page

date

DESCRIPTION: dc-dc converter

3 of 3

11/2008

20050

phone

phone 503.612.2300 fax

fax 503.612.2382

PART NUMBER: VASD1-DIP Series

APPLICATION NOTES:

- Requirement on output load

To ensure this module can operate efficiently and reliably,

the minimum output load should not be less than 10% of the

full load. Also, this product should never be operated under

no load conditions. If the actual output power is too small,

please connect a resistor with proper resistance at the output

end in parallel to increase the load.

- Overload protection

Under normal operating conditions, the output circuit of these

products has no protection against overload. The simplest

method is to connect a self-recovery fuse in series at the

input end or to add a circuit breaker to the circuit.

- Recommended circuit

If you want to further decrease the input/output ripple, an “LC”

filtering network may be connected to the input and output

ends of the dc-dc converter, see (Figure 1).

It should also be noted that the inductance and the frequency

of the “LC” filtering network should be staggered with the

dc-dc frequency to avoid mutual interference. However, the

capacitance of the output filter capacitor must be proper. If the

capacitance is too big, a startup problem might arise. For

every channel of output, provided that safe and reliable

operation is ensured, the recommended capacitance of its

filter capacitor see (Table 1).

It is not recommended to connect any external capacitor in the

application field with less than a 0.5 watt output.

Vin

(VDC)

Cin

(uF)

Vout

(VDC)

Cou

(uF)

5

4.7

4.7

12

2.2

2.2

15

2.2

1

24

1

0.47

TABLE 1

- Output voltage regulation and over-voltage protection circuit

The simplest device for output voltage regulation, over-voltage

and over-current protection is a linear voltage regulator with

overheat protection that is connected to the input or output

end in series (Figure 2).

No parallel connection or plug and play.

FIGURE 1

FIGURE 2