Multi-Path Battery Charger for Light-Load Efficiency and Sensing
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Solution Overview
Problem
Existing battery chargers operate suboptimally during light load operations due to decreased conversion efficiency and low current control accuracy, leading to inefficiencies and errors in charging.
Innovation Solution
A multi-path charger with multiple controllable current sources connected in parallel, each with its own current sensor, where the number of active current sources is adjusted based on the load to improve efficiency and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single current source is used to handle maximum power, then the device complexity is reduced, but the conversion efficiency significantly decreases at light load
Solution Approach 1:
The charger is divided into multiple independent current sources (first current source, second current source, etc.), each capable of operating independently. Each current source has its own control circuit and current sensor, allowing the system to segment the power delivery function across multiple parallel paths rather than relying on a single current source.
Solution Approach 2:
The system dynamically adjusts the number of active current sources based on the charging load requirements. The controller activates or deactivates specific current sources according to real-time power demands, enabling the charger to adapt its configuration from single-current-source mode at light load to multi-current-source mode at high load, thereby optimizing efficiency across the entire operating range.
2Power
If current sensors are dimensioned for maximum current, then they can handle peak loads, but the current measurement accuracy and precision are low at light load
Solution Approach 1:
The current measurement function is segmented across multiple sensors, each assigned to a specific current source. Each sensor is dimensioned to accurately measure the current range of its associated current source, including light load conditions. This segmentation allows each sensor to operate in its optimal measurement range rather than all sensors being oversized for maximum current.
Solution Approach 2:
Each current sensor is optimized for its local measurement context - specifically tuned to accurately measure the current output of its associated current source. This local optimization ensures that each sensor operates with high precision in its designated range, particularly at light load conditions where individual current sources operate independently.
3Power
If all current sources are activated to meet high power demand, then the maximum power delivery is achieved, but the fixed losses increase and efficiency decreases
Solution Approach 1:
The system dynamically configures the number of active current sources based on real-time power demands. At light load, only one current source is activated to minimize fixed losses from inactive components. As power demand increases, additional current sources are progressively activated. This dynamic adjustment ensures that fixed losses are minimized at each operating point while still meeting the required power delivery.
Solution Approach 2:
The system changes the operational parameters by adjusting the number of active current sources according to power demand levels. This parameter change allows the charger to transition between different operational states (single-source mode, dual-source mode, etc.), optimizing the balance between power delivery capability and fixed loss minimization across the entire operating range.
Data Source
AI summary
A multi-path charger having multiple controllable current sources connected in parallel, each current source is in series with its own current sensor, and both are dimensioned based on the maximum power and current divided by the number of the controlled current sources. The number of used current sources depends on the load. With a light load, only one current source is on while the rest is turned off. As the load increases, more current sources are switched on to supply power to the load. By that, the power efficiency and current measurement accuracy are significantly improved with a light load. Moreover, the multi-path charger can be used with multi-output with each output supplied by several parallel current sources.