AN2840

Electrical performance

13/19

This circuit behavior is present due to a design that uses the output voltage to power the

even with a very small output voltage.

This application implements a simple circuit which compensates the voltage drop on the

output cable. The effect can be noted in Figure 16 and Table 4, which show the output

voltage measured at the output connector, after the output cable in different load conditions.

With the cable drop compensation (CDC) the output voltage is nearly constant, while without

CDC the output voltage drops down to 4.87 V (about -3.9%) at maximum load.

deviations are negligible (a few millivolts).

Figure 17.

Output voltage at output connector with and without CDC

Table 4.

Output voltage at output connector

0

0.2

0.4

0.6

0.8

1

5.07

5.07

5.07

5.07

5.06

5.08

5.12

5.03

4.99

4.95

4.91

4.87