Charging Circuit Modulates Current via Open Circuit Voltage
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Solution Overview
Problem
Existing methods for charging small battery-operated appliances are limited to specific power supplies, leading to potential overloading when using different power sources.
Innovation Solution
A charging method that determines the open circuit voltage of a power supply and modulates the charging current using a pulse duty factor, allowing the appliance to be charged safely with various power supplies by controlling a switch or controllable resistor based on the power supply's maximum output power and the appliance's power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a power supply is adapted to a specific appliance's operating voltage and current consumption, then the appliance is fed with the correct voltage and the power supply is not overloaded, but the appliance cannot be charged with different power supplies
Solution Approach 1:
The charging circuit dynamically adjusts the pulse duty factor based on the detected open circuit voltage of the connected power supply. This dynamic adaptation allows the circuit to optimize charging parameters in real-time according to the specific power supply characteristics, enabling compatibility with different power supplies while preventing overloading conditions
Solution Approach 2:
The system changes the charging current parameters by modulating the pulse duty factor according to the detected power supply characteristics. By varying the duty cycle based on the open circuit voltage, the charging circuit adapts its operating parameters to match the capabilities of different power supplies, achieving both versatility and safety
2Productivity
If the charging current is increased to reduce charging time, then productivity improves, but the power supply may be overloaded
Solution Approach 1:
The charging circuit uses periodic pulse-width modulation to deliver charging current. By varying the pulse duty factor within the periodic cycle, the system achieves effective charging current control that prevents continuous overloading while maintaining high average charging power for improved charging speed
Solution Approach 2:
The pulse-width modulation technique maintains continuous useful action by ensuring that charging current is delivered throughout the charging process through repeated pulses. The optimized duty factor ensures maximum power transfer within safety limits, achieving both high productivity and power supply protection
Data Source
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AI summary
The present invention relates to a method for charging a battery by means of a power supply and also relates to a small, battery-operated electrical appliance and a charging circuit for the small electrical appliance. The method has the following steps: determining the open circuit voltage of the power supply; assigning the determined open circuit voltage of the power supply to a pulse duty factor or modulation factor; and modulating the charging current delivered by the power supply by using this pulse duty factor or modulation factor so that the average power delivered by the power supply does not exceed the maximum allowable output power of the power supply. This assumes that different power supplies differ in terms of their open circuit voltage and maximum output power, wherein power supplies with the same open circuit voltage also have the same maximum output power, so that the power supply's maximum output power can be determined by means of the open circuit voltage. The charging circuit is equipped to carry out this method. A small electrical appliance with such a charging circuit can be charged with different power supplies, namely also with power supplies that would normally overload when charging such small electrical appliance.