Power Supply Controller Acoustic Noise Reduction via Slope Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power supply controllers that aim to reduce acoustic noise from multi-layer ceramic capacitors (MLCCs) in electronic devices either increase power consumption, shortening battery endurance, or fail to eliminate noise due to rapid voltage variations, even when frequencies are outside audible ranges.
Innovation Solution
A power supply controller that generates a control signal using a voltage identification (VID) signal and a voltage sensing signal to adjust the output voltage, employing a slope control circuit to limit the descending slope of the output voltage, ensuring it decreases at a velocity not exceeding a predetermined rate, thereby reducing acoustic noise while maintaining efficient power management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the output voltage is maintained at a constant high voltage level to avoid acoustic noise, then acoustic noise is eliminated, but power consumption increases and battery endurance time is shortened
Solution Approach 1:
The patent applies dynamics by transitioning from a static constant voltage approach to a dynamic voltage adjustment approach. The controller dynamically adjusts the output voltage based on load requirements, allowing the voltage to vary within controlled boundaries rather than maintaining a fixed high level, thereby reducing power consumption while managing acoustic noise through controlled variation rates
Solution Approach 2:
The patent changes the parameter of voltage variation rate (dv/dt) to resolve the contradiction. By controlling the rate of voltage change to be below a threshold value, the system allows voltage to vary according to load needs (reducing power consumption) while preventing rapid changes that would generate acoustic noise in the MLCC
2Object-affected harmful factors
If the voltage variation frequency is kept below the audible range to avoid acoustic noise, then acoustic noise is reduced, but rapid voltage variations can still generate pulse waves with multiple frequencies that cause MLCC oscillation and acoustic noise
Solution Approach 1:
The patent applies preliminary anti-action by proactively limiting the voltage variation rate before rapid changes can occur. The controller preemptively constrains dv/dt to remain below the threshold that would generate audible frequencies or cause MLCC oscillation, preventing the harmful effect before it can manifest even when load conditions demand faster voltage changes
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 effectively reduces acoustic noise in electronic devices while prolonging battery endurance by dynamically adjusting the output voltage, ensuring it decreases at a controlled rate, thus minimizing power consumption and extending device usage.
Implementation Method 1
MLCC is formed by stacking electrode layers and ceramic materials, wherein the ceramic material is a piezoelectric material. When an AC voltage is applied on two ends of a MLCC, the MLCC will be deformed and the deformed MLCC will impact the circuit board nearby the deformed MLCC with a frequency.
Data Source
AI summary
The power supply controller is for use in a power supply circuit, for reducing acoustic noise. The power supply control circuit generates a control signal according to a voltage identification (VID) signal and a voltage sense signal, to operate a power switch in a power stage circuit, thus converting an input voltage to an output voltage. The power supply control circuit includes a conversion circuit and a PWM control circuit. The conversion circuit includes a DAC and a slope control circuit. When the power supply controller operates in an acoustic noise reduction mode and when a present level is higher than a requested level, the slope control circuit adjusts a descending slope of an analog voltage identification signal which is generated according to the VID signal, so as to restrain a decrease velocity of the output voltage to be higher than zero but not higher than a predetermined velocity.