K1500SRP Datasheet, PDF (6/7 Pages) Littelfuse – High-voltage lamp ignitors

Sidac
Data Sheets
(a) Circuit
VDC(IN) ≥ VB0
R
SIDAC
VC
VBO
VC
(b) Waveforms
t
C
IL
RL
IL
Rmax ≤
VIN - VBO
IBO
t
Rmin _≥
VIN - VTM
IH _(MIN)
Figure E9.15 Relaxation Oscillator Using a Sidac
Input
(See Note B)
2N6127
(or equivalent)
R_{BB1 =}
150 Ω
50 Ω
50 Ω
R_{BB2 =}
100 Ω
V_BB1 =10 V
+ ^VBB2 ⁼⁰
-
Test Circuit
V_CE Monitor
TIP-47
100 mH
+
V_CC = 20 V
-
R_S = 0.1 Ω
I_C Monitor
Input
Voltage
0V
5V
Collector
Current
0.63 A
0
Sidac V_BO
t_w ≈ 3 ms
(See Note A)
t_w
100 ms
Collector
Voltage
10 V
V_CE(sat)
Voltage and Current Waveforms
Note A: Input pulse width is increased until I_CM = 0.63 A.
Note B: Sidac (or Diac or series of Diacs) chosen so that V_BO is just below V_CEO rating of transistor to be protected.
The Sidac (or Diac) eliminates a reverse breakdown of the transistor in inductive switching circuits where otherwise the
transistor could be destroyed.
Figure E9.16 Sidac Added to Protect Transistor for Typical Transistor Inductive Load Switching Requirements
Ballast
H.V.
Step-up
Transformer
0.1 – 0.15 µF
220 V / 240 V
50 / 60 Hz
0.22 – 0.33µF
K2401F1
5 – 6µH
Metal
Halide
Lamp
5.6K – 8.2K
5W
Figure E9.17 Typical Metal Halide Ignitor Circuit
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E9 - 6
©2004 Littelfuse, Inc.
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