Fast Recovery Diode Function Analysis
Author: Shenzhen Yuan Zhi Electronics Co., Ltd.Time:2018-03-01 17:15:27Views:2526【SML】
A PN junction rectifier diode that quickly transitions from an
on state to an off state is called a fast recovery diode. This diode is
characterized by a short reverse recovery time, typically 200v ...
label:
A PN junction rectifier diode that quickly transitions from an
on state to an off state is called a fast recovery diode. This diode is
characterized by a short reverse recovery time, typically 200v / 30A
fast recovery diode with trr <1μs.
The
main feature of the fast recovery diode is the very short time it takes
to turn this diode on and off, which is called the reverse recovery
time. A smaller tube with a reverse recovery time significantly reduces
the power dissipation during switching. In addition, it is often used to generate a rapidly rising pulse signal. Fast
recovery diode, the role of fast recovery diode As the high-level
transition to low diode, or from low to high transition period, the
conversion time is longer, will seriously affect the speed of the
circuit, Ultimately lead to the characteristics of the circuit is not good!
Fast
recovery diode is between the Schottky and ordinary 2-diode, it both
the Schottky diode on-voltage drop (there is no low Schottky), fast,
there are high voltage Te
base is generally low pressure), fast recovery is mainly used for the
rectification of the higher frequency occasions, such as the secondary
rectification of switching power supply for the rectification of mains,
fast recovery diode is no problem, but due to fast recovery diode
material and Process
reasons, it's fast recovery diode, the role of fast recovery diode
Analysis PN junction rectifier to be thinner in the past, the ability of
large current over the weak, especially in the filter capacitor is too
large, the tube Improper selection of the maximum current will burn the fast recovery PN junction in a flash.
Routine detection of fast recovery diodes
The
use of multimeter to detect fast recovery, ultra-fast recovery diode
unidirectional conductivity, and the internal open-circuit,
short-circuit failure, and can detect the forward voltage drop. If accompanied by megger, fast recovery diode can also measure the reverse breakdown voltage. The company is located in:
Example: Measuring an ultrafast recovery diode, the main parameters are: trr = 35ns, IF = 5A, IFSM = 50A, VRM = 700V. Will
quickly restore the diode, the role of fast recovery diode Multimeter
dial to R × 1 file, read out the forward resistance of 6.4Ω, n '= 19.5
cells; reverse resistance is infinite. VF = 0.03V / cell × 19.5 = 0.585V was further obtained. Prove the pipe is good.
Precautions:
1) Some single tube, a total of three pins, the middle of the empty
feet, generally cut off at the factory, but there are also not cut.
2) If there is a tube in the tube is damaged, can be used as a single tube.
3) When measuring forward voltage drop, R × 1 gear must be used. If
R × 1k file, because the test current is too small, much lower than the
normal tube current, so the measured VF value will be significantly
lower. In the above example, if you choose R × 1k file measurement, the forward resistance is equal to 2.2kΩ, n '= 9 cells. VF calculated from this only 0.27V, much lower than the normal value (0.6V).
2018-03-01
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