LED Drive Control for Abnormal Sound Suppression
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Solution Overview
Problem
Existing technologies for suppressing abnormal sounds in direct view LED displays are costly due to complex configurations and the use of numerous components, and they may compromise product quality with the risk of tantalum capacitor failures.
Innovation Solution
A drive control device and method that control the light emission of LEDs in an LED array by making the period during which the LEDs are off shorter than the time indicated by an input signal, thereby reducing the ripple voltage and suppressing abnormal sounds at a lower cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If low-distortion MLCCs or solid capacitors are used to suppress noise, then abnormal sound is reduced, but manufacturing cost increases
Solution Approach 1:
The patent changes the drive waveform parameters of the LED display, specifically optimizing the PWM duty cycle and current modulation characteristics to reduce ripple voltage amplitude and frequency content that excites MLCC vibrations, thereby suppressing abnormal sounds without requiring expensive low-distortion capacitors
2Object-affected harmful factors
If multiple bypass capacitors are added to generate opposite phase vibrations, then vibration sound is suppressed, but device complexity doubles
Solution Approach 1:
The patent extracts and eliminates the root cause of abnormal sounds by optimizing the LED drive waveform to minimize ripple voltage, rather than adding complex vibration cancellation mechanisms with multiple capacitors and phase control circuits
Solution Approach 2:
The patent replaces the mechanical vibration cancellation approach (multiple capacitors generating opposite phase vibrations) with an electrical control approach (optimized PWM drive waveform) that prevents ripple voltage from exciting capacitor vibrations in the first place
3Object-affected harmful factors
If tantalum capacitors are used to replace MLCCs, then noise is suppressed, but product reliability decreases due to short mode failures
Solution Approach 1:
The patent converts the potential harm of using standard MLCCs (which can generate abnormal sounds) into a benefit by optimizing the drive waveform to minimize ripple voltage, ensuring that even standard capacitors do not produce noticeable sounds while maintaining their high reliability characteristics
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 suppresses the generation of abnormal sounds in direct view LED displays at a lower cost by reducing the ripple voltage and minimizing the risk of product quality issues associated with tantalum capacitors.
Implementation Method 1
a light emission control unit configured to control light emission of light emitting diodes (LEDs) constituting an LED array
Data Source
AI summary
The present disclosure relates to a drive control device, a drive control method, an information processing system, and an information processing method for an information processing system capable of suppressing generation of an abnormal sound in a passive-matrix driven LED display device. A blanking interval between frames is made shorter than a time set according to a display standard, and the blanking interval ends before a ripple voltage rises. Accordingly, suppressing a rise in the ripple voltage caused by a reduction in current flow through LEDs during the blanking interval lowers a voltage applied to an MLCC, and suppressing distortion of a substrate resulting from expansion or contraction of the MLCC caused by the voltage application suppresses generation of an abnormal sound. This disclosure is applicable to a passive-matrix driven LED display device.