Application information

STLDC08

18/29

Doc ID 18476 Rev 1

Equation 6

Equation 7

The value of the peak current on the inductor is given by the following equation:

Equation 8

be expressed as follows:

Equation 9

The saturation current rating for the inductor should be checked at the maximum duty cycle

and maximum output current.

8.4

Inductor peak current limit

The value of the inductor peak current limit can be programmed either by using a sense

resistor or by using the RDSON of the main Power MOSFET.

The following equation gives the relationship between the peak current limit and the value of

the sense resistor:

Equation 10

The sense resistor value can be determined fixing the value of the inductor peak current

limit equal to twice the value of the inductor peak current in steady-state conditions.

MAX

LED

)

AVG

(

L

L

D

1

I

%

40

I

%

40

I

−

×

=

×

=

Δ

D

OUT

)

MIN

(

IN

MAX

V

V

V

1

D

+

−

=

2

I

I

I

L

)

AVG

(

L

)

PK

(

L

Δ

+

=

2

I

D

1

I

I

I

L

MAX

OUT

)

PK

(

L

)

SAT

(

L

Δ

+

−

=

>

SENSE

SENSE

SENSE

)

MAX

(

IN

R

1

.

0

R

V

I

=

=