Switching Control Circuit Dead Time Optimization
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Solution Overview
Problem
Digital switching power supply circuits with PWM control face challenges in optimizing dead time to enhance conversion efficiency, as existing methods rely on duty-cycle measurements which are prone to noise and instability.
Innovation Solution
A power supply circuit with a switching control section that calculates a current control value and optimizes dead times (td1 and td2) based on the comparison between output voltage and a target value, using a dead time compensation circuit to adjust PWM signals without requiring duty-cycle measurements, thereby stabilizing current control and improving conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If duty-cycle control value is used for dead time optimization, then conversion efficiency can be improved, but the control becomes unstable due to noise in duty-cycle measurements
Solution Approach 1:
The patent introduces a current control value as an intermediary parameter to replace direct duty-cycle measurements for dead time optimization. The current control value serves as a mediator that reflects the actual current state without being susceptible to noise, thereby enabling stable dead time control while maintaining conversion efficiency improvements
Solution Approach 2:
The patent replaces the measurement-based duty-cycle control mechanism with a current-controlled mechanism. Instead of relying on mechanical/electrical measurements of duty cycle that are prone to noise, the system uses current control values that are inherently more stable and less susceptible to measurement errors
2Loss of energy
If dead time is optimized for maximum conversion efficiency, then energy loss is reduced, but the system becomes sensitive to current waveform noise
Solution Approach 1:
The patent employs a simple dead time compensation circuit that uses basic computational operations rather than complex noise filtering hardware. This approach achieves effective dead time optimization without introducing sensitive measurement systems, thereby avoiding the problem of noise sensitivity while maintaining energy efficiency
3Loss of energy
If autonomous dead time control is implemented, then conversion efficiency is enhanced, but the device complexity increases
Solution Approach 1:
The patent implements autonomous dead time control where the switching control section automatically adjusts dead time based on current control values without requiring external intervention or complex control algorithms. The system serves itself by using internally generated current control values to optimize dead time, achieving efficiency improvement without proportionally increasing complexity
Solution Approach 2:
The patent optimizes dead time by changing the control parameter from duty-cycle measurements to current control values. This parameter substitution allows for automated control using simple computational operations, enhancing conversion efficiency while avoiding the need for complex control circuitry
Data Source
AI summary
According to one embodiment, switching control section calculates a current control value based on a comparison result between a smoothed voltage of an output of a switching circuit and a target value, and controls a dead time of the switching circuit based on the current control value.