Multiphase Voltage Regulator Phase Shedding by PWM Efficiency
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Solution Overview
Problem
In multiphase power supplies, phase shedding to improve efficiency is hindered by variations in phase efficiency due to manufacturing tolerances and degradation over time, leading to lower overall efficiency as less efficient phases are turned off first, causing uneven wear and reduced performance.
Innovation Solution
A mechanism that identifies and disables the least efficient phases by comparing measured pulse widths with a nominal base pulse width, calculated based on input voltage, output voltage, and switching frequency, to reduce energy losses and level wear among phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If phase shedding is performed by turning off phases in numerical order, then power supply efficiency is improved under high load, but manufacturing tolerances and degradation cause uneven wear on phases leading to reduced reliability
Solution Approach 1:
The patent implements feedback by measuring the actual pulse width of each phase and using this information to determine phase efficiency. The system continuously monitors pulse width variations and adjusts phase shedding decisions based on this feedback, ensuring that phases with greater wear or lower efficiency are identified and managed appropriately, thereby maintaining reliability while improving overall efficiency.
Solution Approach 2:
The patent changes the parameter used for phase selection from a fixed numerical order to a dynamic efficiency metric based on measured pulse width. By monitoring pulse width variations and calculating phase efficiency relative to a base pulse width, the system adapts phase shedding decisions to actual phase conditions, resolving the contradiction between efficiency improvement and wear uniformity.
2Loss of energy
If less efficient phases are turned off first to maintain efficiency, then energy losses are reduced, but manufacturing variations cause some phases to be inherently less efficient leading to uneven degradation
Solution Approach 1:
The system measures the actual pulse width of each phase and uses this feedback to identify inherently less efficient phases caused by manufacturing variations. By continuously monitoring pulse width and comparing it to the base pulse width, the system can distinguish between phases that are less efficient due to manufacturing tolerances versus those that have degraded over time, enabling appropriate phase shedding decisions that reduce energy losses while accounting for manufacturing precision limitations.
Solution Approach 2:
The patent introduces a dynamic efficiency parameter based on measured pulse width to compensate for manufacturing precision variations. By calculating phase efficiency as a function of actual versus base pulse width, the system transforms the fixed manufacturing variation problem into a manageable parameter that can be monitored and compensated for through adaptive phase shedding, thereby reducing energy losses despite inherent manufacturing differences.
3Measurement precision
If pulse width measurement is used to identify least efficient phases, then phase efficiency can be accurately determined, but additional measurement and comparison circuitry increases device complexity
Solution Approach 1:
The patent implements self-service by using the existing pulse width modulator switching signals to generate the measurement data needed for phase efficiency determination. The system leverages the PWM signals already present in the power supply circuitry to measure pulse width, eliminating the need for separate external measurement equipment. This approach provides accurate phase efficiency measurement while minimizing additional device complexity by utilizing existing circuit elements.
Data Source
AI summary
A method of operating a multiphase power supply includes identifying a least efficient phase of a plurality of phases in the multiphase power supply based on a comparison of a pulse width for each phase in the plurality of phases, and decreasing an amount of power supplied to a load by the identified least efficient phase.