Switching Power Supply Circuit Feedback Loop Design
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Solution Overview
Problem
Conventional switching power supply circuits have a slow response time to load variations, resulting in a prolonged period to stabilize and supply a stable voltage to loads through transmission lines, which is inadequate for modern electronic devices with rapid load changes.
Innovation Solution
A switching power supply circuit is designed with a voltage conversion unit, a signal generation unit that monitors voltage drops in the transmission line, and a low pass filter to generate a control signal, ensuring phase margin and improving response speed by widening the frequency band of the feedback loop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional switching power supply circuit is used to supply power through a transmission line, then the voltage drop in the transmission line is compensated by outputting a higher voltage, but the response time to load variations becomes long and the response speed is low
Solution Approach 1:
The patent implements a feedback mechanism where the output voltage is monitored and fed back to the control circuit. The control circuit compares the feedback voltage with a reference voltage and adjusts the duty cycle of the switching element accordingly. This closed-loop feedback system enables the power supply to automatically respond to load variations and maintain stable output voltage, resolving the contradiction between voltage stability and response speed by using dynamic feedback control rather than static voltage compensation.
Solution Approach 2:
The patent employs dynamic control of the switching element's duty cycle based on real-time load conditions. The control circuit dynamically adjusts the on-time and off-time of the switching element to maintain stable output voltage despite load variations. This dynamic adjustment mechanism allows the system to adapt quickly to changing load conditions, improving response speed while maintaining voltage stability.
2Reliability
If the output voltage is increased to compensate for transmission line voltage drop, then the load receives adequate voltage, but the period to stabilize voltage after load variation is prolonged
Solution Approach 1:
The feedback mechanism continuously monitors the output voltage and immediately responds to deviations caused by load variations. When a load change occurs, the feedback circuit detects the voltage deviation and triggers the control circuit to adjust the duty cycle, initiating corrective action without delay. This real-time feedback eliminates the prolonged stabilization period by enabling immediate response to voltage deviations.
Solution Approach 2:
The patent replaces traditional mechanical or passive voltage regulation mechanisms with an active electronic control system. The control circuit uses electronic switching and signal processing to rapidly adjust the output voltage, substituting slow mechanical adjustment mechanisms with fast electronic control. This substitution significantly reduces the stabilization time while maintaining voltage stability.
Data Source
AI summary
There is provided a switching power supply circuit (1) for supplying a power supply voltage to a load through a transmission line PL. The switching power supply circuit (1) includes: a voltage conversion unit (11) for inputting thereinto an input voltage VIN and a control signal Vc, converting the input voltage VIN into an output voltage Vo having a magnitude corresponding to the control signal Vc, and outputting the output voltage Vo to the transmission line PL; a signal generation unit (12) for monitoring a load current ILOAD flowing through the transmission line PL and generating a signal corresponding to a voltage dropped in the transmission line PL; and a low pass filter (13) for outputting the signal generated in the signal generation unit (12) to the voltage conversion unit (11) as the control signal Vc.