Switching Power Supply Jitter Control for EMI and Conduction Loss
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Solution Overview
Problem
Frequency jittering control in switching power supplies can lead to higher conduction loss, lower system efficiency, and additional electromagnetic radiation, failing to optimally suppress electromagnetic interference (EMI) across varying loads.
Innovation Solution
A new frequency jittering control method that generates two frequency jittering signals to adjust the operating frequency range and peak inductor current amplitude, with opposite change tendencies to maintain output power stability, incorporating a frequency jittering control circuit with superimposing circuits to adjust switching control signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If frequency jittering control is applied to suppress EMI, then electromagnetic interference suppression is improved, but conduction loss increases and system efficiency decreases
Solution Approach 1:
The patent implements dynamic adjustment of the frequency jittering range based on load conditions. The controller dynamically modifies the frequency deviation magnitude according to the actual load, using smaller jittering ranges at light loads to reduce conduction loss while maintaining EMI suppression effectiveness at heavy loads where larger ranges are beneficial.
Solution Approach 2:
The patent changes the operating parameters by adjusting the frequency jittering range as a variable parameter rather than using a fixed range. This allows optimization of the trade-off between EMI suppression and conduction loss by adapting the frequency deviation magnitude to match the load conditions, thereby improving overall system efficiency.
2Object-affected harmful factors
If frequency jittering control is applied to suppress EMI, then electromagnetic interference suppression is improved, but system efficiency decreases
Solution Approach 1:
The controller dynamically adapts the frequency jittering range to load conditions, using minimal jittering at light loads to maintain efficiency while providing adequate EMI suppression, and increasing jittering range at heavy loads where EMI suppression requirements are more stringent.
Solution Approach 2:
The system optimizes efficiency by treating the frequency jittering range as a controllable parameter that varies with load, thereby improving productivity through efficient energy utilization while maintaining effective EMI suppression across different operating conditions.
3Object-generated harmful factors
If frequency jittering control is applied to suppress EMI, then electromagnetic radiation suppression is improved, but conduction loss increases
Solution Approach 1:
The patent employs dynamic control where the frequency jittering range is adjusted in real-time based on load detection. At light loads, the jittering range is reduced to minimize conduction loss while still providing necessary electromagnetic radiation suppression, and expanded at heavy loads where radiation suppression becomes more critical.
Solution Approach 2:
The system optimizes the balance between radiation suppression and energy loss by varying the frequency jittering parameter according to load conditions, achieving effective electromagnetic radiation suppression with minimal conduction loss through adaptive parameter adjustment.
4Object-generated harmful factors
If frequency jittering control is applied to suppress EMI, then electromagnetic radiation suppression is improved, but system efficiency decreases
Solution Approach 1:
The controller dynamically adjusts the frequency jittering range to match load requirements, maintaining high system efficiency by using minimal jittering at light loads while ensuring adequate electromagnetic radiation suppression, and increasing jittering effectiveness at heavy loads where radiation suppression is more demanding.
Solution Approach 2:
The system improves productivity by optimizing the frequency jittering parameter dynamically, achieving effective electromagnetic radiation suppression across all load conditions while minimizing the negative impact on system efficiency through intelligent parameter adaptation.
Data Source
AI summary
A controller of a switching power supply can include: a frequency-jittering control circuit configured to generate a first frequency-jittering signal and a second frequency-jittering signal; where a jittering range of an operating frequency of a power transistor in the switching power supply is adjusted by the first frequency-jittering signal; and where a jittering amplitude of a peak value of an inductor current of the switching power supply is adjusted by the second frequency-jittering signal.