Power Management Circuit for Load-Specific Voltage Selection
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Solution Overview
Problem
Current battery charging systems for portable devices inefficiently utilize higher voltage power sources, leading to battery discharge rather than charging, and fail to properly manage system loads, resulting in unnecessary battery power depletion.
Innovation Solution
A battery charging and power management circuit that utilizes a topology with a diode or transistor switch to select the maximum available voltage source, separating system loads into constant power and constant current components, and coupling switching regulators to the maximum voltage bus while linear regulators are directly connected to the battery, allowing efficient use of external power sources to charge the battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If power from a higher voltage source is not properly utilized, then the battery discharge instead of being charged, but the system fails to efficiently use available power sources
Solution Approach 1:
The system dynamically selects between different power sources (battery, USB, wall adapter) based on voltage levels and load conditions. The power management circuit continuously monitors voltage sources and automatically switches between them, allowing the system to adapt to available power sources and optimize charging efficiency while preventing battery discharge.
2Use of energy by moving object
If the load of the system is not being properly distinguished and managed, then unnecessary discharge of the battery power occurs, but the system lacks proper load management
Solution Approach 1:
The system segments loads into constant power loads and constant current loads, allowing different power management strategies for each type. Constant power loads are managed based on available voltage sources, while constant current loads are managed based on current capacity. This segmentation enables precise control over power distribution and prevents unnecessary battery discharge.
Solution Approach 2:
The system changes operational parameters (voltage, current) based on the type of load and available power sources. By detecting load characteristics and adjusting power delivery parameters accordingly, the system optimizes power consumption efficiency and prevents battery power depletion while meeting the specific requirements of different load types.
3Device complexity
If a simple charger topology is used, then the device complexity is reduced, but the higher voltage power source is not properly utilized
Solution Approach 1:
The power management circuit is designed to universally support multiple power sources (battery, USB port, wall adapter) and multiple load types (constant power, constant current). This multi-functional approach allows the system to properly utilize higher voltage power sources when available while maintaining a relatively simple overall topology that can handle various charging scenarios without requiring complex dedicated circuits for each power source.
Data Source
AI summary
Traditionally, system loads are placed in parallel with the battery. This simple topology wastes the available power if the USB power and/or wall adapter is present. Recent topologies have made some improvements by powering the load by the maximum available voltage. Thus, if a USB power source or wall adapter is present, the load is powered by them rather than the battery, thus improving the system efficiency. However, since the USB power and wall adapter power are current limited, if the load requires higher current than the current limited USB or adapter, then the entire system is powered at voltage of the battery. The present invention further improves the system efficiency by distinguishing the load and powering the constant power loads by the maximum voltage and placing the constant current loads in parallel with the battery.