffer operating within safe margins, preventing distortion and ensuring consistent performance across all PVT corners without adding significant complexity.
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
The feedback mechanism reduces swing variation across PVT corners, mitigating power consumption, signal path gain fluctuations, LO leakage, and reliability issues, ensuring consistent performance.
Implementation Method 1
a transformer with magnetically coupled inductors
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
In certain aspects, an apparatus includes a transformer including an input inductor and an output inductor, wherein the input inductor is magnetically coupled to the output inductor. The apparatus also includes a transconductance driver configured to drive the input inductor based on an input signal. The apparatus further includes a feedback circuit configured to detect an output voltage swing at the output inductor, generate a regulated voltage at the input inductor, and control the regulated voltage based on the detected output voltage swing.