DC-DC Converter Load Current Sensing via Digital Filtering
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Solution Overview
Problem
Determining load current in DC-DC switching converters is complex and often requires complex analog circuitry that draws excessive power, making it inefficient for thermal management and other operational adjustments.
Innovation Solution
A DC-DC converter design incorporating high side and low side switches, output inductors, capacitors, comparators, and logic circuitry to generate PWM signals and determine average voltage values, allowing for load current indication without drawing excessive power, and implementing alarm signals for overcurrent and undervoltage conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex analog circuitry is used to determine load current, then measurement precision is improved, but use of energy worsens due to excessive power consumption
Solution Approach 1:
The patent replaces complex analog circuitry with digital signal processing methods. Specifically, it uses digital filtering (moving average filter) and digital signal analysis to determine load current from PWM controller output signals, eliminating the need for power-hungry analog current sensing circuits while maintaining measurement accuracy.
Solution Approach 2:
The patent creates a digital replica of the load current information by analyzing the PWM controller's output signals. Instead of directly measuring current with analog sensors, it processes copies of voltage signals that correlate with current conditions through digital algorithms, reducing power consumption while preserving measurement capability.
2Measurement precision
If complex analog circuitry is used to determine load current, then measurement precision is improved, but device complexity worsens
Solution Approach 1:
The patent substitutes analog circuit components with digital signal processing operations implemented in software or digital logic. This reduces circuit complexity by eliminating physical analog sensors, filters, and signal conditioners, replacing them with programmable digital algorithms that achieve the same measurement function with fewer physical components.
Solution Approach 2:
The patent makes the PWM controller's digital signal processing capabilities perform multiple functions: generating control signals, filtering noise, analyzing load conditions, and determining current levels. This multi-functionality eliminates the need for separate dedicated current sensing circuits, reducing overall device complexity while maintaining measurement precision.
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
Enables efficient load current determination and thermal management by reducing power consumption and improving operational control, preventing excessive thermal loading and short circuits through precise voltage regulation.
Implementation Method 1
an output capacitor coupled to the second end of the output inductor
Implementation Method 2
a second end of the output inductor providing a regulated output for a load
Data Source
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AI summary
A DC-DC converter including digital circuitry for determining load current supplied to a load. In some embodiments the digital circuitry determines the load current differently based on whether the DC-DC converter is operating in pulse frequency modulation mode or pulse width modulation mode. In some embodiments the DC-DC converter includes circuitry for determining if a short circuit or over current condition exists.