Current Mode Power Converter Compensation Circuit
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Solution Overview
Problem
Existing current mode power converters face issues with loose accuracy in slope compensation, affecting protection functions and requiring complex compensation circuits, which increase costs.
Innovation Solution
A method and circuit for controlling current mode power converters that generate first and second compensation signals to adjust the current signal, with the slope of the first compensation signal decreasing when the power transistor is turned on and the slope of the second compensation signal increasing, both signals being offset to zero, to achieve precise output power limiting and slope compensation without interfering with each other.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional single compensation scheme is used, then circuit complexity is reduced, but compensation accuracy deteriorates and protection function is affected
Solution Approach 1:
The patent divides the single compensation function into two separate compensation circuits: a first compensation circuit for output power limit compensation and a second compensation circuit for slope compensation. Each circuit independently processes its specific compensation signal without interfering with the other, thereby improving compensation accuracy while keeping each individual circuit relatively simple.
Solution Approach 2:
The patent introduces separate compensation signals (first compensation signal and second compensation signal) that act as intermediaries to independently adjust the current signal for different purposes. The first compensation signal specifically addresses output power limit accuracy, while the second compensation signal addresses slope compensation accuracy, allowing each to optimize its function without compromise.
2Reliability
If slope compensation is applied, then protection function is improved, but output power limit compensation accuracy deteriorates
Solution Approach 1:
The patent segments the compensation functions by creating independent first and second compensation circuits. The first compensation circuit specifically handles output power limit compensation with high accuracy, while the second compensation circuit handles slope compensation for protection functions. This segmentation eliminates the interference between the two functions that plagues traditional single-compensation schemes.
Solution Approach 2:
Each compensation circuit is optimized for its specific function: the first compensation circuit is designed with local quality optimized for output power limit accuracy, while the second compensation circuit is designed with local quality optimized for slope compensation and protection functions. This localized optimization allows each circuit to excel at its specific task without compromising the other.
Data Source
AI summary
A method and circuit for providing compensation of a power converter is proposed. A current sense circuit is coupled to receive a switching current for generating a current signal. A signal generation circuit is developed to generate a first compensation signal and a second compensation signal for adjusting the current signal. The first compensation signal is coupled to adjust the current signal for the output power limit of the power converter. The second compensation signal is coupled to adjust the current signal for the slope compensation. The slope of the first compensation signal is decreased when the power transistor is turned on. The slope of the second compensation signal is increased in response to the turn on of the power transistor.