Characteristics of BAV70 diodes and 3 knowledge points of diodes

BAV70 diodes are characterized by small size, fast switching speed and high reliability. They are used in unidirectional isolation of circuits with high signal frequency, computer boards, communications, TV circuits and industrial control circuits. Shenzhen Freixin Electronics has been focusing on two for 16 years. The first-line brand agent of triode, the constant temperature and humidity warehouse is 1000 square meters, the inventory is sufficient, free samples are provided, and one-to-one technical guidance is provided. Today, the editor of Freixin will briefly introduce the five knowledge points of diodes.

1. What is the transient process when the BAV70 diode is conducting? For the transient process of the BAV70 diode, the reverse recovery characteristics are generally more concerned. But in fact, there are also noteworthy points in the process of diode from reverse bias to forward conduction.

When the diode is just conducting, the positive voltage drop first rises high and then falls to the steady state value. This increases as di/dt increases. That is, the forward peak voltage is generated instantaneously when the band of the BAV70 diode is turned on, and the voltage is greater than the steady-state voltage.

2. BAV70 diode parasitic inductance and selection of diode slow and fast diode in RCD clamping circuit The parasitic inductance of BAV70 diode is mainly caused by the lead wire, and can be regarded as the inductance connected in series with the BAV70 diode. RCD circuits are often used where clamping is required. Some literatures believe that a slow recovery tube should be used, because the slow recovery tube has a long reverse recovery time. Therefore, in order to reduce the loss of the clamping circuit, the clamping capacitor will feed back part of the energy to the circuit during the diode reverse recovery process. .

This product is only suitable for low current, low di/dt occasions. However, it is not suitable to use a high current output power supply secondary clamp circuit such as high di/dt in the clamp circuit. Since the slow recovery transistor will generate a high turn-on voltage drop spike during the turn-on process, the voltage on the clamping capacitor is very low, but it cannot clamp the spike voltage.

3. Is the diode suitable for parallel connection? Silicon BAV70 diodes are not suitable for parallel connection when the conduction voltage drop decreases when the temperature rises, but many diodes now package two single tubes together, and the temperature rise is relatively uniform, which is conducive to parallel connection. But silicon carbide is different. Its pressure drop increases with temperature and is theoretically suitable for parallel connection.