Voltage Converter Frequency Adjustment for Light Load Stability
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Solution Overview
Problem
Conventional voltage converters face instability and high ripple issues when the input voltage is close to the output voltage or when the load is light, due to limitations in minimum turn-on time, leading to unstable output voltage and increased switching loss.
Innovation Solution
A voltage converter that detects the pulse width in each work cycle and adjusts the switching frequency based on the detected pulse width, reducing the duty ratio and maintaining a stable output voltage by reducing the switching frequency when the input voltage is close to the output voltage or the load is light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the turn-on time is shortened to ensure stable output voltage when input voltage is close to output voltage, then the output voltage stability is improved, but the switching frequency increases and causes prominent ripples and instability
Solution Approach 1:
The patent implements dynamic adjustment of the switching frequency based on real-time detection of the turn-on time. When the turn-on time approaches the minimum threshold, the system automatically reduces the switching frequency to prevent instability. This dynamic adaptation allows the voltage converter to maintain optimal performance across varying operating conditions, resolving the contradiction between maintaining stable output voltage and avoiding excessive switching frequency that causes ripples.
2Speed
If the switching frequency is increased to handle shorter work cycles, then the response speed is improved, but the output voltage becomes unstable with big ripples
Solution Approach 1:
The patent employs a feedback mechanism where the turn-on time is continuously detected and used to adjust the switching frequency. This closed-loop control ensures that when the turn-on time becomes too short (which would normally require higher switching frequency for stability), the system responds by reducing the switching frequency to an appropriate level, thereby preventing output voltage instability and ripples while maintaining adequate response speed.
3Loss of energy
If the duty ratio is reduced to maintain stable frequency switching, then the switching loss is reduced, but the turn-on time becomes limited by minimum pulse width constraints
Solution Approach 1:
The patent dynamically changes the switching frequency parameter based on the detected turn-on time. By adjusting the switching frequency in response to the turn-on time conditions, the system can maintain an appropriate duty ratio that reduces switching losses while ensuring the turn-on time remains above the minimum pulse width constraint. This parameter adaptation allows the system to operate efficiently without being limited by minimum turn-on time constraints.
Data Source
AI summary
Systems, circuits, devices and methods related to voltage converters. In some embodiments, a control system for a voltage converter can include a driving unit configured to generate a driving signal having a pulse width and a frequency. The driving signal is provided to a voltage conversion circuit to control conversion of an input voltage into an output voltage. The control system can further include a modulation unit configured to modulate the pulse width of the driving signal based on the output voltage to thereby allow adjustment of the output voltage. The control system can further include a control circuit configured to adjust the frequency of the driving signal based on the modulated pulse width. Such a control system can be useful in situations such as when the output voltage is close to the input voltage, or when a load being driven by the output voltage is relatively low.