L6701TR STMicroelectronics, L6701TR Datasheet - Page 20

• Manufacturer Part Number: L6701TR
• Description: IC CTRLR 3PH VR10/9/K8 PWRSSO-36
• Manufacturer: STMicroelectronics

Specifications of L6701TR

• Applications: Controller, Intel VR9, VR10, K8
• Voltage - Input: 12V
• Number Of Outputs: 3
• Voltage - Output: 0.8 ~ 1.85 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 36-PowerSOIC
• Output Voltage: 0.8 V to 1.85 V
• Output Current: 1.5 A
• Switching Frequency: 110 KHz
• Mounting Style: SMD/SMT
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: 0 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-6108-2

9 Current Sharing Loop and Current Reading
9
9.1
9.2
20/44
Current Sharing Loop and Current Reading
Current Sharing Loop
L6701 embeds two separate Current Reading circuitries used to perform Current Sharing and
OCP through ISENx pins and Voltage Positioning (Droop Function) through CS+ and CS- pins
(See
Current sharing control loop and connections are reported in
the I
phase and the information about the average current I
device. The error between the read current I
a voltage that with a proper gain is used to adjust the duty cycle whose dominant value is set by
the voltage error amplifier in order to equalize the current carried by each phase.
Current Reading for Current Sharing
The current flowing trough each phase is read using the voltage drop across the low side
MOSFETs R
current. The trans-conductance ratio is issued by the external resistor R
chip between I
The current sense circuit tracks the current information for a time T
middle of the LS conduction time and holds the tracked information during the rest of the
period. The current that flows from the I
perform current sharing and OCP and it is given by:
where R
conductance resistor connected between the ISENx pins and the LS Drain; I
current carried by the relative phase and I
internally. R
details.
Figure 6.
SENx
AVG
Section
DS(on)
pins is converted into a current I
ISENx
Current Sharing Loop and Current Reading Connections
DS(on)
10).
SENx
is the ON resistance of the low side MOSFET and R
is designed according to the Over Current Protection: see
or across a sense resistor in its series and it is internally converted into a
and the reading point (usually the LS MOSFET Drain).
I
I
I
From EA
I
INFO1
AVG
INFO2
INFO3
I
ISENx
=
R
----------------- I
R
SENx
dsO N
ISEN
INFOx
INFOx
INFOx
pin is the current information used by the device to
⋅
PWM1 Out
PWM2 Out
PWM3 Out
proportional to the current delivered by each
PHASEx
is the current information signal reproduced
and the reference I
AVG
=
= ΣI
I
INFO x
Figure
I
ISENx
INFOx
LGATEx
ISENx
TRACK
ISEN
/ 3 is internally built into the
6: the current read through
AVG
ISEN
is the trans-
is then converted into
centered in the
R
Section 13.6
ISEN
placed outside the
PHASEx
is the
L6701
I
PHASEx
for