DCP02_08 Datasheet, PDF (7/20 Pages) Texas Instruments – Miniature, 2W, Isolated UNREGULATED DC/DC CONVERTERS

DCP02 Series
www.ti.com
SBVS011K – MARCH 2000 – REVISED FEBRUARY 2008
ADDITIONAL FUNCTIONS
DISABLE/ENABLE
The DCP02 can be disabled or enabled by driving the
SYNC pin using an open drain CMOS gate. If the
SYNC pin is pulled low, the DCP02 will be disabled.
The disable time depends upon the external loading;
the internal disable function is implemented in 2µs.
Removal of the pull down causes the DCP02 to be
enabled.
Capacitive loading on the SYNC pin should be
minimized in order to prevent a reduction in the
oscillator frequency.
DECOUPLING
Ripple Reduction
The high switching frequency of 400kHz allows
simple filtering. To reduce ripple, it is recommended
that a 1µF capacitor be used on V_OUT. Dual outputs
should both be decoupled to pin 5. A 2.2µF capacitor
on the input is also recommended.
Connect the positive V_OUT from one DCP02 to the
negative V_OUT (0V) of another (see Figure 7). If the
SYNC pins are tied together, the self-synchronization
feature of the DCP02 prevents beat frequencies on
the voltage rails. The SYNC feature of the DCP02
allows easy series connection without external
filtering, thus minimizing cost.
The outputs on the dual-output DCP02 versions can
also be connected in series to provide two times the
magnitude of V_OUT, as shown in Figure 8. For
example, a dual 15V DCP022415D could be
connected to provide a 30V rail.
Connecting the DCP02 in Parallel
If the output power from one DCP02 is not sufficient,
it is possible to parallel the outputs of multiple
DCP02s, as shown in Figure 9. Again, the SYNC
feature allows easy synchronization to prevent
power-rail beat frequencies at no additional filtering
cost.
Connecting the DCP02 in Series
Multiple DCP02 isolated 2W DC/DC converters can
be connected in series to provide nonstandard
voltage rails. This configuration is possible by using
the floating outputs provided by the galvanic isolation
of the DCP02.
V_SUPPLY
V_S
C_IN(1)
0V
+V_OUT
DCP
02
-V_OUT
0V
C_OUT
1.0mF
+V_OUT
C_OUT ^-VOUT
1.0mF
COM
NOTE: (1) C_IN requires a low-ESR ceramic capacitor: 5V to 15V version is 2.2mF;
24V version is minimum 0.47mF.
Figure 8. Connecting Dual Outputs in Series
V_SUPPLY
COM
C_IN(1)
C_IN(1)
V_S
SYNC _{DCP 02}
0V
V_S
SYNC _{DCP 02}
0V
V_OUT
0V
V_OUT
0V
C_OUT
1.0mF
2 x Power Out
C_OUT
1.0mF
NOTE: (1) C_IN requires a low-ESR ceramic capacitor: 5V to 15V version is 2.2mF;
24V version is minimum 0.47mF.
Figure 9. Connecting Multiple DCP02s in Parallel
Copyright © 2000–2008, Texas Instruments Incorporated
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