AN1376 datasheet(13/35 Pages) STMICROELECTRONICS

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AN1376 APPLICATION NOTE

affect the response. To avoid any expensive solution to improve it the better way is to measure

the voltage regulation during the normal operation, powering the real load circuitry. This, be-

cause there are some local capacitors or filters helping a lot the regulation. Moreover, normally

the dynamic load changes are less than the testing value indicated.

The regulation for all the other output voltage is good, remaining well within tolerances.

■

Unregulated Outputs

The following tests show the response of the output voltages varying the load for each unreg-

ulated output. The load conditions are specified at the right of each picture. The regulation

has been tested at both the nominal mains voltages.

Figure 10.

@115 VAC - 50Hz

CH1:

+12 Vout

CH2:

+7 Vout

CH3:

+3V3 Vout

CH4:

+5V Iout

+3,3V +5V, +7V, +30V: FULL LOAD

+12V: DYNAMIC LOAD 0.1 to 0.7A, 70Hz

@ 220Vac the waveforms have the same

amplitude.

CH1:

+12 Vout

CH2:

+7 Vout

CH3:

+3V3 Vout

CH4:

+12V Iout

+3,3V +5V, +7V, +30V: FULL LOAD

+5V: DYNAMIC LOAD 0.5 to 1.1A, 70Hz

5V modulation: 20 mVpp

@ 220Vac the waveforms have the same

amplitude.

ALL THE VOLTAGES ARE WITHIN TOLERANCES, AT BOTH INPUT MAINS VOLTAGES

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