Buck-Boost Converter Hysteresis Control Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional DC-DC converters, such as buck-boost converters, have relatively low conversion efficiency when the input voltage is close to the output voltage, limiting the extension of battery life in mobile devices without increasing their size.
Innovation Solution
A buck-boost converter with a hysteresis-based control system that includes a converting circuit, a ripple injector, and a hysteresis comparator to generate switching control signals, allowing for efficient voltage stepping down, stepping up, or maintaining a voltage level close to the input voltage, thereby achieving improved conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional DC-DC converters are used, then voltage conversion is achieved, but conversion efficiency deteriorates when input voltage is close to output voltage
Solution Approach 1:
The converter dynamically switches between buck mode, boost mode, and buck-boost mode based on the relationship between input and output voltages. When Vin < Vout, it operates in boost mode; when Vin > Vout, it operates in buck mode; when Vin ≈ Vout, it operates in buck-boost mode. This dynamic operation ensures high conversion efficiency across the entire voltage conversion range.
Solution Approach 2:
The converter changes its operating parameters (switching states of transistors, configuration of switches) based on the voltage relationship. By adjusting the switching patterns and operational modes according to the input-output voltage differential, the converter maintains optimal efficiency regardless of whether the input voltage is lower than, higher than, or close to the output voltage.
2Duration of action of moving object
If battery capacity is increased to extend usage time, then hours of use increase, but device size increases
Solution Approach 1:
The patent converts the previously harmful low-efficiency operation mode (when Vin ≈ Vout) into a beneficial buck-boost mode that achieves high efficiency. By introducing the ripple injection mechanism and hysteresis-based control, the converter transforms what was once a wasteful operating condition into an efficient power conversion scenario, thereby extending battery life without increasing device size.
Solution Approach 2:
The converter uses feedback mechanisms including hysteresis comparison and ripple injection to continuously monitor and adjust its operation. The hysteresis comparator detects voltage differences and triggers appropriate mode switching, while the ripple injection ensures proper operation during buck-boost mode. This feedback control optimizes power conversion efficiency, allowing smaller batteries to provide longer usage time.
3Loss of energy
If hysteresis-based control with ripple injection is implemented, then conversion efficiency improves, but device complexity increases
Solution Approach 1:
The converter uses its own output ripple voltage as the injection signal, eliminating the need for external oscillation circuits or additional signal generation components. The hysteresis comparator uses the natural voltage ripple to trigger mode switching, and the control circuit automatically adjusts switching patterns based on real-time voltage conditions. This self-service approach achieves high efficiency while minimizing additional circuit complexity.
Data Source
AI summary
A buck-boost converter includes: a converting circuit; a ripple injector; a hysteresis comparator; and a switching controller. The converting circuit is configured to generate an output voltage by adjusting an input voltage in a buck mode, a boost mode, and a buck-boost mode. The ripple injector is configured to generate a ripple based on switching signals corresponding to switching operations of the converting circuit. The hysteresis comparator outputs at least one switching control signal by comparing an output control voltage with a feedback voltage generated by adding the ripple to a divided voltage generated by performing a voltage division on the output voltage. The switching controller is configured to change a current flow path of the converting circuit based on the at least one switching control signal.