MJW16212 Datasheet, PDF (5/8 Pages) Motorola, Inc – POWER TRANSISTOR 10 AMPERES 1500 VOLTS - VCES 50 AND 150 WATTS

MJW16212
DYNAMIC DESATURATIION
The SCANSWITCH series of bipolar power transistors are
specifically designed to meet the unique requirements of hor-
izontal deflection circuits in computer monitor applications.
Historically, deflection transistor design was focused on mini-
mizing collector current fall time. While fall time is a valid
figure of merit, a more important indicator of circuit perfor-
mance as scan rates are increased is a new characteristic,
“dynamic desaturation.” In order to assure a linear collector
current ramp, the output transistor must remain in hard satu-
ration during storage time and exhibit a rapid turn–off transi-
tion. A sluggish transition results in serious consequences.
As the saturation voltage of the output transistor increases,
the voltage across the yoke drops. Roll off in the collector
current ramp results in improper beam deflection and distor-
tion of the image at the right edge of the screen. Design
changes have been made in the structure of the SCANS-
WITCH series of devices which minimize the dynamic desa-
turation interval. Dynamic desaturation has been defined in
terms of the time required for the VCE to rise from 1.0 to
5.0 volts (Figures 9 and 10) and typical performance at opti-
mized drive conditions has been specified. Optimization of
device structure results in a linear collector current ramp, ex-
cellent turn–off switching performance, and significantly low-
er overall power dissipation.
+ 24 V
Table 2. High Resolution Deflection Application Simulator
C1 ⁺
100 µF
U2
MC7812
VI
G
N
VO
D
+
C2
10 µF
Q2
MJ11016
(IB)
R1
1k
R5 ^(IC)
Q5
1k
MJ11016
R7
R8
R9
2.7 k
9.1 k
470
6.2 V
+ C3
R10
10 µF
47
C6 ⁺
100 µF
LY
R2
R510
SYNC
R3
250
Q1
C4
C5
0.005
0.1 _R11
76
470
(DC) ^{OSC VCC}
1W
8 _{% OUT} 1
U1
R6
GND _MC1391P
1k
2
BS170
T1: Ferroxcube Pot Core #1811 P3C8
Primary/Sec. Turns Ratio = 18:6
Gapped for LP = 30 µH
Q3
MJE
15031
100 V
T1
R12
470
1W
D1
MUR110
LB = 1.5 µH
CY = 0.01 µF
LY = 13 µH
5
D2
MUR460
LB
R4
22
CY
VCE
Q4
DUT
IB1 = 1.3 A
DYNAMIC DESATURATION TIME
4 _{IS MEASURED FROM VCE = 1 V}
TO VCE = 5 V
3
IB2 = 4.9 A
2
TIME (2 µs/DIV)
Figure 9. Deflection Simulator Circuit Base
Drive Waveform
1
tds
0
0
2
4
6
8
10
TIME (ns)
Figure 10. Definition of Dynamic
Desaturation Measurement
Motorola Bipolar Power Transistor Device Data
3–5