Power Circuit Switching Frequency Control for Load Fluctuations
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Solution Overview
Problem
Existing PWM control power circuits have limited responsiveness to load fluctuations due to restricted switching frequency, which affects the ability to maintain stable output voltage during rapid changes in load conditions.
Innovation Solution
A power circuit configuration that includes a switching transistor, a drive circuit, an error calculation circuit, a compensating circuit, a comparator circuit, and a control circuit, which dynamically adjusts the frequency of the drive signal based on output voltage fluctuations, allowing for increased responsiveness to load changes by comparing feedback current with control values and adjusting the switching frequency accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the switching frequency of the switching transistor is increased to improve responsiveness to load fluctuations, then the responsiveness is improved, but the power consumption and voltage ripples increase
Solution Approach 1:
The patent applies dynamics by making the switching frequency adjustable rather than fixed. The control circuit dynamically changes the switching frequency based on load conditions: using a first (lower) frequency during normal operation to minimize power consumption, and switching to a second (higher) frequency when voltage fluctuation exceeds a threshold to improve responsiveness. This dynamic adaptation resolves the contradiction between responsiveness and power consumption.
Solution Approach 2:
The patent changes the parameter of switching frequency based on operating conditions. By monitoring voltage fluctuation and adjusting the frequency parameter accordingly (lower frequency for stable loads, higher frequency for fluctuating loads), the system optimizes both power consumption and responsiveness, resolving the technical contradiction between these two parameters.
2Speed
If the switching frequency of the switching transistor is increased to improve responsiveness to load fluctuations, then the responsiveness is improved, but the voltage ripples increase
Solution Approach 1:
The system dynamically adjusts switching frequency based on voltage stability requirements. During normal operation with stable voltage, a lower frequency is used. When voltage fluctuation detected by the detection circuit exceeds a threshold, the control circuit switches to a higher frequency to quickly respond and restore voltage stability, thus resolving the contradiction between responsiveness and voltage stability.
Solution Approach 2:
The patent employs feedback through a voltage detection circuit that continuously monitors output voltage fluctuations. This feedback signal is fed to the control circuit, which adjusts the switching frequency accordingly. When voltage instability is detected, the system increases frequency to restore stability, creating a closed-loop control that resolves the contradiction between responsiveness and voltage stability.
3Device complexity
If a fixed switching frequency is used to simplify the control circuit, then the device complexity is reduced, but the responsiveness to load fluctuations is limited
Solution Approach 1:
The patent implements a dynamic frequency adjustment mechanism that adds minimal complexity to the control circuit. The detection circuit monitors voltage and the control circuit switches between two predefined frequencies based on threshold comparison. This simple dynamic approach significantly improves responsiveness without introducing complex control algorithms or multiple frequency generations, thus resolving the contradiction between device complexity and responsiveness.
Data Source
AI summary
According to an embodiment, provided is a power circuit including: a switching transistor connected between an input terminal and an output terminal; a drive circuit configured to output a drive signal that controls on/off of the switching transistor; an error calculation circuit configured to output an error value between the output voltage and reference voltage; a determination circuit configured to compare a reference value obtained from the error value with a predetermined threshold value and then output a control signal; and a control circuit configured to control a frequency of the drive signal in response to the control signal.