DC-DC Converter Inductor Detection Efficiency
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Solution Overview
Problem
Integrated DC-DC converters face efficiency losses when using external inductors larger than the smallest value optimized for, as the minimum ON time is determined for a specific inductor value, leading to reduced efficiency at higher inductor values.
Innovation Solution
A DC-DC converter with an inductor current detector and back-gate current detector adjusts the minimum ON time of the high-side power transistor based on the actual inductance value, using control logic and timers to extend the ON time for larger inductors, ensuring efficiency is maintained across various inductor values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the minimum ON time is optimized for a small inductor value, then the converter efficiency is optimized for that specific inductor value, but the converter efficiency deteriorates when bigger inductor values are used
Solution Approach 1:
The patent implements dynamic adjustment of the minimum ON time parameter based on detected inductor values. The system transitions from a static, fixed minimum ON time optimized for a specific inductor to a dynamic parameter that automatically adapts to different inductor values through detection and adjustment mechanisms, thereby maintaining optimal converter efficiency across various inductor configurations
Solution Approach 2:
The patent changes the minimum ON time parameter based on the detected inductor value. By detecting whether a small or big inductor is connected and accordingly adjusting the minimum ON time parameter, the system optimizes converter efficiency for each inductor type, resolving the contradiction between efficiency optimization for a specific inductor value and adaptability to different inductor values
2Loss of energy
If the minimum ON time is extended for bigger inductors, then the converter efficiency improves, but the switching frequency decreases
Solution Approach 1:
The patent selectively changes the minimum ON time parameter based on the detected inductor value. For small inductors, the original minimum ON time is maintained to preserve switching frequency. For big inductors, the minimum ON time is extended to improve efficiency. This conditional parameter adjustment resolves the contradiction by applying parameter changes only when necessary
3Stability of the object's composition
If the minimum ON time is increased to maintain efficiency with larger inductors, then the output voltage ripple decreases, but the response time to load changes increases
Solution Approach 1:
The patent implements conditional parameter changes to the minimum ON time based on inductor detection. For small inductors, the original minimum ON time is preserved, maintaining fast response time. For big inductors, the minimum ON time is extended to reduce output voltage ripple. This selective adjustment resolves the contradiction between stability and response time by adapting the parameter to the specific inductor configuration
Data Source
AI summary
A DC-DC converter has high-side power and low-side power transistors connected in series between supply terminals, an inductor connected between the power transistors and an output terminal. A comparator compares the output voltage with a reference voltage. A detector detects when inductor current approaches zero. A timer is configured to determine a minimum ON time of the high-side power transistor optimized for a particular value inductor. A current detector detects current flow in the back-gate diode of the low-side power transistor. timer is configured to determine an overriding ON time in response to the back-gate current detector. Logic provides control signals to gate power transistors in response to the comparator and the longer one of the minimum ON time and the overriding ON time. The minimum ON time for the high-side power transistor is adjusted in response to the actual inductance of the inductor.