Datasheet

TLE 6389
Datasheet Rev. 2.1 28 2007-08-13
Figure 3 Application circuit TLE6389-2 GV
7.3 Output voltage at adjustable version - feedback divider
The output voltage is sensed either by an internal voltage divider connected to the VOUT
pin (TLE6389-2
GV50 and TLE6389-3 GV50, fixed 5V versions) or an external divider
from the Buck output voltage to the FB pin (TLE6389-2
GV, adjustable version). Pin
VOUT has to be connected always to the Buck converter output regardless of the
selected output voltage for the -2GV version.
To determine the resistors of the feedback divider for the desired output voltage V
OUT
at
the TLE6389-2
GV select R
FB2
between 5kΩ and 500kΩ and obtain R
FB1
with the
following formula:
V
FB
is the threshold of the error amplifier with its value of typical 1.25V which shows that
the output voltage can be adjusted in a range from 1.25V to 15V. However the integrated
Reset function will only be operational if the output voltage level is adjusted to >7V.
Also the current consumption will be increased in PFM mode in the range between
1.25V and 7V.
M1
D1
C
OUT
=
100 µF
V
OUT
C
BDS
=
220 nF
V
IN
L
1
= 47 µH
TLE6389-2 GV
GDRV
BD S
VOU T
GNDEN ABL E
C
IN1
=
100 µF
ON OFF
CS
R
SENSE
=
47mΩ
M1: Infineon BSO613SPV
Inf ineon BSP613P
D1: Mot orola MBRD360
L1: EPCOS B82479-A1473-M
Coilcraft DO3340P-473
C
IN1
: Electrolythic
C
IN2
: Ceramic
C
OU T
: Low ESR Tant alum
R
SI1
=
400kΩ
C
IN2
=
220nF
R
SI2
=
100kΩ
FB
SO
RO
SYN C
COMP
R
FB2
=
47kΩ
11
13
7
SI
VS
14 12 3
9
2
8
10451
SI_ GN D
6
t o e. g. 5V rail
R
SO
=
R
RO
=
20kΩ
to µC
to µC
R
FB1
=
330kΩ
680 Ω
2. 2nF
R
FB1
R
FB2
V
OUT
V
FB th
,
---------------- 1–


⋅=