Single Inductor Multi-Output DC-DC Converter Time Sharing
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Solution Overview
Problem
Conventional buck and boost converters require dedicated inductors, which are expensive and occupy valuable circuit board space, especially in applications needing multiple regulated DC voltages from a common power source.
Innovation Solution
A power management unit that uses a single inductive element time-shared by both step-down and step-up power converters, controlled by a finite state machine to efficiently generate multiple voltage outputs, reducing the need for multiple inductors and optimizing circuit board space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dedicated inductors are used for each buck and boost converter, then the converters can operate independently and reliably, but the circuit board space occupation and component cost increase significantly
Solution Approach 1:
The patent merges multiple inductor functions into a single shared inductor that serves both the buck converter and boost converter. The inductor is physically shared between the two converters, with switching mechanisms that direct current flow appropriately. This combining approach reduces the total component count and circuit board space occupation while maintaining the functional independence of each converter through controlled switching.
Solution Approach 2:
The single inductor is designed to perform multiple functions: it serves as the energy storage element for both the buck converter (step-down) and boost converter (step-up). The inductor can operate in different modes depending on the switching state, providing universal functionality across multiple power conversion paths. This multi-functionality eliminates the need for separate dedicated inductors for each converter.
2Reliability
If multiple dedicated inductors are used, then each converter has dedicated energy storage, but the component cost and device complexity increase
Solution Approach 1:
The patent combines the energy storage function of multiple inductors into a single shared inductor. The inductor is physically shared between the buck and boost converters, with the understanding that at any given time, it serves one converter or the other through switching control. This merging reduces component count and structural complexity while maintaining adequate energy storage capability for both converters through proper switching management.
Solution Approach 2:
The system uses periodic switching actions to allocate the shared inductor to different converters in turn. The switching mechanism periodically directs the inductor to serve the buck converter during buck operation and the boost converter during boost operation. This periodic allocation ensures that each converter receives dedicated energy storage service when needed, while the overall system maintains lower complexity through the shared inductor architecture.
3Area of stationary object
If a single shared inductor is used, then circuit board space and component cost are reduced, but the control complexity and potential interference between converters increase
Solution Approach 1:
The patent incorporates feedback mechanisms that monitor the operating state of both the buck and boost converters. This feedback information is used by the switching control logic to determine when to allocate the shared inductor to each converter. The feedback ensures that the inductor is properly directed based on actual operational needs, preventing conflicts and interference while managing the control complexity through intelligent decision-making based on system state.
Solution Approach 2:
The switching mechanism acts as an intermediary between the shared inductor and the two converters. This intermediary component manages the connection and disconnection of the inductor to appropriate converters, isolating them from each other when not in use. The switching intermediary prevents direct interference between the buck and boost converter circuits while enabling the inductor to serve both functions sequentially, thus reducing control complexity compared to direct coupling.
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 solution enables efficient power management with reduced component costs and space usage, improving power efficiency and reducing power consumption in devices like cellular communication devices and battery-powered tracking devices.
Implementation Method 1
an inductive element connected to the step-down power converter and the at least one step-up power converter and configured to store energy and selectively release the stored energy
Data Source
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AI summary
A power management unit (400) includes: a step-down power converter (402) configured to receive a first voltage (Vin) and output a second voltage, wherein the second voltage is less than the first voltage and at least one step-up power converter (416) configured to receive the second voltage and output a third voltage, wherein the third voltage is greater than the second voltage. It also includes an inductive element (410) connected to the step-down power converter and the at least one step-up power converter and configured to store energy and selectively release the stored energy, wherein the inductive element is time shared by both the step-down power converter and the at least one step-up power converter; and a finite state machine (FSM) configured to control the time sharing of the inductive element.