Electrical characteristics

AN2487

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4.7

Characteristics of entire system

4.7.1

Output vs. input voltage

As can be seen from the figures below, there is almost no sensitivity to input voltage. This is

a characteristic common to all current-mode controlled converters.

4.7.2

Cross regulation

The following graphs should be self-explanatory.

Note that there is almost no variation with input voltage.

Figure 14.

Cross regulation, 42 V In, 12 V at

half load, 3.3 V load varied

Figure 15.

Cross regulation, 42 V In, 3.3 V at

half load, 12 V load varied

0

2

4

6

8

10

12

14

0

0.2

0.4

0.6

0.8

1

3.3V Load, Am ps

12V Output

3.3V Output

0

2

4

6

8

10

12

14

0

0.2

0.4

0.6

0.8

1

12V Load, Am ps

12V Output

3.3V Output

Figure 16.

Cross regulation, 50 V In, 12 V at

half load, 3.3 V load varied

Figure 17.

Cross regulation, 50 V In, 3.3 V at

half load, 12 V load varied

0

2

4

6

8

10

12

14

00.2

0.4

0.6

0.8

1

3.3V Load, Am ps

12V Output

3.3V Output

0

2

4

6

8

10

12

14

0

0.2

0.4

0.6

0.8

1

12V Load, Am ps

12V Output

3.3V Output

Figure 18.

Cross regulation, 57 V In, 12 V at

half load, 3.3 V load varied

Figure 19.

Cross regulation, 57 V In, 3.3 V at

half load, 12 V load varied

0

2

4

6

8

10

12

14

00.2

0.4

0.6

0.8

1

3.3V Load, Am ps

12V Output

3.3V Output

0

2

4

6

8

10

12

14

00.2

0.4

0.6

0.8

1

12V Load, Am ps

12V Output

3.3V Output