Backlight PWM Signal Processing for Noise Reduction and Circuit Protection
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Solution Overview
Problem
Existing display apparatuses face challenges in preventing damage to the driving circuit and maintaining constant brightness of the backlight module while minimizing audio noise and ensuring efficient operation with pulse width modulating (PWM) signals.
Innovation Solution
A display apparatus with a processing module that adjusts PWM signals to higher frequencies and calculates working cycles, allowing for simultaneous operation of unadjusted and adjusted signals to manage the backlight module's brightness and reduce noise, comprising a receiving module, processing module, selecting module, power circuit, and backlight module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the PWM signal frequency is increased to reduce audio noise, then the audio noise is reduced, but the lighting time of the backlight module is extended which may cause damage to the driving circuit
Solution Approach 1:
The patent applies preliminary action by calculating the working cycle of the PWM signal before actually driving the backlight module. The processing module computes the working cycle in advance and uses this pre-calculated value to control the power circuit, ensuring that the backlight is driven for the optimal duration that prevents both audio noise and over-lighting damage.
Solution Approach 2:
The patent implements feedback by continuously monitoring the PWM signal characteristics and adjusting the working cycle accordingly. The processing module calculates the working cycle based on the actual PWM signal parameters and feeds this information back to the power circuit to dynamically control the backlight driving time, creating a closed-loop control system that prevents both audio noise and over-lighting.
2Stability of the object's composition
If the PWM signal is adjusted to high frequency range to maintain constant brightness, then the brightness stability is improved, but the complexity of the driving module increases
Solution Approach 1:
The patent applies universality by designing the processing module to perform multiple functions: it calculates the working cycle, adjusts the PWM signal frequency, and controls the power circuit all within a single integrated component. This multi-functional approach maintains brightness stability while avoiding the need for separate complex circuits for each function.
Solution Approach 2:
The patent uses parameter changes by dynamically adjusting the PWM signal frequency and working cycle parameters based on real-time conditions. The processing module modifies these parameters to maintain optimal brightness stability without requiring complex hardware changes, achieving stability through software-based parameter optimization.
Data Source
AI summary
A display apparatus includes a receiving module, a processing module, a selecting module, a power circuit, and a backlight module. The receiving module receives a pulse width modulating (PWM) signal from an external component. The processing module processes the PWM signal in a predetermined time duration. The selecting module outputs the unadjusted PWM signal to the power circuit in the predetermined time duration, and outputs an adjusted signal after the predetermined duration. The power circuit generates a first driving current for driving the backlight module to emit lights in response to the unadjusted PWM signal while the processing module processes the PWM signal. The backlight module remains a predetermined brightness after the predetermined time.