Insulated Switching Power Supply Control for Load Regulation and EMI
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Solution Overview
Problem
Conventional insulated switching power supplies face challenges in load regulation and Electromagnetic Interference (EMI) characteristics, particularly in vehicle applications.
Innovation Solution
A power supply controller with a monitor voltage generation part, sample/hold part, and controller that uses fixed on-time control and frequency jitter to improve load regulation and EMI characteristics, incorporating a transformer and rectifying/smoothing circuit for stable output voltage and reduced electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional insulated switching power supplies are used, then the basic power conversion function is achieved, but load regulation is insufficient
Solution Approach 1:
The patent applies dynamics by making the sampling timing adaptive rather than fixed. The sampling timing is dynamically adjusted based on the primary current waveform characteristics, allowing the system to optimize feedback sampling for different operating conditions and improve load regulation while maintaining output stability.
Solution Approach 2:
The patent changes the parameter of sampling timing based on the primary current waveform. By detecting waveform characteristics and adjusting when feedback is sampled, the system optimizes the feedback signal quality across different load conditions, thereby improving load regulation and output stability simultaneously.
2Object-affected harmful factors
If conventional insulated switching power supplies are used, then the basic power conversion function is achieved, but EMI characteristics are insufficient
Solution Approach 1:
The patent applies periodic action through frequency jitter, where the switching frequency is deliberately modulated with a periodic variation pattern. This spreads the EMI energy across a broader frequency spectrum rather than concentrating it at a single frequency, reducing peak EMI emissions and improving electromagnetic compatibility while maintaining reliable operation.
Solution Approach 2:
The patent makes the switching frequency dynamic by applying frequency jitter. The frequency varies periodically around a nominal value, which prevents EMI energy from concentrating at a single frequency point, thereby reducing harmful electromagnetic emissions while maintaining system reliability through controlled variation.
3Device complexity
If fixed on-time control is used, then simple control is achieved, but load regulation needs improvement
Solution Approach 1:
The patent enhances the simple fixed on-time control by incorporating adaptive feedback sampling. The system samples the primary voltage at optimally determined timings based on primary current waveform detection, creating an intelligent feedback mechanism that improves load regulation while building upon the simple fixed on-time control foundation rather than replacing it entirely.
Solution Approach 2:
The patent applies preliminary action by detecting primary current waveform characteristics before determining the optimal sampling timing for feedback. This preliminary detection allows the system to pre-establish the best sampling point based on waveform features, improving load regulation through informed feedback sampling while maintaining the simplicity of fixed on-time control for the main switching operation.
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
The solution provides enhanced load regulation and improved EMI characteristics, ensuring stable output voltage and reducing electromagnetic interference in vehicle applications.
Implementation Method 1
a transformer configured to apply a DC input voltage to a primary winding; and a rectifying/smoothing circuit configured to generate a DC output voltage by rectifying/smoothing an induced voltage appearing in a secondary winding of the transformer
Data Source
AI summary
There is provided a power supply controller including: a monitor voltage generation part configured to generate a monitor voltage according to a primary voltage of a transformer that forms an insulated switching power supply; a sample/hold part configured to sample/hold the monitor voltage and output a feedback voltage; and a controller configured to turn on/off a primary current of the transformer by a fixed on-time method according to the feedback voltage, wherein the sample/hold part samples/holds the primary voltage at a plurality of different timings and outputs one of a plurality of hold values as the feedback voltage.