Average Current Regulator ON-Time Controller LED Stability
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Solution Overview
Problem
Existing current regulators primarily control peak current, leading to instability in average current, which is critical for applications like LED lighting where uniform brightness is necessary, and are prone to noise errors due to power switch coupling and reverse diode current.
Innovation Solution
An average current regulator with an ON-time controller that adjusts the PWM signal based on feedback signals to ensure the average output current reaches a target value by calculating and controlling the ON-time of power transistors, effectively filtering noise and maintaining stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If peak current control is used in conventional current regulators, then the control mechanism is simple, but the average current stability deteriorates
Solution Approach 1:
The invention changes the control parameter from peak current to average current by introducing an ON-time controller that measures and regulates the average current based on the relationship between ON-time and average current, thereby improving average current stability while maintaining reasonable control complexity
Solution Approach 2:
The invention implements a feedback mechanism where the ON-time controller receives feedback signals related to output current and adjusts the PWM signal accordingly to maintain stable average current, resolving the contradiction between simple control and stable average current
2Stability of the object's composition
If conventional average current control is implemented, then average current regulation is achieved, but noise accuracy deteriorates due to power switch coupling and reverse diode current
Solution Approach 1:
The invention extracts and eliminates the harmful noise components caused by power switch coupling and reverse diode current from the feedback signal through careful circuit design and signal processing, thereby improving measurement precision while maintaining average current regulation
Solution Approach 2:
The invention converts the potentially harmful noise from power switches and reverse diodes into manageable signals by designing the feedback circuit to distinguish between useful current information and noise, thereby improving overall measurement accuracy
3Illumination intensity
If LED circuits require stable average current for uniform brightness, then brightness uniformity is improved, but control precision requirements increase
Solution Approach 1:
The invention changes the control approach to focus on average current rather than peak current, which directly correlates with LED brightness perception, thereby achieving brightness uniformity with appropriate control precision
Solution Approach 2:
The invention implements feedback control that continuously monitors and adjusts the average current to maintain uniform LED brightness, balancing the precision requirements with practical performance
Data Source
AI summary
The present invention discloses an average current regulator, a driver circuit of an average current regulator, and a method for regulating an average current. The average current regulator includes: a power stage including at least one power transistor which switches according to a pulse width modulation (PWM) signal to convert an input voltage to an output current; a feedback circuit coupled to the power stage, for generating a feedback signal; an ON-time controller coupled to the feedback circuit, for receiving the feedback signal and generating an ON-time signal according to the feedback signal and an average reference signal relating to a target average current; and a PWM controller, for generating the PWM signal according to the ON-time signal to regulate the average of the output current to the target average current.