AN2242

3 Cross Regulation and Standby

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3

Cross Regulation and Standby

The following tables show the output voltage measurements and the overall efficiency of the

converter measured at different input voltages. All the output voltages have been measured on

the output connector.

Table 2.

Output Voltage Measurement at Full Load

Table 2. lists the output voltage measurements at both nominal mains range: all voltages are

within the tolerance given in the specification. The efficiency measured is very good for this

kind of SMPS, thanks to the absence of post regulators.

Table 3. shows the same measurement done during the HDD spin-up, which means higher

current from the 12V output, while the other output currents are not changed.

Table 3.

Output Voltage Measurement at HDD SPIN-UP

As clearly visible in this table, the output voltages are still within the given tolerance. The

heavier load does not affect efficiency. Please note that that the total output power of Table 3. is

the so-called "electrical power", not the "thermal power". Therefore, the circuit has been

designed to deliver the "electrical power" for a short time only - typically the HDD spin-up has

at 115Vac - 60Hz

at 230Vac - 50Hz

Voltage [V] Current [A]

Deviation

Voltage [V] Current [A]

Deviation

11.70

1.9

-2.50%

OK

11.6

1.9

-3.33%

OK

1.81

1.7

0.56

OK

1.82

1.7

1.11%

OK

4.82

2.4

-3.60%

OK

4.82

2.4

-3.60%

OK

3.28

0.5

-0.61%

OK

3.28

0.5

-0.61%

OK

at 115Vac - 60Hz

at 230Vac - 50Hz

Voltage [V] Current [A]

Deviation

Voltage [V] Current [A]

Deviation

11.51

2.9

-4.08%

OK

11.46

2.9

-4.50%

OK

1.81

1.7

0.56%

OK

1.82

1.7

1.11%

OK

4.77

2.4

-4.60%

OK

4.80

2.4

-4.00%

OK

3.3

0.5

-0.00%

OK

3.29

0.5

-0.30%

OK

Vin= 115Vac

lin= 0.75Arms

Pin= 49W

EFF.= 78.6%

Vin= 230Vac

lin= 0.44Arms

Pin= 47.6W

EFF.= 80.6%

Pout=38.52W

Pout=38.34W

Vin= 115Vac

lin= 0.93Arms

Pin= 64.5W

EFF.= 76.8%

Vin= 230Vac

lin= 0.55Arms

Pin= 61.2W

EFF.= 80.9%

Pout=49.55W

Pout=49.49W