Buck Converter Switch Timing for Voltage Overshoot Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing buck converters face limitations in recovery time and output voltage regulation, particularly experiencing output voltage overshoot and poor recovery due to steep changes in load current, with existing solutions failing to effectively prevent undershoot and overshoot.
Innovation Solution
A buck converter with a switch operable between two states to oppose voltage decreases and increases, featuring a circuit that determines the time period of voltage decrease and calculates the switch's transition time based on the duty cycle to prevent output voltage from exceeding a reference value, utilizing a memory device, comparators, and current generators to control the switch's state transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a feedback loop is used to track load current changes, then output voltage undershoot is minimized, but output voltage overshoot occurs and recovery time increases
Solution Approach 1:
The circuit determines the time period during which the output voltage is decreasing before the voltage actually reaches its minimum point. Based on this predetermined time period and the duty cycle, the switch is turned off at an optimized time that prevents subsequent voltage overshoot. This preliminary timing action allows the system to prepare for the voltage transition in advance, achieving both fast recovery and preventing overshoot.
2Reliability
If the switch remains in the first state longer to prevent voltage undershoot, then output voltage stability improves, but recovery time increases
Solution Approach 1:
The invention dynamically adjusts the switch off-time based on the determined time period of voltage decrease and the duty cycle. Rather than using a fixed or overly conservative on-time, the system calculates the precise moment to transition the switch from the first state to the second state, optimizing the duration of action to be just sufficient for stability without excessive delay.
3Manufacturing precision
If synchronous converter topology is used to address load current variation, then output voltage regulation improves, but output voltage overshoot is generated
Solution Approach 1:
The circuit continuously monitors the output voltage and determines the time period during which it is decreasing. This feedback information is used to calculate the optimal switch transition time, creating a closed-loop control system that adjusts the switch timing based on actual voltage behavior, thereby preventing overshoot while maintaining good regulation.
Data Source
AI summary
A switching converter, which produces an output voltage, contains a switch operable between a first state for opposing a decrease in the output voltage and a second state for opposing an increase in the output voltage. The converter also contains a circuit adapted to determine a time period during which the output voltage is decreasing, wherein during the time period the switch is in the first state. The circuit also calculates, based on the time period, a time to turn the switch from the first state to the second state to prevent the output voltage increasing above a reference value. Optionally, the time to turn the switch to the second state is based on a duty cycle of the converter.