LED Drive Circuit Noise Immunity via Dynamic Reference Voltage
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Solution Overview
Problem
Existing LED drive circuits are vulnerable to external environmental noise due to the use of a fixed reference voltage, leading to inaccurate drive voltage adjustments and instability in LED array operation.
Innovation Solution
An LED drive circuit and method that periodically updates a reference voltage by averaging feedback drive voltages from LED strings, generating a control signal to adjust the drive voltage, and sets irregular sampling times to mitigate noise effects, ensuring stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed reference voltage is used to control LED drive voltage, then the control method is simple, but the system becomes vulnerable to external environmental noise
Solution Approach 1:
The patent transitions from a static fixed reference voltage to a dynamic reference voltage that is periodically updated based on feedback from LED strings. This dynamic adjustment allows the reference voltage to adapt to changing environmental conditions and track the actual operating characteristics of the LED array, thereby maintaining control accuracy despite external noise interference.
Solution Approach 2:
The patent introduces a feedback mechanism where the actual drive voltage from LED strings is continuously monitored and used to update the reference voltage. This closed-loop feedback system enables the controller to compensate for noise and environmental variations by adjusting the reference voltage based on real-time measurements, thereby improving system reliability without significantly increasing complexity.
2Productivity
If drive voltage is adjusted based on measured voltage including noise components, then the control responds to actual voltage changes, but the control becomes inaccurate due to noise
Solution Approach 1:
The patent applies preliminary action by periodically updating the reference voltage in advance based on feedback from LED strings before using it for subsequent control decisions. This proactive update mechanism allows the system to anticipate and compensate for noise effects, maintaining measurement precision while preserving rapid control response capability.
Solution Approach 2:
The patent implements periodic action by updating the reference voltage at regular intervals based on feedback measurements. This periodic更新 mechanism filters out noise through time-averaging effects while maintaining responsiveness to genuine voltage changes, thereby improving measurement accuracy without sacrificing control speed.
3Ease of operation
If regular sampling time points are used for feedback voltage, then the control is systematic, but the system cannot effectively mitigate noise effects
Solution Approach 1:
The patent introduces dynamic sampling by adjusting sampling time points based on the operational state of the LED array and environmental conditions. This dynamic approach allows the system to optimize sampling moments for maximum noise immunity while maintaining systematic control through programmable timing mechanisms, thereby improving reliability without sacrificing ease of operation.
Data Source
AI summary
An LED drive method is disclosed. In this way, the LED drive method allows not only the reference voltage to be periodically updated on the basis of the feedback drive voltages but also the drive voltage control signal to be generated using the updated reference voltage, in order to adjust the LED drive voltage applied to the LED array. Therefore, the LED drive circuit is hardly affected by the external environmental noise.