Hybrid DC-DC Converter for Cold Start and Efficient Operation
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Solution Overview
Problem
Existing DC-DC converters for IoT and WSN devices face a trade-off between efficiency and cold-start capability, which is undesirable for applications that require both high efficiency and reliable startup from energy harvesters.
Innovation Solution
A hybrid DC-DC converter design that combines a Dickson charge pump for cold-start capability with a Series-parallel or Makowski charge pump for high efficiency, sharing capacitors between the two designs to minimize footprint and bill of materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a DC-DC converter is optimized for high conversion efficiency, then energy efficiency is improved, but cold-start capability deteriorates
Solution Approach 1:
The DC-DC converter is divided into two distinct circuits: a first DC-DC converter circuit optimized for cold-start capability and a second DC-DC converter circuit optimized for high conversion efficiency. This segmentation allows each circuit to be independently optimized for its specific function, resolving the contradiction between efficiency and cold-start capability.
Solution Approach 2:
The system dynamically switches between the first DC-DC converter circuit during cold-start conditions and the second DC-DC converter circuit during normal operation. This dynamic operation allows the system to adapt its conversion strategy based on operational conditions, achieving both cold-start capability and high efficiency at different times.
2Reliability
If two separate DC-DC converter circuits are used to achieve both cold-start capability and high efficiency, then functional requirements are met, but device complexity and footprint increase
Solution Approach 1:
The first and second DC-DC converter circuits share common components including input capacitor C1, output capacitor C2, inductor L1, and diode D1. This merging of components reduces the overall device complexity and footprint while maintaining the functional benefits of having two specialized conversion circuits.
Solution Approach 2:
Common components serve multiple functions: the input capacitor C1 and inductor L1 are used by both converter circuits, the output capacitor C2 and diode D1 serve both circuits' output stages. This multi-functionality reduces the total component count and simplifies the overall device structure.
3Loss of energy
If two separate DC-DC converter circuits are implemented, then both cold-start and efficiency requirements are met, but bill of materials and footprint increase
Solution Approach 1:
The first and second DC-DC converter circuits share common components including input capacitor C1, output capacitor C2, inductor L1, and diode D1. This merging of components reduces the overall device complexity and footprint while maintaining the functional benefits of having two specialized conversion circuits.
Solution Approach 2:
Common components serve multiple functions: the input capacitor C1 and inductor L1 are used by both converter circuits, the output capacitor C2 and diode D1 serve both circuits' output stages. This multi-functionality reduces the total component count and simplifies the overall device structure.
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
The hybrid design achieves both high efficiency (>85% in normal operation) and cold-start capability without increasing the footprint or bill of materials, enabling plug-and-forget operation for IoT and WSN devices.
Implementation Method 1
a first DC-DC converter circuit (10) arranged for converting said low-voltage input to a first higher-voltage output during a start-up mode of the system
Implementation Method 2
a second DC-DC converter circuit (20) arranged for converting said low-voltage input to a second higher-voltage output during an normal operational mode
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present invention relates to an electrical power energy converter unit for converting Direct Current to Direct Current, DC-DC, with improved efficiency and cold-start capability. In an aspect there is provided a Direct Current to Direct Current, DC-DC, converter for converting a low-voltage input to a higher-voltage output according to a conversion factor for powering a load such as a wireless sensor node, the converter comprising: a first DC-DC converter circuit arranged for converting the low-voltage input to a first higher-voltage output during a start-up mode of the load; a second DC-DC converter circuit arranged for converting the low-voltage input to a second higher-voltage output during an normal operational mode of the load; a control circuit for control of the conversion factor; wherein each of the first and second converter circuit comprises: an input stage for receiving the low-voltage input; an intermediate stage in series with the input stage for converting the low-voltage input to the first higher-voltage or second higher-voltage output circuit at a conversion factor being defined by the ratio between the input and output; a final stage in series with the intermediate stage for outputting the first higher-voltage or the second higher-voltage output; wherein each of the stages comprises: a shared capacitor for boosting voltage of said low-voltage input to said first higher-voltage output of said first converter or to said second higher-voltage output of said second converter.