TLE6389_07 datasheet(30/38 Pages) INFINEON

No. de pieza	TLE6389

Descripción Electrónicos	Step-Down DC/DC Controller

PDF	38 Pages

Scroll/Zoom	100%

Fabricante Electrónico	INFINEON [Infineon Technologies AG]

Página de inicio	http://www.infineon.com

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30 / 38 page

TLE 6389

Datasheet Rev. 2.1

2007-08-13

Figure 4

Reset timing

7.7

100% duty-cycle operation and dropout

The TLE 6389 operates with a duty cycle up to 100%. This feature allows to operate with

the lowest possible drop voltage at low battery voltage as it occurs at cold cranking. The

MOSFET is turned on continuously when the supply voltage approaches the output

voltage level, conventional switching regulators with less than 100% duty cycle would fail

in that case.

The drop- or dropout voltage is defined as the difference between the input and output

voltage levels when the input is low enough to drop the output out of regulation. Dropout

depends on the MOSFET drain-to-source on-resistance, the current-sense resistor and

the inductor series resistance. It is proportional to the load current:

VOUT, RT

FB,RT

< t

thermal

shutdown

under

voltage

over

load

VOUT

Vdrop

ILOAD RDS ON

()PMOS

RSENSE RINDUCTANCE

()

⋅

TLE6389 Datasheet(PDF) 30 Page - Infineon Technologies AG