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L6711

Figure 9. Remote Buffer Connections

8

VOLTAGE POSITIONING

Output voltage positioning is performed by selecting the reference DAC and by programming the different

ations depending on the sensed current (Droop Function) as well as offsets for the regulation.

Moreover, the embedded Remote Buffer allows to precisely programming the output voltage offsets and

variations by recovering the voltage drops across distribution lines.

Figure 10. Voltage Positioning and Droop Function

8.1

DROOP FUNCTION

Droop function allows the device to satisfy the requirements of high performance microprocessors, reduc-

ing the size and the cost of the output capacitor. 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 figure 4-right, the ESR drop is present in any case, but using the droop function the

total deviation of the output voltage is minimized.

RB used (up to ±0.5% Accuracy)

RB Not Used (Precision worsened)

VID

FB

COMP

VSEN

64k

FBR

FBG

64k

To Vcore

(Remote Sense)

VID

FB

COMP

VSEN

64k

FBR

FBG

64k

To Vcore

V

OUT

VID

R

FB

I

FB

⋅

–

VID

R

FB

I

DROOP

I

OFFSET

I

TC

–

±

()

⋅

–

==

ESR DROP

RESPONSE WITHOUT DROOP

RESPONSE WITH DROOP

VID

FB

COMP

I

FB

VSEN

64k

FBR

FBG

64k

To Vcore

(Remote Sense)