L6714 STMicroelectronics, L6714 Datasheet - Page 37

• Manufacturer Part Number: L6714
• Description: IC CTRLR 4PH W/DRIVERS 64-TQFP
• Manufacturer: STMicroelectronics

Specifications of L6714

• Applications: Controller, Intel VR10, VR11, AMD CPU
• Voltage - Input: 12V
• Number Of Outputs: 4
• Voltage - Output: 0.3 ~ 1.6 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 64-TQFP Exposed Pad, 64-eTQFP, 64-HTQFP, 64-VQFP
• Mounting Style: SMD/SMT
• Case: QFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

L6714
12.1
Droop function (Optional)
This method "recovers" part of the drop due to the output capacitor ESR in the load
transient, introducing a dependence of the output voltage on the load current: a static error
proportional to the output current causes the output voltage to vary according to the sensed
current.
As shown in
the total deviation of the output voltage is minimized. Moreover, more and more high-
performance CPUs require precise load-line regulation to perform in the proper way.
DROOP function is not then required only to optimize the output filter, but also beacomes a
requirement of the load.
Connecting DROOP pin and FB pin together, the device forces a current I
proportional to the read current, into the feedback resistor R
regulation dependence. Since I
phases, the output characteristic vs. load current is then given by:
Where R
I
The whole power supply can be then represented by a "real" voltage generator with an
equivalent output resistance R
designed according to the R
Droop function is optional, in case it is not desired, the DROOP pin can be disconnected
from the FB and an information about the total delivered current becomes available for
debugging, and/or current monitoring. When not used, the pin can be shorted to SGND.
Figure 11. Voltage positioning (left) and droop function (right)
OUT
DROOP
V
is the output current of the system.
OUT
SENSE
=
FB
V
Figure
REF
is the chosen sensing element resistance (Inductor DCR or LS R
V
REF
–
R
R
R
FB
F
11, the ESR drop is present in any case, but using the droop function
FB
COMP
C
I
F
DROOP
DROOP
DROOP
VSEN
DROOP
=
R
FB
specifications as follow:
V
REF
and a voltage value of V
=
depends on the current information about the three
R
64k
–
DROOP
64k
R
FB
FBR
(Remote Sense)
To Vcore
R
---------------------
SENSE
---------------------
R
Rg
FBG
SENSE
Rg
I
OUT
FB
V
REF
V
V
NOM
MAX
implementing the load
MIN
=
RESPONSE WITHOUT DROOP
. R
V
RESPONSE WITH DROOP
REF
FB
resistor can be also
Voltage positioning
–
ESR Drop
R
DROOP
DROOP
,
dsON
I
OUT
) and
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