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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

has to be tuned according to the following 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.

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 turned on again only when the current approaches 0A and the feedback voltage is equal or

Switching Frequency

process. As described in the Regulation (refer 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)