Switched Capacitor DC-DC Converter with External and Internal Flying Capacitors
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Solution Overview
Problem
Existing switched capacitor DC-DC converters face challenges in maintaining high energy conversion efficiency when DC input voltage varies widely and load power fluctuations occur, particularly in compact portable devices like head-wearable hearing devices, due to limitations in capacitance and switching frequency.
Innovation Solution
An integrated circuit switched capacitor DC-DC converter design featuring a first switched capacitor converter with external flying capacitors and a second converter with internal flying capacitors, controlled by a controller to dynamically select topologies and adjust switching frequency, allowing for efficient voltage conversion across varying input and output conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If fully integrated switched capacitor DC-DC converters with large number of flying capacitors are used, then intrinsic energy efficiency is maintained high despite large variation of DC input voltage, but the converters are unable to support large load power levels due to limited capacitance of integrated flying capacitors
Solution Approach 1:
The power conversion system is divided into two separate switched capacitor converters: a first converter with external flying capacitors for handling large load power bursts, and a second converter with integrated flying capacitors for maintaining high efficiency at normal operating levels. This segmentation allows each converter to be optimized for its specific function, resolving the contradiction between efficiency and power capability.
2Adaptability or versatility
If switched capacitor DC-DC converter operates with varying DC input voltage from battery sources, then the converter can adapt to battery charge state, but energy conversion efficiency deteriorates when voltage varies over large range
Solution Approach 1:
The controller dynamically selects from multiple converter topologies in both the first and second switched capacitor converters, adjusting the circuit configuration in real-time based on the battery voltage level and load conditions. This dynamic adaptation allows the system to maintain high energy conversion efficiency across the full battery voltage range from 3.0V to 4.2V.
3Power
If large number of external flying capacitors and associated wire routing are used, then switched capacitor DC-DC converter can support large load power levels, but the design becomes impractical for compact portable devices
Solution Approach 1:
The system separates the flying capacitor functions into two groups: a minimal set of external flying capacitors for power burst handling, and integrated flying capacitors for normal operation. This segmentation dramatically reduces the number of external components and wire routing requirements compared to using only external capacitors, making the design practical for compact portable devices while still supporting large load power levels when needed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances energy conversion efficiency by enabling high power bursts without compromising efficiency at normal load levels, reducing external components, and minimizing electromagnetic interference.
Implementation Method 1
a first switch array comprising a plurality of individually controllable semiconductor switches connectable to at least one external flying capacitor to form one or more individual converter topologies of the first switched capacitor converter for converting the battery supply voltage into an intermediate voltage
Implementation Method 2
a second switch array comprising a plurality of individually controllable semiconductor switches and a plurality of internal flying capacitors, e.g. two, three, or four, configurable to form a plurality of individual converter topologies for converting the intermediate voltage into a DC output voltage
Data Source
AI summary
The present disclosure relates to an integrated circuit switched capacitor DC-DC converter which comprises a first switched capacitor converter based on at least one external flying capacitor and a second switched capacitor converter which comprises a plurality of internal flying capacitors. A controller is configured to select a converter topology of the first switched capacitor converter and a select a converter topology of the second switched capacitor converter.