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AN1714

Demonstration board characterization

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Demonstration board characterization

This chapter includes a series of tests and measurements to characterize the demonstration

board. The characterization concerns the most critical aspects required by European

standards which are:

Electro-conducted disturbances

Immunity to narrowband conducted noise

Output impedance measurement

The results of these measures show a good match and a very close value to the measures

done according to the EN50065-1, EN50065-2-1 and EN50065-7 setup and procedures.

3.1

Conducted disturbance

The EN50065-1 standard describes the test setup and procedures for these kinds of tests.

The measures have been done with 220 V~ and 110 V~ mains voltages. The test pattern

consists of a continuous transmission of a fixed tone (symbol "0") or a repetition of random

bytes.

The output signal has a peak value of 118dBuV (output CISPR-16 measure of the not

modulated signal) that means a 1.6Vrms of signal on the mains.

The spectrum analyzer performs a peak measure instead of a quasi-peak measure. For

continuous sinusoidal signals the two types of measures give the same result.

Figure 29.

Conducted disturbance setup

As shown by the spectrum plots the point that is usually the closest to the mask is the 2nd

harmonic. The borderline condition is obtained with the 110 V~ mains supply and with the

110 kHz channel.

In the 110 kHz channel case the output board filter centered at the 132.5 kHz channel

produces lower attenuation of the harmonic.

The other critical condition is with the 110 V~ supply. In this case the switching regulator

gives a lower supply voltage. The effect is to compress the top of the output sinusoidal

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