Sensorless Load Current Extraction in DC-DC Converters
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing switch mode power converters (SMPCs) face challenges in accurately determining instantaneous average load current without physical sensing, leading to slow response times and increased power consumption due to direct measurement methods, which are not suitable for integrated circuits.
Innovation Solution
The implementation of an average load current calculator circuit within the SMPC control circuit, utilizing a peak/valley detector and current error corrector to calculate and generate instantaneous average load current using input and output voltage data, inductance values, and ripple current calculations, allowing for sensorless extraction of load current data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct measurement methods are used to determine load current, then measurement precision is improved, but power consumption increases and device complexity increases
Solution Approach 1:
The patent uses an intermediary approach by measuring the voltage across the inductor and using mathematical relationships (V=L*dI/dt) to derive the current information, rather than directly measuring current. This intermediary voltage measurement combined with mathematical processing achieves accurate current determination while avoiding the power consumption and complexity of direct current sensing circuits.
Solution Approach 2:
The patent replaces physical current sensing mechanisms with a mathematical/model-based approach. By substituting direct electrical measurement with mathematical relationships involving inductor voltage and current equations, the system achieves the same measurement function with reduced power consumption and circuit complexity.
2Measurement precision
If direct measurement methods are used to determine load current, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent uses an intermediary approach by measuring the voltage across the inductor and using mathematical relationships (V=L*dI/dt) to derive the current information, rather than directly measuring current. This intermediary voltage measurement combined with mathematical processing achieves accurate current determination while avoiding the power consumption and complexity of direct current sensing circuits.
Solution Approach 2:
The patent replaces physical current sensing mechanisms with a mathematical/model-based approach. By substituting direct electrical measurement with mathematical relationships involving inductor voltage and current equations, the system achieves the same measurement function with reduced power consumption and circuit complexity.
3Device complexity
If sensorless extraction methods are used, then device complexity is reduced and power consumption is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent incorporates feedback mechanisms where the derived current information is continuously monitored and used to adjust control parameters. The system uses the relationship between inductor voltage, switching duty cycle, and load current with feedback loops that compare expected versus actual behavior, thereby maintaining measurement precision while using sensorless extraction methods.
Solution Approach 2:
The patent changes the measurement parameter from direct current sensing to voltage sensing across the inductor, and changes the processing method from direct measurement to mathematical derivation. By transforming the measurement approach and using parameters like switching frequency, duty cycle, and inductor voltage, the system achieves accurate current extraction without complex sensing circuits.
4Measurement precision
If conventional current sensing is used, then measurement precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent replaces physical current sensing mechanisms with a mathematical/model-based approach. By substituting direct electrical measurement with mathematical relationships involving inductor voltage and current equations, the system achieves the same measurement function with reduced power consumption and circuit complexity, making it more suitable for integrated circuit implementation.
Solution Approach 2:
The patent uses an intermediary approach by measuring the voltage across the inductor and using mathematical relationships (V=L*dI/dt) to derive the current information, rather than directly measuring current. This intermediary voltage measurement combined with mathematical processing achieves accurate current determination while avoiding the power consumption and complexity of direct current sensing circuits.
Data Source
AI summary
An average load current calculator circuit configured for determining an average load current within an at least one phase switch mode power converter (SMPC) having at least one peak/valley detector receives an inductor current sense signal and determines and holds a peak or valley amplitude of the inductor current sense signal. A current corrector circuit receives an input voltage and an output voltage of the SMPC and an inductance value of the inductor of the SMPC for determining an average correction current of the peak or valley amplitude of the current sense. An average current generator receives the peak or valley amplitude of the current sense signal and the average correction current for determining the instantaneous average load current within a switch mode power converter (SMPC) by additively combining the peak or valley amplitude of the current sense signal and the average correction current.