Backlight Driving Circuit Noise Reduction via Time-Delay Control
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Solution Overview
Problem
Large-sized and high-brightness display devices using direct-type backlight modules face noise issues due to resonating magnetic coils in inductance components, which affect performance, despite efforts to improve materials and manufacturing processes.
Innovation Solution
A backlight driving circuit that includes a pulse width modulator, time-delay sub-circuits, and a driving sub-circuit, where the time-delay sub-circuits delay control signals to prevent synchronized operation of inductance and switching components, thereby avoiding resonance and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If inductance components and switching components operate synchronously to control backlight brightness, then the backlight driving efficiency is improved, but magnetic coil resonance occurs causing excessive noise
Solution Approach 1:
The patent applies periodic action by using pulse width modulation (PWM) to control the backlight driving circuit. The controlling signal comprises periodic pulses with different widths, where the duty cycle of the pulses determines the brightness level. This periodic control method allows the inductance and switching components to operate in a controlled manner that prevents synchronous resonance while maintaining driving efficiency.
Solution Approach 2:
The patent implements dynamics by making the inductance component and switching component operate at different time points within each PWM cycle. The controlling signal is designed so that when one component is activated, the other is in a different state, preventing simultaneous operation that would cause resonance. This dynamic timing separation maintains overall system efficiency while eliminating noise.
2Object-generated harmful factors
If materials and manufacturing processes are improved to reduce noise, then the noise level decreases, but the complexity and cost of production increase
Solution Approach 1:
The patent replaces physical/material-based noise reduction approaches with an electrical control-based solution. Instead of improving materials or manufacturing processes to reduce resonance, the invention uses PWM control signals to dynamically manage the operation timing of inductance and switching components. This substitution of control methodology achieves noise reduction without increasing material complexity or production difficulty.
Data Source
AI summary
A backlight driving circuit includes a pulse width modulator, at least one time-delay sub-circuit and a driving sub-circuit. The pulse width modulator is configured to transmit a control signal including a plurality of pulses. The at least one time-delay sub-circuit is configured to delay at least one pulse of the control signal from the pulse width modulator that is transmitted to the at least one time-delay sub-circuit by a set time. The driving sub-circuit is coupled to the at least one time-delay sub-circuit, and the driving sub-circuit is configured to drive at least one of a plurality of light-emitting devices in a backlight module to be turned on or off according to a control signal from the at least one time-delay sub-circuit obtained after the at least one pulse is delayed.