The Relationship between Forward Conduction Voltage Drop and Conduction Current of Fast Recovery Diodes

The Relationship between Forward Conduction Voltage Drop and Conduction Current of Fast Recovery Diodes

What is the relationship between the forward conduction voltage drop of the Fast Recovery Diodes and the conduction current?

When the forward bias voltage is applied at both ends of the fast recovery diode, the internal electric field area becomes narrow, and a large forward Diffusion current can pass through the PN junction. Only when the forward voltage reaches a certain value (referred to as the "threshold voltage", which is about 0.2V for germanium tubes and 0.6V for silicon tubes), can the fast recovery diode truly conduct.

Is the conduction voltage drop of the fast recovery diode constant? What relationship does it have with the forward Diffusion current? By testing the relationship between the conduction current and the conduction voltage drop of the Fast Recovery Diodes model at room temperature using the test circuit shown in Figure 1, the curve relationship shown in Figure 2 can be obtained: the forward conduction voltage drop is proportional to the conduction current, and the floating voltage difference is 0.2V. Although the voltage difference from light load conduction current to rated conduction current is only 0.2V, for power Fast Recovery Diodes, it not only affects efficiency but also affects the temperature rise of the fast recovery diode. Therefore, if price conditions allow, try to choose a fast recovery diode with a small conduction voltage drop and a rated working current that is twice the actual current.