Data Sheet 17 Rev. 1.2, 2009-11-09
TLE4253
Application Information
Figure 4 Application circuit: Output voltage V
Q
lower than reference voltage V
REF
In order to obtain a lower output voltage V
Q
at the tracker output than the reference voltage V
REF
, a voltage divider
according to Figure 4 has to be used. The output voltage
V
Q
then calculates:
With a given reference voltage
V
REF
, the desired output voltage V
Q
and the resistor value R1
ADJ
, the resistor value
for
R2
ADJ
is given by:
Taking into consideration also the effect of the internal EN/ADJ pull-down resistor, the external resistor divider’s
R2
ADJ
has to be selected to:
EN/
ADJ
I
Q
GND
TLE 4253 G
8
5
1
µC, e.g. C167
VDD
I/O
Main µC supply, e.g.
TLE4271-2
TLE4278
TLE4470
etc.
IQ
GND
VBAT
VQ < VREF
R1
ADJ
R2
ADJ
VREF
FB
4
2, 3, 6, 7
V
Q
V
REF
R2
ADJ
R1
ADJ
R2
ADJ
+
--------------------------------------- -
⋅=
R2
ADJ
R1
ADJ
V
Q
V
REF
V
Q
–
---------------------------
⋅=
R2
ADJ select,
R2
ADJ
R
PullDown min,
⋅
R
PullDown min,
R2
ADJ
–
--------------------------------------------------------- -
=
