The diode is the most basic semiconductor device and is often used in many electronic designs, such as voltagers, converters, reversers, circuit protection, pressurers, etc. The three most common types of diodes are whole-stream diodes (general diodes), zina diodes and shortki diodes. There is, however, another special diode called the tvs diode, which plays a crucial role in the processing of transient peaks in electrically designed circuits. This paper will further explore transient voltage inhibitors and why they need your circuits。
What does transient mean
An instantaneous state is the short peak of a voltage or current and may damage the circuit in a number of ways. Some transients occur only once, while others may recur. These transient voltages range from millimetres to thousands of volts, lasting from nanoseconds to hundreds of milliseconds。
What's the reason for the sudden changes in the circuit
The transient may be caused by internal or external connections in the circuit. For example, transients may be generated internally by the failure point of a sensor load switch or switch and connector. Externals may be generated by lightning strikes or sensor switches。
Transient voltage containor (tvs)
The transient voltage repressor (tvs) is a protective device designed to protect your circuits from surges in voltage or currents. The main way to protect circuits from overpressure is to connect these tvs equipment to the circuit。
Type of transient voltage suppressor
There are many types of tvs devices that can be used for transient voltage suppression, including metal oxidation sensitivity resistance, tvs diode, zina diode or sidecarrying. In the case of the asm (assem) brand tvs diode, the product line covers the protection needs of transient voltage protection from low-capacity esd series (e. G. Esd12a005ta, esd5d007ta) to high-power vehicle-level series (e. G. Sm8s66j26v, smc15j40b)。
According to the working principles, transient voltage inhibitors can be divided into two categories: tight and crowbar. The pliers limit the voltage to fixed levels, absorbing excess energy generated by the voltage event in the process, and the tvs diode is a typical example of a tightening device。
On the other hand, once the crowbar device triggers the line of protection, excess energy will be diverted from protected circuits. When it is detected that the voltage (twice peak) will be triggered, the crowbar will be short-circuited, thereby reducing the circuit's voltage; after a period of time, when the crowbar will be unlocked, the circuit's voltage will rise back to a stable state and the circuit will return to normal operation。
Instant voltage inhibition diode - tvs diode
The transient voltage inhibition diode is a solid pn-lycÉe designed to offset the sudden or instantaneous voltage effects of sensitive semiconductors and circuits. It is a holding device that absorbs excess energy from a voltage event when the sensor voltage exceeds the avalanche through the voltage, and then automatically resets it after it has disappeared. While the standard diodes and the zina diodes are also used for voltage/transient protection, they are not as strong as the tvs diodes because the standard and the zina diodes are designed for current and voltage regulation。
Tvs diode type
The transient voltage inhibition diodes can be divided into one-way and two-way。
A one-way transient voltage inhibition of the diodes as the integrator of a positive circuit, similar to other avalanches of diodes, is able to withstand a significant peak current. The symbol is very similar to the zina diode. For example, esd12a005ta of asm is a one-way tvs diode that applies to static protection of portable equipment, while sm8s66j26v is a one-way tvs diode for the protection of vehicle circuits。
The two-way tvs diodes have the same characterization curves in a positive and negative direction, so they can work normally regardless of how they connect to the circuits, have ultra-low capacity and are suitable for the protection of high-speed data lines。
How to use the tvs diode
Tvs diodes are connected to devices or circuits to be protected. The tvs device is specifically designed to be punctured at a specific voltage level and can conduct large currents without causing damage。
Under normal voltage conditions, the tvs diodes are open, but there are weak leaks. When normal voltage exceeds a certain level, an avalanche occurs in the tvs diode, resulting in the passing of the excess voltage from the protected circuit through the tvs diode. When the pressure disappears, the device is automatically reset。
V-i feature
The one-way and two-way v-i properties of the tvs diode show the relationship between voltage and current. The two-way diodes have the same characterization curves in both positive and negative directions, so they are connected to circuits regardless of how they are connected. One-way diodes have a positive conductive voltage above negative。
Tvs diode parameters
There are many types of tvs diodes designed for specific applications in the market. Asm has a rich series of tvs diodes, ranging from esd series for portable equipment esd protection (e. G. Esd5d007ta, esd3v3a005ta) to sm8s series for vehicle electronic wave protection (e. G. Sm8s66j26v, sm8s80j36v) and universal high power tvs, such as the smc15j series, where designers can select according to the level of voltage and power needs of specific circuits. In selecting the tvs diode, the following parameters can be consulted in the data manual:
Apply
The tvs diodes are usually used for the diversion/puffing of low-energy circuits and systems, as well as for static protection in circuits. Applications of transient voltage inhibition diodes include data and signal lines, microprocessors and mos storage units, communication/direct flow power lines and telecommunications equipment. Low-capacity models such as esd5d007ta of asim are particularly suitable for esd protection for high-speed data lines and signal lines, sm8s66j26v, etc., apply to wave protection for motor electronics and ac/dc power lines, while ultra-low-capacity models such as esd3v3a005ta can be used for static protection for high-frequency signal lines。
