MJW16212 ON Semiconductor, MJW16212 Datasheet - Page 8

• Manufacturer Part Number: MJW16212
• Description: Npn Transistor Bipolar Power Deflection Transistor For High And Very High Resolution Monitors
• Manufacturer: ON Semiconductor

EMITTER–BASE TURN–OFF ENERGY, EB
included on the SCANSWITCH data sheets. Typical
techniques for driving horizontal outputs rely on a pulse
transformer to supply forward base current, and a turnoff
network that includes a series base inductor to limit the rate
of transition from forward to reverse. An alternate drive
scheme has been used to characterize the SCANSWITCH
series of devices (see Figure 2). This circuit ramps the base
drive to eliminate the heavy overdrive at the beginning of the
collector current ramp and underdrive just prior to turn–off
observed in typical drive topologies. This high performance
drive has two additional important advantages. First, the
Emitter–base turn–off energy is a new specification
V
R
R
R
I
I
I
B1
B2
CC
C
B1
B2
V
to give specified
off drive
L
(off)
adjusted
t
Per Spec
Per Spec
s
250 V
3.3
5.5 A
1.1 A
28
and t
f
Table 3. Resistive Load Switching
(off)
Figure 13. Thermal Response
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MJW16212
8
configuration of T1 allows L
of forward base current making it unnecessary to expend
energy to reverse the current flow as in a series based
inductor. Second, there is no base resistor to limit forward
base current and hence no power loss associated with setting
the value of the forward base current. The ramp generating
process stores rather than dissipates energy. Tailoring the
amount of energy stored in T1 to the amount of energy,
EB
results in essentially lossless operation. [Note: B+ and the
primary inductance of T1 (L
= EB
(off)
(off)
, that is required to turn the output transistor off
.]
P
b
) are chosen such that 1/2L
to be placed outside the path
P
l
b
2