Power Converter Controller Eliminating Acoustic Noise
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Solution Overview
Problem
Existing controllers for power converters generate annoying acoustic noise when the frequency of the gate control signal falls within the human auditory range, and prior solutions for noise reduction compromise power saving, circuit complexity, and output voltage stability.
Innovation Solution
A controller with a feedback pin, current detection pin, burst mode signal generation module, and gate signal generation unit that adjusts the frequency of the gate control signal by modifying the resistance of a compensation resistor based on the detected frequency, ensuring the signal falls outside the human auditory range to eliminate noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the gate control signal frequency is adjusted to eliminate acoustic noise, then acoustic noise is reduced, but circuit complexity increases
Solution Approach 1:
The patent employs a feedback mechanism where the controller monitors the frequency of the gate control signal and automatically adjusts the compensation resistor value to maintain the frequency outside the human auditory range. This closed-loop control eliminates acoustic noise without requiring complex external circuitry, as the adjustment is performed internally by the controller based on real-time frequency detection.
Solution Approach 2:
The patent changes the resistance value of the compensation resistor dynamically based on the detected frequency of the gate control signal. By adjusting this single parameter (resistance), the controller can shift the operating frequency away from the human auditory range (20Hz-20kHz), thereby eliminating acoustic noise while keeping the overall circuit structure simple.
2Use of energy by moving object
If burst mode is used for light load operation, then power consumption is reduced, but acoustic noise is generated
Solution Approach 1:
The patent dynamically adjusts the compensation resistor value to change the frequency of the gate control signal during burst mode operation. By shifting the frequency outside the human auditory range, the patent maintains the power-saving benefits of burst mode while eliminating the associated acoustic noise, thus resolving the contradiction between energy efficiency and noise reduction.
Solution Approach 2:
The controller continuously monitors the gate control signal frequency and provides feedback to adjust the compensation resistor accordingly. This ensures that even during burst mode operation at light loads, the frequency remains outside the human auditory range, preventing acoustic noise while maintaining reduced power consumption.
Data Source
AI summary
A controller for eliminating acoustic noise of a power converter includes a control unit and a gate signal generation unit. The control unit is used for detecting a frequency corresponding to a gate control signal in a burst mode of the power converter. When the frequency is greater than a predetermined frequency, the control unit increases a resistance of a compensation resistor coupled to a compensation pin of the power converter; and when the frequency is less than the predetermined frequency, the control unit decreases the resistance of the compensation resistor. The gate signal generation unit is coupled to the control unit for generating the gate control signal to a power switch of a primary side of the power converter according to the resistance of the compensation resistor. The power switch is turned on according to the gate control signal.