l6706 STMicroelectronics, l6706 Datasheet - Page 23

• Manufacturer Part Number: l6706
• Description: Vr11.1 Single Phase Controller With Integrated Driver
• Manufacturer: STMicroelectronics

L6706
9
Droop thermal compensation
Current sense element (DCR inductor) has a non-negligible temperature variation. As a
consequence, the sensed current is subjected to a measurement error that causes the
regulated output voltage to vary accordingly (when droop function is implemented).
To recover from this temperature related error, NTC resistor can be added into feedback
compensation network, as shown in
The output voltage is then driven by the following relationship (neglecting the OFFSET
voltage term):
where R
NTC resistor.
Considering the relationships between I
where T is the temperature.
If the inductor temperature increases the DCR inductor increases and NTC resistor
decreases. As a consequence the equivalent R
output voltage respect to temperature variation.
NTC resistor must be placed as close as possible to the sense element (phase inductor).
Figure 8.
FB
is the equivalent feedback resistor and it depends on the temperature through
NTC connections for DC load line thermal compensation
GND DROP
RECOVERY
To GND_core
(Remote Sense)
V
PROG
V
OUT
FBG
FBG
[
( ,
T I
To VCC_core
(Remote Sense)
OUT
Doc ID 15698 Rev 1
V
OUT
)
]
=
Figure 8.
=
V
V
DROOP
PROG
PROG
R
FB
NTC
–
–
⎛
⎝
and the I
I
FB
OS
R
(
R
FB2
R
FB
R
FB
resistor decreases keeping constant the
FB3
T [ ]
⋅
I
DROOP
R
I
FB1
DROOP
⋅
OUT
DCR T [ ]
--------------------- - I
Rg
, the output voltage results:
V
Droop thermal compensation
REF
)
FB
R
F
⋅
ERROR AMPLIFIER
OUT
C
C
P
F
⎞
⎠
COMP
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