Buck Switching Power Supply Overshoot Suppression With Parallel GaN Switch
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Bucking switching power supply devices experience sharp output current falls leading to overshoots in output voltage, which are not effectively managed by existing technologies.
Innovation Solution
A switching power supply device with a controller that turns on and off switches to suppress overshoots by maintaining specific switch configurations, including using a third switch in parallel with the inductor to manage inductor current and output voltage, and employing a detector to sense and respond to overshoots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional switching control is used in a bucking switching power supply device, then the device can operate with simple control logic, but sharp falls in output current cause overshoots in output voltage that are not effectively managed
Solution Approach 1:
The controller monitors the output voltage and detects overshoot conditions, then adjusts the switch control signals accordingly. This feedback mechanism allows the system to automatically respond to voltage deviations and restore stability without requiring complex external control circuits.
Solution Approach 2:
The controller dynamically changes the operating state of the switching elements based on detected overshoot conditions. By transitioning between different switch configurations (normal operation mode vs. overshoot suppression mode), the system adapts to varying conditions and effectively manages voltage stability.
2Reliability
If additional switches are added to suppress overshoots, then output voltage stability improves, but the device complexity and number of components increases
Solution Approach 1:
The third switch is designed to serve multiple functions: it acts as a normal switching element during regular operation and simultaneously functions as an overshoot suppression mechanism when activated. This multi-functionality allows the system to gain enhanced voltage stability without proportionally increasing component count.
Solution Approach 2:
The switching elements, particularly the third switch, are configured to automatically respond to overshoot conditions through controller-directed gate signal adjustments. The system uses its own existing components in novel configurations to suppress overshoots, rather than requiring entirely separate dedicated suppression circuits.
3Speed
If the switching frequency is increased to improve response time, then overshoot detection and suppression becomes faster, but noise frequency variation increases
Solution Approach 1:
The controller employs periodic switching actions with optimized duty cycles to manage the trade-off between response speed and noise generation. By using controlled periodic gating signals rather than continuous high-frequency switching, the system achieves adequate response time while limiting noise frequency variation to manageable levels.
Data Source
AI summary
A switching power supply device includes a first switch with a first terminal connectable to an application terminal for the input voltage and a second terminal connectable to the first terminal of an inductor; a second switch with a first terminal connectable to the first terminal of the inductor and a second terminal connectable to an application terminal for a voltage lower than the input voltage; a third switch being a GaN semiconductor element and connectable in parallel with the inductor; a detector detecting occurrence or a sign or occurrence of an overshoot in the output voltage; and a controller. The controller produces, after occurrence or a sign of occurrence of an overshoot in the output voltage is detected by the detector until settlement of the overshoot in the output voltage, a control state in which to keep the first and second switches off and the third switch on.