Capacitive Isolation Step-Down Circuit for Safe Battery Charging
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Solution Overview
Problem
Step-down circuits in electronic devices can cause safety issues when switches fail, leading to unsuitable charging voltages being applied to batteries, potentially damaging them.
Innovation Solution
A step-down circuit design that includes a switch circuit, a rectifier circuit, and an isolation circuit with capacitors, where the negative input and output terminals are grounded together, allowing for controlled voltage conversion and isolation to prevent unsafe voltage transfer, simplifying control and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a switch in the step-down circuit fails, then the circuit structure is simple, but unsafe charging voltage is directly input to the battery causing damage
Solution Approach 1:
The patent introduces an isolation circuit as an intermediary component between the switch circuit and the battery. This isolation circuit includes capacitors that electrically isolate the switch circuit from the battery, preventing direct transmission of unsafe voltages. When switch failures occur, the isolation circuit blocks harmful voltage spikes and anomalies from reaching the battery, thus protecting it while maintaining relatively simple overall circuit structure.
Solution Approach 2:
The isolation circuit with capacitors serves as a protective buffer that is预先 (in advance) positioned between the switch circuit and the battery. This buffer absorbs and isolates voltage anomalies before they can reach the battery, providing beforehand cushioning against potential damage from switch failures or voltage spikes.
2Ease of operation
If the negative input terminal and negative output terminal are grounded together, then control is simplified and cost is reduced, but voltage isolation may be compromised
Solution Approach 1:
The capacitor-based isolation circuit acts as an intermediary that maintains electrical isolation between the input and output sides while allowing the negative terminals to be grounded together. The capacitors block direct DC connection while permitting AC coupling and voltage reference sharing, thus enabling simplified control with a single ground reference without compromising the voltage isolation safety.
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
The proposed solution enhances safety by preventing unsafe voltage transfer and simplifying control, while achieving efficient voltage conversion, thereby protecting batteries and improving the reliability of the charging process.
Implementation Method 1
an isolation circuit including at least one capacitor connected to the switch in the switch circuit and the switch in the rectifier circuit
Data Source
AI summary
A step-down circuit, an electronic device, and a step-down method are disclosed. The step-down circuit includes a positive input terminal and a negative input terminal for receiving an input voltage; and a positive output terminal and a negative output terminal for outputting a target voltage. The negative input terminal and the negative output terminal are grounded together. The step-down circuit also includes a switch circuit, a rectifier circuit, an isolation circuit, and a control unit for outputting control signals to control for turning on or off a switch in the switch circuit and for turning on or off a switch in the rectifier circuit, allowing the input voltage to sequentially pass through the switch in the switch circuit, a capacitor in the isolation circuit, and the switch in the rectifier circuit to obtain a target voltage.