Converter Overcurrent Protection Switch Voltage Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Forward type low voltage DC-DC converters in green cars require expensive current sensors to detect high output currents, increasing manufacturing costs, and fly-back type converters have different control schemes that further elevate costs due to added circuits.
Innovation Solution
A converter system that calculates output current using comparators installed across an overcurrent protection switch at the primary side of a transformer, eliminating the need for expensive current sensors by detecting voltage and converting it into an output current sensing value, which is then compared with a reference value to control the overcurrent protection switch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a current sensor is used to detect output current directly, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent uses an overcurrent protection switch as an intermediary element. Instead of directly measuring output current with a sensor, the system measures voltage across the protection switch, which serves as a mediator to indirectly obtain current information through the transformer turns ratio relationship, thereby avoiding direct current sensor installation
Solution Approach 2:
The patent replaces the mechanical/electrical current sensing system with a voltage measurement system. By measuring voltage across the protection switch and using the transformer turns ratio, the system substitutes direct current measurement with voltage measurement and calculation, simplifying the hardware requirements
2Reliability
If a fly-back type DC-DC converter is used, then overcurrent protection is improved, but device complexity increases due to added circuits
Solution Approach 1:
The overcurrent protection switch serves multiple functions: it provides overcurrent protection, enables current sensing through voltage measurement, and works with the comparator to implement control logic. This multi-functionality eliminates the need for separate protection circuits while maintaining reliability
Solution Approach 2:
The patent merges the overcurrent protection function with the current sensing function into a single integrated approach. The protection switch and comparator work together as a unified system rather than separate components, reducing overall device complexity while maintaining protection capability
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
This approach allows for secure current sensing performance comparable to traditional methods without using expensive current sensors, reducing costs and energy losses while improving EMI characteristics.
Implementation Method 1
a comparator configured to detect a voltage of the overcurrent protection switch to convert the detected voltage into an output current sensing value
Data Source
AI summary
A converter may include a transformer, an overcurrent protection switch configured to be installed at a primary side of the transformer to prevent an overcurrent, a comparator configured to detect a voltage of the overcurrent protection switch to convert the detected voltage into an output current sensing value and compare the output current sensing value with a reference value, and a protection controller configured to normally operate or forcibly turn off the overcurrent protection switch depending on a comparison result of the comparator.