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AS7620

Datasheet - D e t a i l e d D e s c r i p t i o n

formula:

(EQ 1)

Where:

Rh is the high side resistor of the output divider

Rl is the resistor of the output divider

Note:

It is suggested to select resistors in the range of hundreds of k

Ω in order to limit the current consumption.

8.5 Current Limit

The current is sensed during the on time of the internal PMOS. Three different current limit thresholds can be selected by the ILIM pin:

1. 240mA (typ) ILIM shorted to GND

3. 1000mA (typ) ILIM floating

This threshold is intended as peak current limit. If the current reaches the threshold during the on time, the PMOS is turned off and it will be

ILIM/2.

8.6 Switching Frequency

to page 8) – the converter always works in DCM and, normally, the peak current into the inductor is the CL threshold (ILIM). The average of the

inductor current must be equal to the output current. The following formula provides the relationship between inductor current and output current:

(EQ 2)

(EQ 3)

V

OUT

V

REF

1

Rh

Rl

-------

+









•

=

1

Tsw

----------

1

2

---

ILIM

2

L

•

V

IN

•

V

IN

V

OUT

–

(

) V

OUT

•

--------------------------------------------------

•

•

Fsw

2

I

OUT

•

V

IN

V

OUT

–

(

) V

OUT

•

•

ILIM

2

L

•

V

IN

•

----------------------------------------------------------------------------

=

Fsw vs. Iout

0

50

100

150

200

250

300

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

Iout (A)