DC Output Circuit Topology for Lightning Protection and Power Cutoff
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Solution Overview
Problem
Conventional direct current output circuits for communication base stations face high costs and inefficiencies due to the use of high-current bidirectional TVS transistors and large, complex relay systems, which fail to meet market requirements for low costs and high efficiency, and require additional components for lightning protection.
Innovation Solution
A direct current output circuit utilizing a semiconductor switch, decoupling inductor, and two diodes in parallel configurations for each branch, with a current sampling element to detect and manage overcurrent, providing overvoltage and overcurrent protection while reducing costs and volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a high-current bidirectional TVS transistor is used for lightning protection, then lightning protection capability is improved, but cost increases and residual voltage reaches about 130 V
Solution Approach 1:
The patent introduces a TVS transistor as an intermediary protection component connected in parallel with the load, which clamps voltage spikes during lightning strikes and protects the semiconductor switch without requiring the switch itself to have high voltage withstand capability. This mediator absorbs the harmful voltage transients while maintaining low residual voltage in the main circuit.
Solution Approach 2:
The protection function is segmented into two parts: the semiconductor switch handles normal power switching operations, while the TVS transistor specifically handles lightning protection. This division allows each component to be optimized for its specific function, reducing overall system cost and improving performance.
2Ease of operation
If a MOS transistor with 150 V withstand voltage is used as semiconductor switch, then power-off control function is achieved, but turn-on impedance is large and efficiency decreases
Solution Approach 1:
The patent changes the voltage parameter of the semiconductor switch from 150 V to a lower voltage rating (e.g., 30 V or 60 V), which dramatically reduces turn-on impedance and improves efficiency. The TVS transistor compensates for the lower voltage rating by providing overvoltage protection, allowing the use of more efficient low-voltage switches.
3Reliability
If a high-capacity contactor with arc extinguishing apparatus is used, then reliability is improved, but size and cost increase
Solution Approach 1:
The patent replaces the mechanical contactor with a solid-state semiconductor switch, eliminating the need for mechanical arc extinguishing apparatus. The semiconductor switch achieves reliable switching through electronic control, and the TVS transistor provides protection against voltage spikes, substituting mechanical protection mechanisms with solid-state alternatives.
4Ease of operation
If a combination of direct current relay and semiconductor switch is used, then power-off control is achieved, but control complexity increases due to soft turn-on and soft turn-off requirements
Solution Approach 1:
The patent extracts the protection function from the control system by adding a parallel TVS transistor, which automatically clamps voltage spikes without requiring complex control logic. This allows the semiconductor switch to operate with simple on/off control, removing the need for complex soft turn-on and soft turn-off sequences.
5Object-affected harmful factors
If additional protection components such as pressure-sensitive components are added for lightning protection, then lightning protection capability is improved, but overall cost increases
Solution Approach 1:
The TVS transistor serves multiple functions: it protects against lightning strikes, clamps voltage spikes during switching operations, and protects the semiconductor switch from overvoltage conditions. This multi-functionality eliminates the need for separate pressure-sensitive components or other dedicated protection devices, reducing overall system cost.
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 circuit effectively manages power-off control and lightning protection, reducing costs and volume by utilizing diodes and inductors to suppress lightning current, and lowering the requirements for semiconductor switch specifications.
Implementation Method 1
a decoupling inductor (170), where the decoupling inductor (170) and the semiconductor switch (140) are connected in series between the negative electrode of the power supply (110) and the negative port (190)
Implementation Method 2
a first diode (150), where a positive electrode of the first diode (150) is connected to the negative electrode of the power supply, a negative electrode of the first diode (150) is connected to the negative port (190)
Data Source
Figure 1~2
Figure 3~4
AI summary
This application provides a direct current output circuit, including: a power supply, which outputs a direct current; power supply ports, which supply power to a load circuit, and include a positive port and a negative port; a semiconductor switch, which is connected between a negative electrode of the power supply and the negative port, and is configured to switch on and off of the load circuit; a decoupling inductor, where the decoupling inductor and the semiconductor switch are connected in series between the negative electrode of the power supply and the negative port; a first diode, where a positive electrode of the first diode is connected to the negative electrode of the power supply, a negative electrode of the first diode is connected to the negative port, and the first diode is connected in parallel to the semiconductor switch and the decoupling inductor; and a second diode, where a positive electrode of the second diode is connected to the negative port, a negative electrode of the second diode is connected to the positive port, and the second diode is connected in parallel to the load circuit. The direct current output circuit can meet requirements for power-off control and lightning protection, and can reduce costs.