ST recently updated its high temperature transistor product line, with a node temperature to reach 150oC, providing anti-high noise function. The TN series encompasses a variety of pill currents from 12a to 80a. This article will focus on a special equipment: TN5015H-6G. The device is the first 50 A of the gear current and a device of 600 V, can it solve more problems?
How do we protect circuits in household appliances, industrial systems and motorcycle regulators? Recently, ST recently updated its high temperature transistor product line, and the node temperature can reach 150oC, providing anti-high noise function. The TN series encompasses a variety of pill currents from 12a to 80a. This article will focus on a special equipment: TN5015H-6G. The device is the first 50 A of the gear current and a device of 600 V, can it solve more problems?
First introduce several knowledge points:
Semiconductor gate flow pipe?
The semiconductor gate flow tube is a solid-state semiconductor device and is called thyristor. It creates three PN junction layers by alternating P-class and T-type substances (PNPN). A semiconductor gate flow tube typically has three electrodes: an anode, a cathode and a door (control electrode).
Left is one-way thyristor, right is two-way thyristor
The most common semiconductor gates is a silicon control rectifier (SCR). When the cathode is negative relative to the anode, there is only a current when the pulse is added to the door. The SCR then begins to conduct electrically, until the voltage between the cathode and the anode is inverted or lowered to the limit value. Using this semiconductor gate flow tube, only a small trigger current or voltage can be used to exchange or control a large amount of electric power.
What is the surge?
The so-called surge is also known as surges, and the surge refers to the peak of the instant, including surge voltage and surge current. Surge of power supply systems mainly come from two reasons: external (reasons for lightning) and internal (electrical equipment start and stop, etc.). The characteristics of surges are often very short. The overvoltage caused by lightning is often in the micro-second level, the overvoltage caused by electrical equipment is often in milliseconds, but the instantaneous voltage and current are extremely large, and it is very likely to use electricity equipment and The cable is harmful, so the surge protector is required to protect them.
Among them, the surge protector, the so-called lightning protection device, which is commonly used in electronic devices and instruments. When the electrical equipment is interfering with the highest current or by lightning strikes, the surge protector can pass through the shunt, and quickly vent the current into the earth, and protect the equipment from lightning strikes.
Pay attention to its size when purchasing a leakage protector. Usually the leakage protector is divided into rated and action currents. Among them, the rated current is divided into 10A, 16A, 20A, and 30 mA, 10 mA, and 100mA, etc., and the like. If the household current is 6, the rated 20A, D type leakage protector can be selected.
TN5015H-6G
This requires engineers to reassess, thinking about how to prevent the incurns from demanding requirements.
When engineers want to increase profitability and product differentiation, many people choose to improve design stability. Users also expect their products to withstand increasingly harsh environments, especially in high-end or small markets. One way to make products more robust is to improve overvoltage protection. In fact, as a brand, there are few more damage to the brand than that fail to prevent prices. For example, this is unacceptable due to the unreliable damaged television, or damaged industrial products due to the impact of the weather. Therefore, as robustness is increasing, surge protection has become increasingly critical.
Currently, most certifications are presed for surges between 2kV to 4kV depending on the application. Although these values reflect most cases, many people think they are not enough, especially for industrial or high-end design. Therefore, engineers have more and more developed surge protection circuits between 6kv to 12kV. Some regulators have begun to re-assess their standards to take into account this new reality. The problem is that today's companies need solutions because designers are trying to formulate plans to be more extreme extreme conditions.
Thyristor control MOV leakage
Once people start talking about surge protection, many engineers began considering metal oxide resistors (MOV). The main purpose of MOV is to absorb huge voltage surges to prevent other parts of the system. In its most basic form of expression, MOV uses many diodes and load parallel. Under normal working conditions, MOV has high corrosion resistance. However, if a high transient voltage suddenly occurs, the resistance of the diode drops to almost zero, so that the surge is transferred from the primary device. Therefore, this is an effective way to protect sensitive components from sudden surgery.
Engineers seek to establish a more robust product, they often try to solve the inherent shortcomings of MOV. In fact, the performance of MOV will decline over time or multiple times, it will become less tube after a period of time. The reason is that the leak current of MOV will increase after each surge or timeout. In order to solve this problem, engineers use the string of thyristors as the barrier of MOV leakage current. Since some criteria will try to limit the impact of the product on the environment, the short-lived MOV is no longer an ideal choice. Therefore, engineers must use a thyristor to ensure that their surge is more lasting. These trends explain why more and more engineers are using TN5015H-6G.
TN5015H-6G: Facing new challenges
Measuring robustness (Di / DT and DV / DT)
Engineers hope that the thyristor can improve the robustness of its surge protection, and how to determine the size of the assembly is critical. Unfortunately, some teams may be difficult to determine which technical specifications should be given priority. Therefore, it is necessary to understand that there are two parameters worth noting in countless data points:
Di / dt
DV / DT
The former measures the maximum change in current from the shutdown state to the interworking state. Briefly, it represents the current that the equipment can withstand over time, it will directly affect the system managed by the system. For example, TN5015H-6G Di / DT 100 A / 100 μs ensures that it can process 6 kV surge test.
Another value that can help engineers determine that the device size is DV / DT. This specification is measured to make the minimum voltage change rate started. This value is very important because low DV / DT means that the device will open when inappropriate. Therefore, the difficulties of engineers lies in finding a device having a sufficiently low gate trigger current (IGT), which can be openedly sensitively opened when the surge occurs, but the DV / DT is sufficient to resist noise and prevent accidental trigger. In a 150oC environment, IGT = 15 mA, DV / DT = 500 V / μs, so TN5015H-6G becomes ideal for many engineers to create better overload protection.
Higher node temperature is the key
Thanks to the 15 mA tuning door of TN5015H-6G, it can be used as a rapid trigger of the surge voltage slope and focus on SCR protection. In the case of up to 150 ° C, its low gate current and high waves current rating are a unique feature in the market. Since ST improves its manufacturing process, a higher junction temperature can be obtained. In addition, ST adds photolithography accuracy, which is more conventional 125oC, and ST has been able to design a crystal gate flow tube operating at high temperatures. This also illustrates why ST can release the TN device for automotive industry certification.
Further reading: The structure of the leakage protector
The leakage protector is mainly composed of three parts: detecting elements, intermediate zoom, operational institutions.
1 detection element. Composed of zero-sequence transformers, detecting leakage currents, and signals.
2 Enlarge the link. The weak leakage signal is enlarged, and the electromagnetic protector phase electronic protector is constituted by different means (magnifying parts can be used as an electronic device).
3 Executive agency. After receiving the signal, the main switch is converted from the closed position to the off position, thereby cutting off the power supply, is a trip member that is protected from the grid from the grid.
The role of the thyristor in the leakage protector
When the electrical equipment is leakage, there are two anomalies:
First, the balance of the three-phase current is destroyed, and the zero-order current is displayed.
Second, when normal, the metal housing that does not charge is in the ground (normally, the metal housing and the large land are zero potential).
Working principle of leakage protector:
The current normal atmosphere of the zero sequence current transformer B initial L1, L2 (two-wire and the 3 to 5) is zero, and when the protected line is electroracted or the device is leakage, the remaining current will occur. , The L3 (hundreds of hi) is in the middle of a hundred millivolts of leakage signals, and the series resonance circuit consisting of L3, C1 is greater than 800mV, and the single-to-line thyristor SCR is turned directly (the operating voltage of the SCR is 220V VD1 ~ VD4 bridge rectified supply), equivalent to the two points of A, B, almost all of the 220V alternating current is added to the trip unit T, and T is actually an electromagnet, thereby sucking the free trip mechanical device. Make the movement, the static contact, cut off the power, thereby serving as a leakage (electric shock) protection. The trip-free product is large, the rated action time is slightly faster, and the trip (trip) is rapid, and Liso.
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