Dual-Folded Bootstrap Buck-Boost Converter for High-Frequency Charging
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Solution Overview
Problem
External MOSFET-based charger designs suffer from lower efficiency and higher thermal losses, which consume thermal budget that could be used for performance gain on System-on-Chip (SoC) during AC-power mode, and require reduced frequency operation, leading to larger size and increased real estate.
Innovation Solution
A buck-boost converter design using DrMOS or DrGaN devices with dual-folded bootstrap capacitors, which allows for higher frequency operation, reduced parasitic losses, and optimized packaging, enabling smaller inductor size and lower real estate requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If external MOSFET-based charger designs are used, then the device can be implemented with conventional components, but the efficiency is lower and thermal losses are higher
Solution Approach 1:
The patent integrates the driver and MOSFET into a single DrMOS device package, merging previously separate components. This integration reduces parasitic inductance and resistance, leading to lower conduction losses and improved efficiency while maintaining ease of implementation through a unified component structure
Solution Approach 2:
The driver circuit is nested within the DrMOS device package, with the driver internally coupled to the MOSFET. This nested configuration allows the driver to be physically close to the power switch, minimizing trace inductance and improving overall device efficiency by reducing energy losses in the connection paths
2Speed
If external MOSFET-based charger designs are used, then the implementation is straightforward with conventional components, but the frequency of operation must be reduced to keep efficiency high
Solution Approach 1:
By merging the driver and MOSFET into a single integrated DrMOS device, the patent eliminates the parasitic inductance of external connections. This allows the device to operate at higher switching frequencies without the efficiency penalties that would normally accompany increased frequency in conventional designs
Solution Approach 2:
The patent replaces the mechanical/physical separation of driver and MOSFET components with an integrated electronic solution. The internal coupling within the DrMOS device substitutes for external PCB traces and connectors, enabling higher frequency operation by eliminating the physical limitations of discrete component layouts
3Area of stationary object
If the frequency of operation is reduced to keep efficiency high, then thermal losses are managed, but the real-estate and z-height increase
Solution Approach 1:
The integration of driver and MOSFET into a single DrMOS device dramatically reduces the footprint required on the PCB. The merged component eliminates the need for separate driver ICs, MOSFET packages, and extensive interconnecting traces, thereby reducing both planar real-estate and z-height while allowing higher frequency operation that further shrinks passive component sizes
Solution Approach 2:
The patent transitions from a distributed three-component layout (driver, MOSFET, inductor) to a compact integrated structure. By consolidating the driver and MOSFET into one device package, the solution reduces the spatial dimensions required, allowing for smaller overall charger design with reduced z-height and improved thermal management
4Loss of energy
If DrMOS devices with dual-folded bootstrap are used, then efficiency is higher and thermal losses are lower, but the device structure becomes more complex
Solution Approach 1:
The dual-folded bootstrap capacitor configuration segments the charging paths for the high-side MOSFET gate. By creating separate folded paths that connect to different inductor nodes, the design ensures proper gate drive voltage generation during both buck and boost operations, improving efficiency through optimized switching while managing the structural complexity through systematic segmentation of the bootstrap network
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 design achieves higher efficiency, lower thermal losses, and reduced size, allowing for improved SoC performance within the same thermal budget, enabling thinner and lighter systems with fast-charging capabilities and flexibility using USB Type-C compliant power supply.
Implementation Method 1
dual-folded bootstrap capacitors coupled to the inductor, the first driver and the second driver
Implementation Method 2
an inductor coupled to the first module and the second module
Implementation Method 3
reduced parasitic losses, and optimized packaging
Data Source
AI summary
A buck-boost converter having dual-folded bootstrap for driver metal oxide semiconductor (DrMOS) device that, in addition to the traditional bootstrap capacitors, include folded bootstrap capacitors that cross-couple inductor nodes to the two sets of DrMOS switches. The DrMOS switches can be n-type or p-type, and can be replaced with driver Gallium Nitride (DrGaN) devices.