Feedback Impedance Modulation in Power Converters for Light-Load Saving
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Solution Overview
Problem
Conventional power converters experience high power consumption due to constant feedback resistor resistance across all load conditions, leading to inefficiencies at no-load and light-load conditions.
Innovation Solution
A feedback circuit with impedance modulation using a compare circuit, counter, and switching resistor circuit that adjusts feedback impedance based on load conditions, reducing resistance at no-load and light-load and increasing it at full-load, thereby reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a constant feedback resistor resistance is used in conventional power converters, then the feedback loop remains simple and stable, but power consumption increases significantly at no-load and light-load conditions
Solution Approach 1:
The feedback resistor resistance is made dynamic rather than constant. The switching resistor circuit adjusts the feedback impedance based on load conditions, switching between different resistance values to optimize power consumption across different operating scenarios while maintaining feedback loop functionality.
Solution Approach 2:
The feedback resistor is segmented into multiple resistive elements that can be independently switched. This allows the feedback circuit to select appropriate resistance segments based on load conditions, reducing power consumption at light-load while maintaining stability at full-load without requiring a completely complex redesign.
2Loss of energy
If the feedback resistor resistance is increased at no-load and light-load conditions, then power saving is improved, but the feedback loop stability may be affected
Solution Approach 1:
The system uses feedback from the load condition detection to dynamically adjust the feedback resistor resistance. The compare circuit monitors the feedback signal and controls the counter and switching resistor circuit to maintain optimal resistance values that preserve feedback loop stability while maximizing power savings under varying load conditions.
Solution Approach 2:
The feedback resistor resistance parameter is changed dynamically based on operating conditions. By adjusting this key parameter according to load requirements, the system achieves power savings at light-load while maintaining the stability needed for reliable operation at all load levels.
3Use of energy by moving object
If feedback impedance is dynamically modulated to reduce power consumption, then energy efficiency is enhanced, but the control circuit complexity increases
Solution Approach 1:
The system performs preliminary detection of load conditions through the feedback signal and proactively adjusts the feedback impedance before significant power consumption issues arise. This preliminary action allows smooth transitions between different resistance states, enhancing energy efficiency while keeping control complexity manageable through predictive rather than reactive control.
Data Source
AI summary
A feedback circuit with feedback impedance modulation according to the present invention comprises a compare circuit, a counter and a switching resistor circuit. The compare circuit receives a feedback signal of a power converter to compare the feedback signal with a threshold signal for generating a control signal. The feedback signal is correlated to a load condition of the power converter. The counter is coupled to the compare circuit and generates a modulation signal in response to the control signal. The switching resistor circuit is coupled to the counter and a feedback loop of the power converter for modulating a feedback impedance of the power converter in response to the modulation signal. The feedback impedance is directly modulated from a lower resistance to a higher resistance when the load condition is reduced from a half/full-load to a no/light-load. The feedback impedance is gradually modulated from a higher resistance to a lower resistance when the load condition is increased from the no/light-load to the half/full-load.