Switching Power Supply Control With Switchable Load-Line Feedback
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Solution Overview
Problem
Existing switching power supplies face challenges in independently adjusting overshoot and undershoot of output voltage during load fluctuations and in seamlessly switching between enabling and disabling the load line function without affecting other control circuits.
Innovation Solution
The power supply controller incorporates a modified error amplifier that can switch between modes using an integral voltage to enable or disable the load line function, allowing independent adjustment of load response characteristics and load line characteristics, and includes a differential current sensor for precise control of coil current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the load line function is enabled to adjust output voltage according to load current, then output voltage accuracy under varying load conditions is improved, but the complexity of the control circuit increases
Solution Approach 1:
The patent combines the load line function with the existing error amplifier by adding a switchable integral voltage input terminal. This merging approach integrates the load line capability into the existing control circuit rather than adding a separate complex circuit, thereby improving output voltage accuracy under varying load conditions while minimizing increases in control circuit complexity
Solution Approach 2:
The patent implements a switchable integral voltage input terminal that can dynamically switch between enabled and disabled states. This dynamic configuration allows the control circuit to adapt its complexity based on operational requirements, enabling the load line function only when needed to maintain output voltage accuracy while simplifying the circuit during operations where load line compensation is not required
2Adaptability or versatility
If the integral voltage input terminal is made switchable to enable/disable load line function, then adaptability of the control circuit is improved, but the complexity of the error amplifier increases
Solution Approach 1:
The patent segments the error amplifier into distinct functional sections: a first input terminal for error signals, a second input terminal for integral voltages with switchable enable/disable capability, and separate output terminals. This segmentation allows the integral voltage input to be independently controlled and switched without affecting the core error amplification function, thereby improving adaptability while managing error amplifier complexity through modular design
3Ease of operation
If seamless switching between load line enabled/disabled modes is implemented, then ease of operation is improved, but the difficulty of detecting and measuring control states increases
Solution Approach 1:
The patent incorporates a switch control terminal that receives external control signals to seamlessly switch the load line function between enabled and disabled modes. The switchable integral voltage input terminal responds to these control signals, and the circuit maintains proper feedback loops in both modes, enabling easy operational switching while the feedback mechanism itself provides the means for detecting and measuring the current control state through the feedback voltage signals
Data Source
AI summary
A power supply controller controlling an output circuit of a switching power supply that generates an output voltage from an input voltage includes: an error amplifier generating an error signal according to an error between a feedback voltage corresponding to the output voltage and a predetermined reference voltage; a current sensor generating a current detection signal according to a coil current flowing the output circuit; a duty signal generation circuit generating a duty signal upon receiving the current detection and error signals; and a drive signal generation circuit generating a drive signal for the output circuit upon receiving the duty signal, wherein the error amplifier is switched, by a mode switching signal, between a first mode of generating the error signal using an integral voltage by integrating a difference value between the reference and feedback voltages, and a second mode of generating the error signal without using the integral voltage.