Buck-Boost DC-DC Converter with Shared Capacitor Array
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Capacitor-limited DC-DC converters face inefficiencies and area constraints due to high overhead in reconfiguring arrays and large output ripples, especially when dealing with high input and output DC levels, and capacitor reliability issues.
Innovation Solution
A novel Buck-Boost DC-DC converter architecture combines a linear regulator with a switched-capacitor converter, sharing the same capacitor array and feedback loop, allowing automatic reconfiguration between Buck and Boost configurations to optimize performance and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a multiple-capacitor-array topology is used to achieve different conversion ratios, then the power efficiency is improved, but the converter complexity and power consumption increase due to array re-configuration overhead
Solution Approach 1:
The patent combines a switched-capacitor DC-DC converter and a linear regulator into a single integrated circuit that shares a common capacitor array. The capacitor array can be reconfigured to serve different functions: as flying capacitors for the switched-capacitor converter or as output capacitors for the linear regulator, eliminating the need for separate capacitor arrays for each converter type.
Solution Approach 2:
The common capacitor array is designed to perform multiple functions depending on the operating mode. The same physical capacitors can be switched between different configurations to support both switched-capacitor and linear regulator operations, as well as different conversion ratios, reducing overall device complexity while maintaining efficiency.
2Reliability
If capacitor stacking is used to handle high input and output DC levels, then the voltage rating constraint is satisfied, but the silicon area increases due to area constraints
Solution Approach 1:
The patent implements dynamic reconfiguration of the capacitor array where the same physical capacitors can be connected in series or parallel depending on the operating conditions. This dynamic switching allows the system to handle high voltage requirements through series connections when needed, while using parallel connections for lower voltage operations, thereby reducing the total silicon area required compared to having dedicated capacitor stacks for different voltage levels.
3Ease of manufacture
If a switched-capacitor DC-DC converter is used, then a fully-integrated solution is achieved, but large output ripples are produced
Solution Approach 1:
The patent introduces a linear regulator as an intermediary stage that follows the switched-capacitor DC-DC converter. The linear regulator acts as a mediator that filters out the output ripples generated by the switched-capacitor converter while maintaining the fully-integrated advantage. The shared capacitor array serves as both the energy storage for the switched-capacitor converter and the output filter for the linear regulator.
Data Source
AI summary
An automatically reconfigurable Buck-Boost DC-DC converter having an input supply and an output voltage includes a linear regulator (LDO) for Buck configuration; a switched-capacitor DC-DC converter; a capacitor and switch array, and a gain selector to switch between the linear regulator (LDO) when an output DC level is higher than an input DC level (Buck configuration) and the switched-capacitor DC-DC converter when the output DC level is lower than the input DC level (Boost configuration).