DC-DC Converter Current Sensing for High-Load Overload Control
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Solution Overview
Problem
Existing DC-to-DC converters face challenges in reliably sensing and controlling current during high load events, as inline resistive sensors and Hall effect sensors are prone to overload, complex to implement, and inefficient, especially when dealing with shorted output or high current overloads.
Innovation Solution
The use of two current sense transformers, one connected in series with a primary switch and the other in series with a recirculating switch, allows for accurate measurement of current at specific locations, enabling an estimated output current calculation and improved control through a switching controller, which is more reliable and efficient than traditional sensing methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If inline resistive sensors or Hall effect sensors are used for current sensing, then current measurement can be achieved, but the system becomes complex, prone to overload, and inefficient during high load events
Solution Approach 1:
The patent replaces traditional resistive or Hall effect current sensors with current sense transformers that utilize electromagnetic induction. This substitution eliminates the need for complex support circuitry and power requirements while providing galvanic isolation and improved reliability during high load events. The transformers sense current through magnetic coupling without direct electrical contact, thereby simplifying the overall sensing system architecture.
Solution Approach 2:
The current sense transformers act as intermediary devices that provide galvanic isolation between the primary current circuit and the control circuitry. By using magnetic coupling as an intermediary mechanism, the system achieves accurate current sensing without direct electrical connection, thereby preventing overload issues and reducing complexity of the sensing network.
2Measurement precision
If traditional current sensors are used, then current measurement is possible, but additional power and complex support circuitry are required
Solution Approach 1:
The current sense transformers are passive devices that derive their operating energy from the magnetic field generated by the current being measured. They do not require external power supplies or active components, thereby eliminating additional power consumption and the need for complex support circuitry. The transformers self-generate the necessary signals through electromagnetic induction from the primary current.
3Device complexity
If single current sensor is used, then simple implementation is possible, but reliable current sensing during high load events cannot be achieved
Solution Approach 1:
The patent employs multiple current sense transformers positioned at different locations in the circuit to measure current in different branches. By segmenting the current measurement function across multiple transformers, the system achieves comprehensive and reliable current monitoring during high load events, while each individual transformer remains a simple and robust device.
Solution Approach 2:
The patent utilizes the different current parameters (magnitude, phase) measured by multiple transformers to detect and respond to high load conditions. By monitoring changes in these electrical parameters across different circuit branches, the system reliably detects overload conditions and can implement protective control actions.
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 solution provides reliable and efficient current sensing and control, preventing overload and improving the overall efficiency of the DC-to-DC converter by using galvanically isolated, passive current sense transformers that do not require additional power or complex support circuitry.
Implementation Method 1
a first current sense transformer connected in series the first switch, a second current sense transformer connected in series with the second switch
Data Source
AI summary
Example DC-to-DC converters are described herein. An example DC-to-DC converter includes an input connected in series with an output. The input is to be connected to a voltage source and the output is to be connected to a load. The DC-to-DC converter also includes a first switch connected in series with the input and the output, a second switch connected in parallel with the output, a first current sense transformer connected in series the first switch, a second current sense transformer connected in series with the second switch, and a switching controller to determine an estimated output current at the output based on the measurements from the first and second current sense transformers.