out

out

in _ DC

in

V

I

I

V

´

=

´ h

in

lim

p

out _ max

out

V

(I

I / 2)

I

V

´

-

´ h

=

ú

û

ù

ê

ë

é

+

-

+

´

´

=

)

V

1

V

V

V

1

(

F

L

1

I

in

in

f

out

s

P

10

TPS61165

SLVS790D – NOVEMBER 2007 – REVISED APRIL 2016

www.ti.com

Product Folder Links: TPS61165

Submit Documentation Feedback

Copyright © 2007–2016, Texas Instruments Incorporated

9 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

9.1 Application Information

9.1.1 Maximum Output Current

The overcurrent limit in a boost converter limits the maximum input current and thus maximum input power for a

given input voltage. Maximum output power is less than maximum input power due to power conversion losses.

Therefore, the current limit setting, input voltage, output voltage and efficiency can all change maximum current

output. The current limit clamps the peak inductor current; therefore, the ripple has to be subtracted to derive

maximum dc current. The ripple current is a function of switching frequency, inductor value and duty cycle. The

following equations take into account of all the above factors for maximum output current calculation.

where

•

•

L = inductor value

•

•

•

(1)

where

•

•

•

η = efficiency

(2)

maximum output current is 150 mA in typical condition.

9.1.2 Inductor Selection

Selection of the inductor affects steady state operation as well as transient behavior and loop stability. These

factors make it the most important component in power regulator design. There are three important inductor

specifications, inductor value, DC resistance and saturation current. Considering inductor value alone is not

enough.

The inductor value determines the inductor ripple current. Choose an inductor that can handle the necessary

peak current without saturating, according to half of the peak-to-peak ripple current given by Equation 1, pause

the inductor DC current given by:

(3)