Triangular Wave Generator Current Source for PVT-Stable VR PWM
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Computing devices face challenges in efficiently supplying power using voltage regulators (VRs) due to non-linear relationships between output voltage and switching frequency, resulting in systemic and random offsets that affect the accuracy of waveform generators, leading to yield loss and inefficiencies.
Innovation Solution
Implementing a current source with a switched-capacitor frequency-to-current converter, incorporating a switching circuit, continuous-time integrator, and adaptive multi-stage filter to provide a clean current to the waveform generator, utilizing capacitors with corresponding PVT variations to reduce ripple and improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional current source is used in the waveform generator, then the circuit is simpler, but the output current has significant ripple and is highly sensitive to PVT variations, resulting in non-linear behavior and reduced accuracy
Solution Approach 1:
The current source is divided into multiple functional blocks: switching circuit (620), continuous-time integrator (610), and adaptive multi-stage filter (630). Each block performs a specific function to progressively clean the current signal and compensate for PVT variations, transforming a single complex circuit into manageable segments that collectively achieve high accuracy.
Solution Approach 2:
The continuous-time integrator acts as an intermediary between the switching circuit and the adaptive filter. It converts the switched-capacitor output into a continuous current signal, smoothing transitions and providing a stable input to the filter stage. This intermediary component is essential for achieving clean current output while maintaining circuit modularity.
2Adaptability or versatility
If the switching frequency varies over a wide range, then the voltage regulator can adapt to different loading conditions, but the non-linear relationship between output voltage and switching frequency causes significant variations in VR output voltage and reduces efficiency
Solution Approach 1:
The adaptive multi-stage filter uses feedback mechanisms to monitor the output current and adjust its filtering characteristics dynamically. The filter adapts its response based on the switching frequency and PVT conditions, ensuring linear relationship maintenance across the full frequency range. This feedback control compensates for non-linearities that would otherwise degrade performance.
Solution Approach 2:
The current source circuit employs dynamic components including switched capacitors with variable values and adaptive filter parameters that change with operating conditions. The circuit continuously adapts its characteristics to maintain optimal performance across varying frequencies, transforming a static design into a dynamic system that responds to changing conditions.
3Productivity
If switched capacitors with different types are used, then the circuit can be optimized for specific frequency ranges, but the PVT variations cause significant ripple and non-linear behavior in the current output
Solution Approach 1:
The patent uses switched capacitors of the same type and construction throughout the circuit, ensuring they exhibit identical PVT characteristics. This homogeneity allows the capacitors to vary together in response to temperature and process changes, maintaining consistent current output ratios. The adaptive filter then compensates for the collective PVT variations, achieving both efficiency and reliability.
Solution Approach 2:
The circuit changes the effective capacitance values dynamically by switching between different capacitor configurations and values based on the operating frequency. The adaptive filter also changes its parameters (cut-off frequencies, gain) to match the operating conditions. These parameter adjustments optimize efficiency at different frequencies while the coordinated PVT behavior maintains output consistency.
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 solution achieves reduced variations in VR output voltage across a wide range of frequencies and PVT conditions, ensuring small trim code variations and high yield by minimizing non-linear behavior and filtering noise.
Implementation Method 1
low-pass filtering the voltage and the current at a continuous-time integrator
Implementation Method 2
filtering an output of the continuous-time integrator at an adaptive multi-stage filter
Implementation Method 3
switched-capacitor frequency-to-current converter
Implementation Method 4
a waveform generator, wherein the waveform generator comprises a current mirror having an input path and an output path, the input path is coupled to an output of the adaptive multi-stage filter, the output path comprises a respective capacitor
Data Source
AI summary
Embodiments herein relate to a current source for a waveform generator in a voltage regulator (VR). In one approach, the current source is provided as a switched-capacitor frequency-to-current converter. The current source includes a switching circuit, a continuous-time integrator, and an adaptive multi-stage filter. The switching circuit receives a clock signal which is used to control switches to provide a time-varying voltage and current. The voltage and current are low-pass filtered at the continuous-time integrator before being filtered at the adaptive multi-stage filter. An output current of the adaptive multi-stage filter is then provided as an input current to a waveform generator such as to provide a pulse-width modulation signal for driving a powertrain of the VR. In another aspect, the current source includes a switching circuit and a discrete or digital integrator.