L6713A STMicroelectronics, L6713A Datasheet - Page 52

• Manufacturer Part Number: L6713A
• Description: IC CTRLR 2/3PH W/DRIVERS 64-TQFP
• Manufacturer: STMicroelectronics

Specifications of L6713A

• Applications: Controller, Intel VR10, VR11, AMD CPU
• Voltage - Input: 12V
• Number Of Outputs: 3
• 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
• Output Current: 2 A
• Mounting Style: SMD/SMT
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: 0 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

System control loop compensation
21
52/64
System control loop compensation
The control loop is composed by the current sharing control loop
average current mode control loop. Each loop gives, with a proper gain, the correction to the
PWM in order to minimize the error in its regulation: the current sharing control loop
equalize the currents in the inductors while the average current mode control loop fixes the
output voltage equal to the reference programmed by VID.
diagram of the system control loop.
The system control loop is reported in
the DROOP pin flows into R
read current.
Figure 25. Main control loop
The system can be modeled with an equivalent single phase converter which only difference
is the equivalent inductor L/N (where each phase has an L inductor). The control loop gain
results (obtained opening the loop after the COMP pin):
Where:
●
●
●
●
●
●
●
DCR is the Inductor parasitic resistance;
function;
Z
and the applied load R
Z
Z
A(s) is the error amplifier gain;
amplitude and has a typical value of 3 V.
PWM
P
F
L
R
(s) is the parallel of the N inductor impedance;
(s) is the compensation network impedance;
(s) is the impedance resulting by the parallel of the output capacitor (and its ESR)
(PHASE2 Only applies when using 3-PHASE Operation)
DROOP
=
CURRENT SHARING
4
-- -
5
=
CORRECTION
DUTY CYCLE
⋅
DCR
------------ - R
------------------ -
ΔV
1 / 5
1 / 5
1 / 5
Rg
V
G
OSC
IN
LOOP
⋅
FB
s ( )
is the PWM transfer function where ΔV
O
is the equivalent output resistance determined by the droop
FB
;
=
implementing the dependence of the output voltage from the
–
-------------------------------------------------------------------------------------------------------------------
[
I
I
I
INFO1
INFO2
INFO3
Z
P
s ( )
PWM Z
Figure
+
PWM3
PWM2
PWM1
Z
4 / 5
L
⋅
s ( )
ERROR AMPLIFIER
26. The current information I
F
]
COMP
s ( )
⋅
Z
--------------
⋅
A s ( )
F
(
R
s ( )
DROOP
+
L3
L2
L1
Z
⎛
⎝
F
1
(s)
Figure 25
+
+
----------- -
A s ( )
Z
1
FB
P
V
s ( )
OSC
REF
⎞ R
⎠
(See Figure
⋅
)
is the oscillator ramp
shows the block
FB
DROOP
I
DROOP
C
OUT
DROOP
Z
FB
(s)
9) and the
R
OUT
sourced by
L6713A