Multi-Phase VR Calibration Using IPstage RDS(on) Sensing
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Solution Overview
Problem
Current multi-phase voltage regulator systems face challenges in achieving accurate current sense due to parameter mismatch and layout issues, leading to increased costs and complexity in accommodating different MOSFET suppliers and noisy environments, which hinders the ability to meet stringent accuracy targets set by CPU manufacturers.
Innovation Solution
The implementation of a digital VR controller that recognizes and selects optimized IPstage configuration files for different types of smart IPstages, allowing for two-stage calibration during the development phase, which includes initial calibration using automatic test equipment and fine-tuning during system development, enabling the use of multiple IPstage types from various vendors and reducing the need for production-level calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If inductor DCR sense is used for current measurement, then the system can operate with conventional circuitry, but current sense accuracy cannot meet the stringent targets (+/-3% for 30-100% maximum load) required by CPU manufacturers
Solution Approach 1:
The patent transitions from indirect current sensing via inductor DCR to direct current sensing through the MOSFET's RDS(on) parameter. By measuring the voltage drop across the MOSFET's on-resistance during its on-state, the system achieves +/-3% or better current sense accuracy while maintaining ease of manufacture through integration in the IPstage.
Solution Approach 2:
The patent replaces the passive inductor-based sensing mechanism with an active MOSFET-based sensing mechanism. The MOSFET's inherent RDS(on) characteristic is exploited as a sensing element, substituting the need for separate inductor DCR measurement circuitry and providing superior accuracy through the MOSFET's controlled resistance state.
2Adaptability or versatility
If multiple MOSFET suppliers are accommodated, then supply chain flexibility increases, but parameter mismatch and tolerance accumulation worsen current sense accuracy
Solution Approach 1:
Each IPstage from different MOSFET suppliers performs self-calibration by measuring its own actual RDS(on) characteristics during operation. The system automatically determines calibration parameters specific to each IPstage's MOSFET implementation, eliminating the need for manual characterization and accommodating supplier variations without impacting accuracy.
Solution Approach 2:
The patent implements calibration procedures during the development and production phases to pre-determine accurate RDS(on) parameters for each IPstage type. By performing this calibration in advance, the system establishes precise current sense parameters before deployment, ensuring accuracy is maintained across multiple suppliers without requiring real-time adjustments.
3Measurement precision
If production-level calibration is implemented, then current sense accuracy improves, but manufacturing cost and complexity increase significantly
Solution Approach 1:
The IPstage performs self-calibration using its own operational characteristics and integrated measurement circuitry. By leveraging the MOSFET's inherent properties and built-in sensing capabilities, the system automatically determines its calibration parameters without requiring external test equipment or manual intervention, thereby improving accuracy while minimizing added complexity.
Solution Approach 2:
The patent combines the current sensing function and calibration function within the same integrated IPstage circuitry. The MOSFET serves dual purposes as both a power switch and a sensing element, while the same circuitry used for power operation is also used for measurement and calibration, eliminating the need for separate calibration hardware and reducing overall system complexity.
Data Source
AI summary
Methods and systems are disclosed that may be employed to enable multi-phase voltage regulator (VR) system calibration during the development phase of a multi-phase VR system so as to meet defined accuracy targets and, in one example, to avoid the need for system level calibration in a production environment. The disclosed systems and methods may be further implemented to enable use of multiple sources for and types of integrated power stages (IPstages) in a common multi-phase VR system configuration while still achieving the required current sense accuracy, thus reducing or substantially eliminating continuity of supply (COS) concerns.