Electrical performance

AN2840

12/19

to be calculated as the average of the efficiency at 25%, 50%, 75% and 100% of rated load.

The input power without load has also been measured and as indicated in Table 3, the no-

load consumption is always below 100 mW. Therefore, this adapter using the VIPER17HN

meets the most restrictive worldwide standards regarding efficiency and power consumption

at no-load (European Code of Conduct, adapter for mobile handheld battery-driven

applications, starting from 1st January 2011: <150 mW).

Output voltage regulation during no-load operation is always good, and output voltage

delivered is always within the specification. Neither output voltage drops nor abnormal turn-

off and restarting cycles are present during no-load operation or load transients.

4.2

V-I output characteristics and cable drop compensation

Figure 16 shows the V-I output characteristics at the PCB output pads and at end of the

significantly.

Due to the high performance of the TSM1052, in the constant current region the output

voltage drops down to 1.5 V (1.3 V at the end of the output cable) while perfectly regulating

the output current.

A further decrease in the output load impedance, as in the case of a short-circuit, causes an

additional decrease in the output voltage that is insufficient to power the TSM1052. This

results in a hiccup working mode with a very low average output current.

Figure 16.

Table 3.

No-load consumption

5.07

5.07

5.07

5.07

5.07

Pin [mW]

48

49.5

52

81.5

95