Battery Charger Digital Charge Reduction Loop
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Solution Overview
Problem
Traditional USB battery chargers are limited to selecting only two charging currents (500 milliamps or 100 milliamps), leading to inefficient charging times and potential system core starvation due to inconsistent USB port power delivery capabilities.
Innovation Solution
A battery charger apparatus with a digital charge reduction loop that dynamically adjusts charge current based on the source voltage, using a charge-current control circuit, analog control circuit, digital counter, and digital-to-analog converter to optimize charge current usage, allowing for step-wise adjustments to prevent source voltage drops and ensure efficient charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional charge-current regulation uses two current sense resistors to monitor charge current, then the battery charging is prevented from drawing excessive current, but the battery charger can select only from one of two charging currents (500 milliamps or 100 milliamps), resulting in long charging times and inability to utilize intermediate power capabilities
Solution Approach 1:
The patent implements a digital charge reduction loop that dynamically adjusts the charge current parameter based on detected USB port power delivery capability. The system monitors the USB port's current delivery ability and continuously modifies the charge current level, enabling selection of any current value between 100mA and 500mA rather than being restricted to fixed discrete levels. This resolves the contradiction by allowing the system to maintain reliable current regulation while achieving optimal charging speed through continuous parameter adjustment.
Solution Approach 2:
The patent transforms the static, fixed charge current selection into a dynamic system that automatically adapts to USB port capabilities. The digital charge reduction loop continuously monitors power delivery conditions and adjusts charge current in real-time, enabling the battery charger to optimize charging speed based on available power while preventing excessive current draw. This dynamic approach resolves the contradiction between reliable current control and charging efficiency.
2Device complexity
If traditional charge-current regulation operates at fixed current levels, then the system is simple to implement, but it unnecessarily slows the charging process when USB hosts can supply more than 100 milliamps but less than 500 milliamps
Solution Approach 1:
The patent introduces a digital charge reduction loop that provides continuous feedback between the USB port power delivery detection and charge current control. The system monitors the USB port's current delivery capability and feeds this information back to dynamically adjust the charge current level. This feedback mechanism enables the system to optimize charging time by utilizing the actual power capabilities of the USB host, resolving the contradiction between simple circuit implementation and charging speed optimization.
3Productivity
If USB device draws maximum charge current to reduce charging time, then charging speed is improved, but the system core may be starved of power causing operational issues
Solution Approach 1:
The patent implements a dynamic charge current adjustment system that continuously monitors USB port power delivery capability and adjusts charge current accordingly. By detecting the actual power available from the USB host, the system determines the maximum safe charge current that will not cause system core starvation. This dynamic control resolves the contradiction by enabling fast charging when power is available while preventing system instability when power is limited.
Solution Approach 2:
The digital charge reduction loop provides continuous feedback monitoring of USB port power delivery conditions. Based on this feedback, the system automatically adjusts charge current to levels that maximize charging speed without compromising system core operation. This feedback-based control resolves the contradiction between charging speed and system reliability by enabling real-time optimization of power allocation.
Data Source
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AI summary
A battery charger apparatus for charging a battery, comprises a charge-current control circuit for receiving a charge-current control signal to control an amount of charge current being drawn from an input source; an analog control circuit for generating an analog control signal representative of a maximum charge current used to charge a battery; a digital charge reduction loop including a circuit determining a charge-current adjustment signal; a counter generating a digital count value based on the charge-current adjustment signal; and a digital-to analog converter generating a control signal based on the digital count value, the control signal representing a reduced amount of charge current used to charge the battery; and a switching mechanism selecting one of the analog control signal or the control signal based on the source voltage, the selected control signal being used as the charge-current control signal to the charge-current control circuit.