S2006FS221V Teccor Electronics, Inc., S2006FS221V Datasheet - Page 185

• Manufacturer Part Number: S2006FS221V
• Description: Thyristor Product Catalog
• Manufacturer: Teccor Electronics, Inc.

9
Introduction
This application note presents design tips and facts on the follow-
ing topics:
•
•
•
•
•
•
•
Relationship of I
Since a single rectifier or SCR passes current in one direction
only, it conducts for only half of each cycle of an AC sinewave.
The average current (I
mined for full-cycle conduction, and the RMS current (I
equal to the square root of half the mean-square value for full-
cycle conduction or half the peak current (I
cycle sinewave conduction (as in a single-phase half-wave cir-
cuit), the relationships of the rectifier currents can be shown as
follows:
When two identically rated SCRs are connected inverse parallel
for full-wave operation, as shown in Figure AN1009.1, they can
handle 1.41 times the RMS current rating of either single SCR.
Therefore, the RMS value of two half sinewave current pulses in
one cycle is 2 times the RMS value of one such pulse per cycle.
Figure AN1009.1
©2002 Teccor Electronics
Thyristor Product Catalog
Relationship of I
dv/dt Definitions
Examples of gate terminations
Curves for Average Current at Various Conduction Angles
Double-exponential Impulse Waveform
Failure Modes of Thyristor
Characteristics Formulas for Phase Control Circuits
I
I
I
I
I
I
PK
AV
PK
RMS
AV
RMS
= (1 ) I
= (2 ) I
=
= 2 I
= 0.5 I
=
I
RMS
AV
/2) I
= 3.14 I
PK
PK
RMS
AV
= 0.32 I
= 1.57 I
= 0.64 I
SCR Anti-parallel Circuit
AV
, I
AV
AV
AV
RMS
, I
PK
) then becomes half of the value deter-
AV
RMS
, and I
RMS
, and I
PK
PK
PK
). In terms of half-
Miscellaneous Design Tips and Facts
RMS
) is
AN1009 - 1
dv/dt Definitions
The rate-of-rise of voltage (dv/dt) of an exponential waveform is
63% of peak voltage (excluding any overshoots) divided by the
time at 63% minus 10% peak voltage. (Figure AN1009.2)
Figure AN1009.2
The rate-of-rise of voltage (dv/dt) of a linear waveform is 80% of
peak voltage (excluding any overshoots) divided by the time at
90% minus 10% peak voltage. (Figure AN1009.3)
Figure AN1009.3
Exponential dv/dt =
Resistor Capacitor circuit t = RC =
Resistor Capacitor circuit
Linear dv/dt =
Linear dv/dt =
100%
63%
10%
90%
10%
0%
0%
t 0
t 0
(Peak Value)
t 1
t 1
Exponential dv/dt Waveform
Linear dv/dt Waveform
0.8
0.9 V
0.63
V
t 2
PK
PK
t 2
–
4 RC
Numerical dv/dt
=
0.1 V
V
AN1009
PK
t
2
–
t 1
=
PK
=
t
2
t
t
3
2
–
=
–
–
t 1
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t
t 1
2
t
2
Time
–
[phone]
t 1
Time
t 3