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Characteristics, functions, and applications – TDK J Series JBW User Manual

Page 18

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004-02 / 20070523 / ea122_jbw.fm

• All specifications are subject to change without notice.

Characteristics, Functions, and Applications

RIPPLE NOISE MEASUREMENT CONDITIONS

SERIES OPERATION (TO INCREASE OUTPUT VOLTAGE OR

TO OBTAIN SEPARATE ±OUTPUT)

When the output voltage of a single power supply is insufficient,

several power supplies can be connected in series in order to

obtain a higher voltage or separate ±outputs.

If power supplies A and B in the illustration below are 5V each, a

10V output can be obtained in this connection. It should be noted

that, however, the output current is limited to the lower rated cur-

rent value of the power supplies A and B. There is no problem if

the voltages of A and B are different from each other.

D1 and D2 in the illustration designate diodes for preventing

reverse voltage application. They are provided for preventing inter-

nal components of the power supply having the lower rated voltage

from being damaged by an applied reverse voltage caused by a

short circuit in the load or the like.

Use diodes which meet the following requirements:

Reverse withstanding voltage: Over twice that of the combined

output voltage

Forward current: Over twice that of the output current

Forward voltage drop: As small as possible

(e.g. Shottkey diode, etc.)

SERIES CONNECTION FOR INCREASING OUTPUT VOLTAGE

INSULATION AND WITHSTAND VOLTAGE TESTS

The insulation and withstand voltage tests may cause deteriora-

tion. Care must be taken for execution of the tests. The potential

must be equal among input, output, and FG (frame ground) termi-

nals. It is preferable to use testers that gently start up at the test-

ON and automatically discharge charged energy at the test-OFF.

Manual discharging after the tests should be through a resistor

around 100k

Ω to 1MΩ (Do not perform discharging at low imped-

ance. It may cause deterioration.)

In any case, take full countermeasures for electric-shock preven-

tion.

OTHER CONDITIONS

• Unless conditions are otherwise specified in the specifications or

standards, 25°C and rated input-output should be applied.

L

+

C

1

C

2

Output connector

Load

Output ripple and noise measurement point (20MHz)

C

1

C

2

L

: 100µF Electrolytic capacitor
: 0.1µF Film capacitor
: 150mm

D1

D2

Power supply A

Power supply B

Load

∗ For obtaining separate ±outputs, (A) should be zero voltage.

(A)∗

+

+