MIC4680

Micrel

MIC4680

6

June 2000

Switching Frequency Foldback

TIME

Normal

Operation

Short

Circuit

Operation

200kHz

60kHz

Load Transient

V

V

I

TIME (100ms/div.)

5.1V

5V

1A

0A

Functional Characteristics

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

1.5

0

5

10

15

20

25

30

35

INPUT VOLTAGE (V)

Safe

Operating Area

V

T

Demonstration

board layout

Minimum

Current Limit

Note

Frequency Foldback

The MIC4680 folds the switching frequency back during a hard

short-circuit condition to reduce the energy per cycle and

protect the device.

Note. For increased output current, see “Applications Information:

Increasing the Maximum Output Current” and Figure 3.