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WESTCODE An IXYS Company
Medium Voltage Thyristor Types K0566L#440 to K0566L#520
9.3 Calculating VT using ABCD Coefficients
The on-state characteristic IT vs. VT, on page 6 is represented in two ways;
(i) the well established VT0 and rT tangent used for rating purposes and
(ii) a set of constants A, B, C, D, forming the coefficients of the representative equation for VT in
terms of IT given below:
VT = A + B ⋅ ln(IT ) + C ⋅ IT + D ⋅ IT
The constants, derived by curve fitting software, are given below for the hot and cold characteristics. The
resulting values for VT agree with the true device characteristic over a current range, which is limited to
that plotted.
25°C Coefficients
A -3.601622e-3
B 0.3236869
C 1.366986e-3
D -0.03236849
125°C Coefficients
A -1.819017
B 0.79521
C 2.47e-3
D -0.094268
10.0 Snubber Components
When selecting snubber components, care must be taken not to use excessively large values of snubber
capacitor or excessively small values of snubber resistor. Such excessive component values may lead to
device damage due to the large resultant values of snubber discharge current. If required, please consult
the factory for assistance.
11.0 Reverse recovery ratings
(i) Qra is based on 50% Irm chord as shown in Fig. 1
(ii) Qrr is based on a 150µs integration time i.e.
150 µs
∫Qrr = irr .dt
0
(iii)
K
Factor
=
t1
t2
Fig. 1
12.0 Duty cycle lines
The 100% duty cycle is represented on the frequency ratings by a straight line. Other duties can be
included as parallel to the first.
Provisional Data Sheet. Types K0566L#440 to K0566L#520 Issue 1
Page 5 of 11
July, 2008

 5 Page



WESTCODE An IXYS Company
Figure 17 – Square Wave Frequency Ratings
1.00E+05
200A
500A
K0566L#440-520
AD Issue 1
di/dt=50A/µs
TK=55°C
1.00E+04
750A
100% Duty Cycle
1000A
1.00E+03 2000A
1.00E+02
Medium Voltage Thyristor Types K0566L#440 to K0566L#520
Figure 18 – Sine Wave Frequency Ratings
1.00E+05
K0566L#440-520
AD Issue 1
TK=55°C
100% Duty Cycle
500A
1.00E+04
750A
1000A
1.00E+03 2000A
1.00E+01
1.00E-05
1.00E-04
1.00E-03
Pulse width (s)
1.00E-02
1.00E+02
1.00E-05
Figure 19 – Maximum surge and I2t Ratings
100000
Gate may temporarily lose control of conduction angle
K0566L#440-520
AD Issue 1
Tj (initial) = 125°C
1.00E-04
1.00E-03
Pulse Width (s)
1.00E-02
1.00E+07
10000
I2t: VRRM≤10V
I2t: 60% VRRM 1.00E+06
ITSM: 60% VRRM
1000
1
3 5 10
Duration of surge (ms)
ITSM: VRRM≤10V
1
5 10
50 100
1.00E+05
Duration of surge (cycles @ 50Hz)
Provisional Data Sheet. Types K0566L#440 to K0566L#520 Issue 1
Page 10 of 11
July, 2008

 10 Page