AN320 Datasheet, PDF (1/13 Pages) Extech Instruments Corporation. – AN300 Series Large Vane CFM/CMM Thermo-Anemometers

AN320
Application note
Operation of a Trisil™ crowbar type protection diode
Introduction
In the field of parallel protection, the devices used have two main functions in transient
operation.
■ Limit the voltage.
■ Divert the surge current.
If the first function is carried out perfectly by an avalanche junction, confirmed by the
success of the Transil™ series, the second is limited by voltage permanently present across
the diode terminals.
Use of increasingly sophisticated but fragile electronic components and publication of new
standards do not allow the use of Transil diodes in certain applications. This problem is
solved by the use of a semiconductor device with two conducting states such as the thyristor
(or Triac in the bidirectional version).
STMicroelectronics has developed this type of component under the trade name of Trisil.
This Application note describes the operation of the Trisil.
Figure 1. I / V characteristic of a Trisil
I
I_PP
Transient
operation
Standby
I_H
operation
I_BO
I_RM
V
A
0
V_RM V_BR V_BO
B
C
D
TM: Trisil is a trademark of STMicroelectronics
TM: Transil is a trademark of STMicroelectronics
July 2010
Doc ID 5649 Rev 3
1/13
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