How to Detect Transient Voltage Suppression Diodes

The clamping voltage of the transient voltage suppression diode is not absolutely fixed, it will vary with the current, the voltage at the initial turn-on is lower, and when the current reaches the limit value, the voltage at both ends of the diode (clamping voltage) reaches the maximum value.

When selecting the TVS tube, on the one hand, the breakdown voltage should not be too low, so as not to affect the normal operation of the system, and on the other hand, it should be ensured that the maximum clamping voltage can not exceed the limit voltage value of each component in the system, so as not to damage other components when the transient high voltage occurs.

Then it is necessary to estimate the maximum transient current value that may be reached when the transient high voltage occurs, and choose a TVS tube greater than this value to avoid protection failure caused by damage to the TVS tube.

TVS Diode Measurements:

1. Model: A series (with silver ring as the negative electrode).

2. Measurement: The black watch pen is connected to one end of the silver bar, and the red watch pen is connected to the other end. The multimeter position is either diode or beep. Normal display is 0l (infinity). Normal.

3. Model: CA series (bidirectional does not distinguish between positive and negative poles).

4. Measurement: The method is as shown in point 2. Positive and negative, negative positive, and positive and negative measurements are all 0l (infinity), which is normal.

5. If the positive and negative measurements are turned on and the value is displayed, it means that it has been damaged.

1.Use a multimeter r 1k to measure the quality of the tube. For the unipolar TVS tube, according to the method of measuring ordinary diodes, the forward and reverse resistance can be measured, the general forward resistance is about 4k5, and the reverse resistance is infinity.

2.For a bidirectional polar TVS diode, the resistance between the two pins should be infinity measured by arbitrarily changing the red and black watch pens, otherwise, the tube has poor performance or has been damaged.

Measurement and judgment of the quality of TVS transient voltage suppression diodes.

1.Use a multimeter r 1k to measure the quality of the tube.

For the unipolar TVS, according to the method of measuring ordinary diodes, the forward and reverse resistance can be measured, the general forward resistance is about 4K5, and the reverse resistance is infinity.

2.For the TVS of bidirectional polarity, the resistance between the two pins should be measured by arbitrarily changing the red and black watch pens.

is infinity, otherwise, the tube is not performing well or has been damaged.

The P6KE10CA is a bidirectional TVS transient rejection diode, so the 2 method is used.

Transient Voltage Suppressor (TVS) is a high-efficiency protection device in the form of diodes. When the two poles of the TVS diode are subjected to a reverse transient high-energy impact, it can change the high impedance between the two poles into a low impedance at a speed of 10 to the minus 12 seconds, absorb up to several kilowatts of surge power, and make the voltage clamp between the two poles at a predetermined value, effectively protecting the precision components in the electronic circuit from the damage of various surge pulses. Many friends know very little about TVS diodes, and even don't know how to buy, today Youen Semiconductor will share with you the selection skills of TVS diodes!

Transient suppression diodes.

Tips for selecting TVS diodes:

1. Determine the maximum DC or continuous working voltage of the protected circuit, the rated standard voltage of the circuit and the "high-end" tolerance.

2. The TVS rated reverse shutdown VWM should be greater than or equal to the maximum working voltage of the protected circuit. If the selected VWM is too low, the device may enter an avalanche or the normal operation of the circuit may be affected by too much reverse leakage current. Serial connection to divide voltage, parallel connection to divide current.

3. The maximum clamping voltage vc of the TVS should be less than the damaged voltage of the protected circuit.

4. Within the specified pulse duration, the maximum peak pulse power consumption PM of the TVS must be greater than the peak pulse power that may occur in the protected circuit. After the maximum clamping voltage is determined, its peak pulse current should be greater than the transient inrush current.

5. For the protection of data interface circuits, it is also necessary to pay attention to the selection of TVS devices with appropriate capacitance C.

6. Select the polarity and packaging structure of TVS according to the application. It is more reasonable to choose bipolar TVS for AC circuits; It is more advantageous to use a TVS array for multi-line protection.

7. Temperature consideration. Transient voltage suppressors can operate between 55 +150. If the TVS is required to operate at a variable temperature, the ID of its reverse leakage current increases with the increase; The power consumption decreases with the increase of the TVS junction temperature, from +25 to +175, which is about a linear decrease of about 50%, and the rain breakdown voltage VBR increases by a certain coefficient with the increase of temperature.

Therefore, it is important to consult the relevant product literature and consider the effect of temperature changes on its properties.

1) The clamping voltage of TVS should be greater than the maximum working voltage of the protected circuit 10% 20% (2) DC protection is generally unidirectional TVS, AC.

Protection is generally two-way TVSTVS arrays are available for multi-line protection.

3) The instantaneous pulse that the TVS can withstand must be non-repetitive pulses.

4) The maximum peak pulse power of the TVS must be greater than that in the protected circuit within the specified pulse duration.

The peak pulse power that may occur, the peak pulse current should be greater than the transient inrush current.

1.Introduction to TVS Diode Characteristics Why are TVS diodes in demand so high in practical applications? Understand the characteristics of TVS diodes, and the answer is right in front of you:

1) The TVS tube is produced on the basis of the voltage stabilizer tube process, and the internal chip is made of semiconductor silicon material, which is made of ,.. by semiconductor process

The steps to select a TVS are as follows:

1.Determine the DC voltage or continuous operating voltage of the circuit to be protected. In the case of alternating current, the maximum value should be calculated, i.e. the effective value*.

The reverse displacement voltage is the operating voltage (VRWM) - the VRWM of the selected TVS is equal to or greater than the operating voltage specified in step 1 above. This ensures that the current absorbed by the TVS is negligible under normal working conditions, and if the voltage specified in step 1 is higher than the VRWM of the TVS, the TVS will absorb a large amount of leakage current and be in an avalanche breakdown state, thus affecting the operation of the circuit.

3.Maximum peak pulse power: Determine the interference pulse of the circuit, and determine the TVS peak pulse power that can effectively suppress the interference according to the waveform and pulse duration of the interference pulse.

4.The maximum clamping voltage (VC) of the selected TVS should be lower than the maximum withstand voltage allowed by the protected circuit.

5.Unipolar or bipolar --- bidirectional TVS is used for alternating current or from positive and negative bidirectional pulses. TVS is also sometimes used to reduce capacitance.

If the circuit only has a forward level signal, then a one-way TVS is sufficient. The operation mode of TVS is as follows: when the forward surge, the TVS is in a reverse avalanche breakdown state; In reverse surge, the TVS acts like a forward bias diode and conducts and absorbs the surge energy.

This is not the case in low-capacitance circuits. Bidirectional TVS should be used to protect the low-capacitance components in the circuit from the damage caused by reverse surges.

6.If you know the more accurate inrush current IPP, then you can use VC to determine its power, if you can't determine the approximate range of power, generally speaking, it is better to choose a higher power.

Langtuo Electronics - the circuit protection expert by your side.

TVS Tube Selection Guide:

1) The maximum DC value, rated standard voltage value and "high-end" tolerance value of the protected circuit should be clearly confirmed;

2) The rated reverse shutdown voltage of the TVS tube should be greater than or equal to the maximum working voltage of the protected circuit.

3) The maximum clamping voltage of the TVS tube should be less than the damaged voltage of the protected circuit;

4) The maximum peak pulse power of the TVS tube must be greater than the peak pulse power of the protected circuit;

5) After determining the maximum clamping voltage of the TVS tube, its peak pulse current should be greater than the transient surge current;

6) Most of the DC protection circuits are one-way TVS tubes, AC protection circuits are mostly two-way TVS tubes, multi-channel protection circuits are TVS array devices, and high-power protection circuits are special protection modules;

7) To consider the influence of temperature change on the characteristics of TVS tube, TVS tube works between -55°C and 150°C;

8) In the process of using TVS tubes, take into account the discreteness of TVS, and minimize the number of serial combinations;

In the circuit safety protection scheme, the specific type of TVS tube to choose to protect the circuit also needs to be completed under the guidance of professional electronic engineers. Generally, professional TVS tube manufacturers can provide free selection services, scheme design, and sample applications.

If you go to TDK and other manufacturers that make TVS diodes, you should have relevant information on the official website.

Transient Suppression Diode (TVS) is a kind of high-efficiency circuit protection device commonly used in the world, its appearance is the same as that of ordinary diodes, but it can absorb up to several kilowatts of surge power, its main feature is that under reverse application conditions, when subjected to a high energy pulse, its working impedance immediately drops to a very low on-on value, so as to allow large currents to pass through, while clamping the voltage at a predetermined level, its response time is only 10-12 seconds, Therefore, it can effectively protect the delicate components in the electronic circuit.

Condition suppression diodes are used to protect input and output interfaces, VCC buses, and vulnerable circuits in telecommunications equipment, computers, industrial equipment, and consumer electronics from high-voltage transient currents generated by lightning strikes, inductive load switches, and electrostatic discharge (ESD). TVS diode packages are available in two types: surface-mount and axial-leaded.

When the two poles of the diode are subjected to the reverse transient high-energy impact, it can change the high impedance between the two poles into low impedance at a speed of 10 to the minus 12 seconds, absorb up to several kilowatts of surge power, make the voltage clamp between the two poles at a predetermined value, and effectively protect the precision components in the electronic circuit from the damage of various surge pulses. Shenzhen Guangsheng Electronics will answer for you, I hope it can help you.

TVS diodes are referred to as TVS transistors, and the electrical characteristics of TVS transistors are determined by the P-N junction area, doping concentration and wafer resistance. Its ability to withstand surge currents is proportional to its p-n junction area.

When the circuit has abnormal overvoltage and reaches its breakdown voltage, it quickly changes from high impedance to low impedance state, providing a low impedance conduction path for the instantaneous current, and at the same time clamping the abnormal high voltage within a safe level, so as to protect the protected IC or line; When the abnormal overvoltage disappears, it returns to a high-impedance state and the circuit works normally.

TVS tubes are widely used in the protection of semiconductors and sensitive devices, and are usually used for the protection of diode power supplies and signal circuits, as well as anti-static. It is characterized by fast response speed, small size, large pulse power, low clamping voltage, etc. Its 10 1000us wave pulse power from 200W to 30kW, pulse peak current from; The breakdown voltage has a series of values from the range, which is convenient for a variety of circuits with different voltages.