Buffer Circuit Isolation in Constant ON-Time Converters
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Solution Overview
Problem
Constant ON-time converters experience sub-harmonic oscillations and instability due to the direct coupling of the slope compensation circuit with the feedback circuit, which affects the accuracy of the output signal.
Innovation Solution
Incorporating a buffer circuit between the feedback circuit and the slope compensation circuit to isolate their influence, allowing the comparison circuit to generate a control signal based on a buffered feedback signal and a slope compensation signal, thereby improving output accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the slope compensation circuit is directly coupled with the feedback circuit, then sub-harmonic oscillation is avoided and converter stability is improved, but the output accuracy deteriorates due to influence on the feedback signal
Solution Approach 1:
The patent introduces a buffer circuit as an intermediary component between the feedback circuit and the slope compensation circuit. This buffer circuit isolates the direct coupling path, allowing the slope compensation signal to be generated without directly influencing the feedback signal, thus resolving the contradiction between stability and accuracy
2Device complexity
If the feedback signal is directly used in the comparison circuit with slope compensation, then the circuit structure remains simple, but the output accuracy deteriorates due to signal interference
Solution Approach 1:
The buffer circuit serves as a simple intermediary that adds minimal complexity to the overall structure while effectively isolating the feedback signal from slope compensation interference, maintaining circuit simplicity while improving output accuracy
Data Source
AI summary
A constant ON-time converter is disclosed. The constant ON-time converter comprises a feedback circuit, a slope compensation circuit and a buffer circuit. The feedback signal comprises an output configured to provide a feedback signal indicating an output voltage of the constant ON-time converter. The slope compensation circuit comprises an output configured to provide a slope compensation signal. The buffer circuit is coupled between the output of the feedback circuit and the output of the slope compensation circuit to avoid the feedback signal and the output voltage of the constant ON-time converter is influenced by the slope compensation signal.