For multi-output converters, the main output is typically a fully regulated output.

If the end

application requires critical regulation on the auxiliary output(s), a linear regulator or other

regular should be added after the converter.

(Note: Some MORNSUN converters have built in

linear regulators; please contact our Technical Department for details).

3. AC-DC Converter Safety Related Design Notes

3.1 Marking Requirements

Wherever, there are fuses, protective grounds, or

switches, clear symbols should be indicated

according safety standards. Touchable dangerous high voltage and energy sources should be

marked with

“Caution!” indications.

3.2 Input Cable Requirements:

Input cables of L, N and E should be brown, blue and yellow/green cables, respectively.

Ensure that the ground cable (yellow & green cable) of Type I devices (those that rely on

basic insulation and protection ground to avoid electric shock) are securely connected to the

3.3 Clearance and Creepage

For Type I devices, ensure:

♦ L and N are in front of the fuse.

♦ The clearance distance between the input and the metal case is above 2mm and

creepage is above 2.5mm.

For Type II devices (those that rely on strengthened insulation or double insulation to avoid

electric shock) ensure:

♦ L and N are in front of the fuse

♦ The clearance distance between the input and the metal case is above 2mm and

creepage is above 2.5mm.

♦ The clearance between the input and the metal case or SELV is above 4mm, and

creepage of that is above 5mm.

3.4 Input energy

If the input capacitor is large, a discharge resistor may be added to ensure that, after

disconnect, the voltage held between Input L, N, and the protective ground will be discharged to

37% of its maximum value or below.

In Figure 2, R1 is the discharge resistor.

4. Heat Dissipation in AC/DC Converter Module Applications

Trends toward higher density in AC/DC module designs make heat dissipation an important

concern.

The effect of heat on the electrolytic capacitor is of particular concern, as the life of

such capacitors can be drastically reduced when operated in a constant high temperature

environment, leading to a higher potential for failure. Proper handling of heat will increase the

life of the converter and surrounding components, thus lowering risk of failures. Some