Switching Regulator Compensation Signal Noise Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Switching regulators experience noise distortion in compensation signals around valleys, which negatively impact power factor and total harmonic distortion, especially when input voltage is lower than output voltage or in applications with tri-electrode AC switches or frequency modulation.
Innovation Solution
A control circuit with a compensation circuit that adjusts the compensation signal based on input voltage levels, using a level detection circuit, conduction control circuit, and voltage source circuit to maintain a stable compensation signal when input voltage is equal to or lower than a predetermined level, thereby reducing noise and resetting the signal periodically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the compensation signal is generated by the error amplifier circuit comparing the feedback signal with the reference signal, then the output voltage is regulated accurately, but noises appear around valleys of the compensation signal when input voltage is not higher than output voltage
Solution Approach 1:
The compensation signal is reset to a predetermined voltage level before the valleys occur by detecting when the input voltage is not higher than the output voltage. This preliminary reset action prevents the noise distortion from occurring in the first place, rather than attempting to correct it after it appears.
Solution Approach 2:
The invention converts the harmful noise distortion around valleys into a beneficial controlled reset mechanism. By intentionally resetting the compensation signal at the valleys, the circuit eliminates the noise problem while maintaining accurate output voltage regulation, turning a problematic condition into a useful control opportunity.
2Productivity
If the compensation signal is periodically reset to limit operation frequency in frequency modulated switching regulators, then the frequency is controlled within proper range, but noises appear around valleys of the compensation signal
Solution Approach 1:
The compensation signal is reset to a predetermined voltage level before the valleys occur by detecting when the input voltage is not higher than the output voltage. This preliminary reset action prevents the noise distortion from occurring in the first place, rather than attempting to correct it after it appears.
3Ease of operation
If a tri-electrode AC switch (TRIAC) is used to drive LED circuit, then the switching regulation is achieved, but the trigger action enhances the noises around valleys of the compensation signal
Solution Approach 1:
The compensation signal is reset to a predetermined voltage level before the valleys occur by detecting when the input voltage is not higher than the output voltage. This preliminary reset action prevents the noise distortion from occurring in the first place, rather than attempting to correct it after it appears.
Data Source
AI summary
The present invention discloses a switching regulator and a control circuit and a control method thereof. The switching regulator generates a compensation signal according to a feedback signal, and generates a driving signal according to the compensation signal, to control a power stage for converting an input voltage to an output voltage. The compensation signal is adjusted according to the input voltage, such that when the input voltage is equal to or lower than a predetermined level, the compensation signal is kept at a predetermined value.