ACT30
Active- Semi
Rev 5, 05-Jun-09
Figure 4:
APPLICATIONS INFORMATION
NPN Reverse Bias Safe Operation Area
External Power Transistor
IC
The ACT30 allows a low-cost high voltage power
NPN transistor such as ‘13003 or ‘13002 to be used
safely in a flyback configuration. The required
collector voltage rating for VAC = 265V with full
output load is at least 600V to 700V. As seen in
Figure 4, the breakdown voltage of an NPN is
significantly improved when it is driven at its emitter.
Thus, the ACT30 and ’13002 or ‘13003 combination
meet the necessary breakdown safety requirement
even though RCC circuits using ‘13002 or ‘13003
do not. Table 1 lists the breakdown voltage of some
transistors appropriate for use with the ACT30.
Base-Drive
Safe Region
(RCC)
Emitter-Drive
Safe Region
(ACT30)
VCEO
VCBO
VC
The power dissipated in the NPN transistor is equal
to the collector current times the collector-emitter
voltage. As a result, the transistor must always be
in saturation when turned on to prevent excessive
power dissipation. Select an NPN transistor with
sufficiently high current gain (hFEMIN > 8) and a base
drive resistor (R2 in Figure 1) low enough to ensure
that the transistor easily saturates.
Table 1:
Recommended Power Transistor List
DEVICE VCBO VCEO IC hFEMIN PACKAGE
MJE13002 600V 300V 1.5A
8
8
8
TO-126
TO-126
TO-92
MJE13003,
700V 400V 1.5A
KSE13003
STX13003 700V 400V 1A
Figure 5:
A 3.75W Charger Using ACT30A in Combination with TL431
F1
AC1
C10
D8
R18
D1
D4
D3
T1
EE-16
L1
L2
5V/750mA
R1
C19
D5
R9 R10
D2
C1
C4
R11
C9
R3
C7
R2B
R2A
AC2
IC2A
Opto
C2
R6
R13
D6
R5
C8
D7
R7
IC3
TL431
Q2
R12
R16
Z1
R15
R14
GND
IC2B Opto
1
3
IC1
ACT30A
C6
R8
C5
C20
C3
Innovative PowerTM
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ACTIVE-SEMI [ ACTIVE-SEMI, INC ]
