Common test methods for voltage drop of Schottky diode — SUNMATE
Schottky diode has the advantages of low impedance, small forward voltage drop and fast recovery, so it is often used in high-frequency high-current rectification and power-down protection lines. Schottky diode has fast recovery speed and can be used in h
Common test methods for voltage drop of Schottky diode
Test with the "DCPOWERSUPPLY" instrument (constant current stabilized DC current): first give a small voltage so that there is current flowing through the Schottky diode, then slowly increase the current to reach the rated current of the measured Schottky diode, and then read after the voltage value is stable. The stable reading is the voltage drop of the rated current.
Why is the stable voltage reading the correct voltage drop reading: the impedance of Schottky diode is not fixed, but decreases with the temperature rise (non-linear relationship).
When there is current passing through the Schottky diode, the tube core will generate heat and then emit it through the tube body. When the heat balance is reached (the heat generated by the tube core can be emitted in time), the impedance at this time is also relatively stable, which is the law of energy conservation (P=I2R, P converted into heat). If the rated current is directly used for testing, the initial reading is on the high side, because the tube core is at normal temperature at this time, and the impedance is the largest, and the reading will gradually decrease with time, which is the reason why the impedance decreases with the increase of temperature.
Common Mistakes in Measuring Voltage Drop of Schottky Diode
Some users directly use a multimeter for testing due to the limitation of the testing instrument. Although the multimeter has the range of testing diodes, its output current is only one or two milliamperes. The measured reading is not "internal resistance", but the voltage drop when the current is milliampere level. Moreover, the reading displayed when testing the voltage drop of each batch of Schottky diodes with this method may have a large deviation. Schottky diodes usually work in amperes, The difference between the two is a thousand times.