Voltage Regulator Phase Self-Calibration for Parasitic Impedance
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Solution Overview
Problem
Existing current sensing methods in voltage regulators face significant measurement errors due to varying parasitic impedance in output inductors, leading to inaccurate power management and efficiency issues.
Innovation Solution
A calibration method is implemented where test currents are delivered to each voltage regulator phase, measuring output currents to calculate a gain and offset, establishing a linear relationship between measured and actual currents, thereby accounting for impedance variations and reducing measurement errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If parasitic impedance of output inductor is used for current sensing, then power loss is minimized (using inherent component), but measurement precision deteriorates (large range of variation in parasitic impedance)
Solution Approach 1:
The system performs a calibration operation before normal operation to establish correction factors (gain and offset) for each phase. This preliminary action accounts for variations in parasitic impedance, allowing accurate current measurement without requiring precise knowledge of the impedance values during operation.
Solution Approach 2:
The system changes the operating parameters by applying different test currents (first test current and second test current) during calibration to measure and determine the actual parasitic impedance and correction factors. This allows the system to adapt to the specific characteristics of each phase.
2Measurement precision
If calibration operation is performed for each phase, then measurement precision is improved (accurate gain and offset calculation), but loss of time increases (calibration process duration)
Solution Approach 1:
The calibration operation is performed once during initialization or manufacturing, and the correction factors are stored for reuse. This partial action approach achieves the necessary precision without requiring continuous calibration, thereby minimizing time loss while maintaining accurate measurement throughout the system's operation.
3Manufacturing precision
If test currents are applied during calibration, then manufacturing precision is improved (accurate phase characterization), but use of energy increases (power consumption during calibration)
Solution Approach 1:
The calibration operation using test currents is performed once during manufacturing or initialization, and the results are stored as correction factors. This preliminary energy expenditure enables accurate power management throughout the system's operational life, making the initial energy use worthwhile for achieving precise and efficient operation.
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
This approach enhances the accuracy of current sensing in voltage regulators, improving power management and efficiency by minimizing the impact of parasitic impedance variations.
Implementation Method 1
Current flowing through such an inductor is linearly proportional to a voltage drop across such parasitic impedance. Thus by measuring a voltage across such components, a current associated with a voltage regulator may be obtained.
Data Source
AI summary
A method may include causing a first test current to be delivered for a period of time from a phase of a voltage regulator to a load coupled to the voltage regulator, the phase configured to deliver electrical energy to the load. The method may also include measuring a first measured output current associated with the first test current. The method may further include causing a second test current to be delivered from the phase to the load for the period of time, the second test current differing from the first test current by a known offset. The method may additionally include measuring a second measured output current associated with the second test current. The method may also include calculating the respective gain and the respective offset of the phase based on the first measured output current, the second measured output current, the period of time, and the known offset.