Vivanco UNIVERSAL SWITCHMODE AC TO DC MAINS ADAPTERS WITH USB CHARGING FUNCTION Guide de l'utilisateur télécharger pdf (Page 103)

Test Results

B.3 OUTPUT VOLTAGE RIPPLE

Output voltage ripple is measured across the output capacitors with the shortest probe

ground possible. For production tests, the output voltage ripple is measured at the

terminal blocks. Refer to Figure B-9 for the oscilloscope probe connection location

used to measure the output voltage ripple.

FIGURE B-9: EXAMPLE OF OSCILLOSCOPE PROBE CONNECTION

B.3.1 Test Procedure

1. Ensure that the system is OFF and all probes are disconnected.

2. Connect the oscilloscope probe across the output capacitor to be measured as

shown in Figure B-9.

3. Set up the oscilloscope with a time scale of 2 µs and set the oscilloscope channel

to AC coupling and 50 mV per division.

4. Measure the peak-to-peak voltage.

5. To test the output voltage ripple with a load, connect a programmable DC load to

the output terminal and re-measure the voltage ripple.

6. Turn off the system and disconnect all probes.

Figure B-10 through Figure B-12 show the output voltage ripple of each stage without

load.

Probe connection point

Note: Oscilloscope probes should have the shortest ground wire possible to

eliminate noise when measuring the ripple voltage.

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Vivanco UNIVERSAL SWITCHMODE AC TO DC MAINS ADAPTERS WITH USB CHARGING FUNCTION Guide de l'utilisateur Page 103