Switch-Mode Power Supply Peak Current Mode Control
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Solution Overview
Problem
Existing switch-mode power supplies face challenges in implementing adaptive slope compensation for peak current mode control, especially under time-variant input voltages and varying load conditions, which affects stability and efficiency.
Innovation Solution
A peak current mode controlling method and module that generates an off-time control signal based on input and output voltages, a reference current signal, and a trigger signal to manage the operation of a power conversion module, ensuring consistent off-time intervals and pulse-width-modulating control, thereby maintaining continuous-conduction mode without the need for slope compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adaptive slope compensation is implemented for peak current mode control under time-variant input voltages and varying load conditions, then the stability is improved, but the device complexity increases
Solution Approach 1:
The patent extracts and eliminates the slope compensation function from the control system. By using fixed off-time control where the off-time is determined solely by the reference current signal and load conditions rather than requiring adaptive slope compensation, the system achieves stability without the complex adaptive compensation circuitry that would otherwise be needed for peak current mode control under varying conditions.
Solution Approach 2:
Instead of using peak current mode control with adaptive slope compensation to achieve stability, the patent inverts the approach by using fixed off-time control where the off-time is set based on reference current signals. This inverted control strategy achieves the same stability goal without requiring the complex adaptive compensation mechanisms.
2Loss of energy
If adaptive slope compensation is implemented for different load conditions, then the efficiency is improved, but the ease of operation deteriorates
Solution Approach 1:
The patent removes the need for adaptive slope compensation by extracting the control function to a simpler fixed off-time mechanism. The off-time is determined by reference current signals that automatically adapt to load conditions without requiring complex compensation algorithms, thereby maintaining efficiency while greatly simplifying operation.
Solution Approach 2:
The control system uses self-service by allowing the off-time to be automatically determined by the reference current signal and load conditions without requiring external adaptive compensation. The system self-regulates based on inherent electrical characteristics, eliminating the need for complex operational adjustments.
3Device complexity
If fixed slope compensation is used for DC input voltage, then the device complexity is reduced, but the adaptability deteriorates
Solution Approach 1:
The patent introduces dynamics by making the off-time adaptive to load conditions through reference current signals. While the control mechanism itself remains simple (fixed off-time control), the system dynamically adjusts its behavior based on actual operating conditions, achieving both simplicity and adaptability simultaneously.
Solution Approach 2:
The patent changes the control parameter from fixed peak current mode with adaptive slope compensation to fixed off-time control where the off-time duration varies based on reference current signals. This parameter change allows the system to maintain simple circuitry while adapting to different load conditions through natural electrical behavior.
Data Source
AI summary
A controlling module includes a current-command generating unit for generating reference current signal based on an output voltage of a power conversion module, a current sensor configured to sense an inductor current of the power conversion module and generate current sense signal, a current comparator for generating current compare signal when the current sense signal equaling to the reference current signal, and an off-time controller for generating off-time control signal based on an input voltage and the output voltage of the power conversion module. The controlling module further includes a time-base counter and a peak-current controlling unit. The time-base counter receives the current compare signal and the off-time control signal, and generates a trigger signal when an off-time interval established by the off-time control signal elapses. The peak-current controlling unit makes a power switch of the power conversion module in a conduction state based on the trigger signal.