AN4840 Datasheet, PDF (1/6 Pages) Dynex Semiconductor – Gate Triggering and Gate

Introduction:
In all thyristor data sheets a set of curves
showing device gate characteristics is given.
This gives information fundamental to the
correct triggering of the thyristor but the right
interpretation sometimes causes problems.
Note, the curves should be used in
conjunction with the table of ratings and
trigger characteristics given elsewhere in each
data sheet. This table gives the relevant test
conditions.
In this application note two types of gate
curve are shown (Fig. 1a to c). Fig 1(a) shows
the traditional format with logarithmic 'X' and
'Y' axes. This version allows a wide range of
gate current and voltage to be shown. Fig
AN 4840
Gate Triggering and Gate
Characteristics
Application Note
AN4840-4 July 2014 LN31796
Authors: Colin Smith; Colin Rout
1(b) and 1(c) show curves with linear axes (2
graphs are needed to be the equivalent of Fig
1(a)). When gate drive load lines are to be
superimposed linear versions are much more
user friendly - see below.
Information provided by curves
Igt, Vgt. The value of gate current, Ig and
voltage, Vg to be supplied to the thyristor to
guarantee simple triggering should always be
greater than the appropriate data book values
of Igt and Vgt. Simple triggering is adequate
for low di/dt applications only - see below.
Note, that although the device may trigger at
Ig and Vg values below the Igt and Vgt values
shown, no guarantee can be given.
Fig 1a
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