K0900E70 Datasheet, PDF (124/224 Pages) Teccor Electronics – Thyristor Product Catalog

AN1001
Application Notes
Electrical Characteristic Curves of Thyristors
+I
Voltage Drop (V_T) at
Specified Current (i_T)
Latching Current (I_L)
Reverse Leakage
Current - (I_RRM) at
Specified V_RRM
-V
Minimum Holding
Current (I_H)
Specified Minimum
Reverse Blocking
Voltage (V_RRM)
Off - State Leakage
Current - (I_DRM) at
Specified V_DRM
+V
Specified Minimum
Off - State
Blocking
Voltage (V_DRM)
Reverse
Breakdown
Voltage
-I
Forward
Breakover
Voltage
Figure AN1001.12 V-I Characteristics of SCR Device
+I
Voltage Drop (V_T) at
Specified Current (i_T)
Minimum Holding
Current (I_H)
-V
Latching Current (I_L)
Off-state Leakage
Current – (I_DRM) at
Specified V_DRM
+V
Specified Minimum
Off-state
Blocking
Voltage (V_DRM)
Breakover
Voltage
-I
Figure AN1001.13 V-I Characteristics of Triac Device
+I
10 mA
∆V
+I
I_T
I_H
R_S
I_S
-V
I_DRM ^IBO
R_S
=
(V_BO
(I_S -
- V_S)
I_BO)
+V
V_BO
V_T
V_S
V_DRM
-I
Figure AN1001.15 V-I Characteristics of a Sidac Chip
Methods of Switching on Thyristors
Three general methods are available for switching thyristors to
on-state condition:
• Application of gate signal
• Static dv/dt turn-on
• Voltage breakover turn-on
Application Of Gate Signal
Gate signal must exceed I_GT and V_GT requirements of the thyristor
used. For an SCR (unilateral device), this signal must be positive
with respect to the cathode polarity. A triac (bilateral device) can
be turned on with gate signal of either polarity; however, different
polarities have different requirements of I_GT and V_GT which must
be satisfied. Since diacs and sidacs do not have a gate, this
method of turn-on is not applicable. In fact, the single major
application of diacs is to switch on triacs.
Static dv/dt Turn-on
Static dv/dt turn-on comes from a fast-rising voltage applied
across the anode and cathode terminals of an SCR or the main
terminals of a triac. Due to the nature of thyristor construction, a
small junction capacitor is formed across each PN junction.
Figure AN1001.16 shows how typical internal capacitors are
linked in gated thyristors.
Breakover
Current
I_BO
-V
+V
Breakover
Voltage
V_BO
-I
Figure AN1001.14 V-I Characteristics of Bilateral Trigger Diac
Figure AN1001.16 Internal Capacitors Linked in Gated Thyristors
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AN1001 - 4
©2002 Teccor Electronics
Thyristor Product Catalog