How to identify and judge high-efficiency diodes?

How to identify and judge high-efficiency diodes?

In the field of power management and power conversion, high-efficiency diodes are mainly characterized by low forward voltage drop and fast switching speed, thereby improving the overall efficiency of the circuit.

1. The basic characteristics of high-efficiency diodes

High-efficiency diodes are characterized by lower forward voltage drop and shorter recovery times compared to conventional diodes. The low forward voltage drop means that the diode will have less power loss in the on-state, which is especially important for power conversion circuits. In addition, the fast recovery time helps to reduce switching losses and is suitable for high-frequency applications.

Common types of high-efficiency diodes include Schottky diodes and Ultra-Fast Recovery diodes. Schottky diodes typically have a forward voltage drop between 0.2V and 0.4V, while ultrafast recovery diodes are known for their nanosecond recovery times.

2. Identification method of high-efficiency diode

Appearance Recognition:

High-efficiency diodes are typically available in small packages to accommodate high-frequency and high-efficiency applications. For example, common package types for Schottky diodes include SMA, SMB, SOD-123, etc. The package is usually printed with the model number and polarity designation, which usually indicates the cathode direction of the diode with a ring mark.

Model Identification:

The model number of the diode is usually directly assigned to the device, such as the common 1N5819 (Schottky diode) or UF4007 (ultrafast recovery diode). With these models, detailed diode parameters such as forward voltage drop, maximum forward current, and reverse recovery time can be queried. This information can help engineers quickly identify whether a high-efficiency diode is a diode and determine if it is suitable for a particular application.

Polarity Identification:

The polarity of a diode can be easily determined using a multimeter. Place the multimeter in the diode position or resistance position and test both ends of the diode separately. If the reading is low, the red pen is in contact with the anode, and the black pen is in contact with the cathode; Otherwise, it is reversed. High-efficiency diodes generally have a lower forward voltage drop than silicon diodes, so their measurements should be different from those of normal diodes.

3. Performance judgment of high-efficiency diodes

Forward Pressure Drop Test:

Low forward voltage drop is a characteristic feature of high-efficiency diodes, especially Schottky diodes. The forward voltage drop of the diode can be measured directly using the diode position of the multimeter. For Schottky diodes, the forward voltage drop should be between 0.2V and 0.4V, and for ultrafast recovery diodes, the forward voltage drop is typically around 0.7V, but the recovery time is much shorter than that of ordinary diodes.

Reverse Recovery Time Test:

Reverse recovery time is one of the important parameters of high-efficiency diodes. An oscilloscope can be used to test the reverse recovery time of a diode, which is especially important for circuits such as high-frequency switching power supplies and inverters. The shorter the reverse recovery time, the better the diode will perform in high-frequency applications. Schottky diodes typically do not involve a reverse recovery time test because their operating principle dictates that there is no stored charge; But for ultra-fast recovery diodes, this test is crucial.

Reverse Current Test:

High-efficiency diodes typically have a small leakage current when they are back-biased. The reverse current of the diode can be measured using a multimeter or special test equipment. Excessive reverse leakage current may mean that the diode is of poor quality