isl6307b Intersil Corporation, isl6307b Datasheet - Page 11

• Manufacturer Part Number: isl6307b
• Description: 6-phase Vr11 Pwm Controller With 8-bit Vid Code Capable Of Precision Rds On Or Dcr Differential Current Sensing For Applications In Which Supply Voltage Is Higher Than 5v
• Manufacturer: Intersil Corporation

PWM1, PWM2, PWM3, PWM4, PWM5, PWM6 - Pulse-
width modulation outputs. Connect these pins to the PWM
input pins of the Intersil driver IC. The number of active
channels is determined by the state of PWM3, PWM4,
PWM5 and PWM 6. Tie PWM3 to VCC to configure for
2-phase operation. Tie PWM4 to VCC to configure for
3-phase operation. Tie PWM5 to VCC to configure for
4-phase operation. Tie PWM6 to VCC to configure for
5-phase operation.
ISEN1+, ISEN1-; ISEN2+, ISEN2-; ISEN3+, ISEN3-;
ISEN4+, ISEN4-; ISEN5+, ISEN5-; ISEN6+, ISEN6- - The
ISEN+ and ISEN- pins are current sense inputs to individual
differential amplifiers. The sensed current is used as a
reference for channel balancing, protection, and regulation.
Inactive channels should have their respective current sense
inputs left open (for example, for 3-phase operation open
ISEN4+).
For DCR sensing, connect each ISEN- pin to the node
between the RC sense elements. Tie the ISEN+ pin to the
other end of the sense capacitor through a resistor, R
The voltage across the sense capacitor is proportional to the
inductor current. The sense current is proportional to the
output current, and scaled by the DCR of the inductor and
R
When configured for R
ISEN2-, ISEN3-, ISEN4-, ISEN5-, ISEN6- pins are grounded
at the lower MOSFET sources. The ISEN1+, ISEN2+,
ISEN3+, ISEN4+, ISEN5+, ISEN6+ pins are then held at a
virtual ground, such that a resistor connected between them,
and the drain terminal of the associated lower MOSFET, will
carry a current proportional to the current flowing through
that channel. The current is determined by the negative
voltage developed across the lower MOSFET’s R
which is the channel current scaled by R
VR_RDY - VR_RDY is used as an indication of the end of
soft-start with certain delay per Intel VR11. It is an open-
drain logic output that is low impedance until the soft-start is
completed. It will be pulled low again once the undervoltage
point is reached.
OFS - The OFS pin provides a means to program a DC
offset current for generating a DC offset voltage at the REF
input. The offset current is generated via an external resistor
and precision internal voltage references. The polarity of the
offset is selected by connecting the resistor to GND or VCC.
For no offset, the OFS pin should be left unterminated.
TCOMP - Temperature compensation scaling input. The
voltage sensed on the TM pin is utilized as the temperature
input to adjust ldroop and the overcurrent protection limit to
effectively compensate for the temperature coefficient of the
current sense element. To implement the integrated
temperature compensation, a resistor divider circuit is
needed with one resistor being connected from TCOMP to
VCC of the controller and another resistor being connected
ISEN
.
DS(ON)
11
current sensing, the ISEN1-,
DS(ON)
and R
DS(ON)
ISEN
ISEN
,
ISL6307B
.
.
from TCOMP to GND. Changing the ratio of the resistor
values will set the gain of the integrated thermal
compensation. When integrated temperature compensation
function is not used, connect TCOMP to GND.
OVP - The Overvoltage protection output indication pin. This
pin can be pulled to VCC and is latched when an overvoltage
condition is detected. When not used, keep this pin open.
IDROOP - The output pin of sensed average channel
current which is probational to load current. In the
application which does not require loadline, leave this pin
open. In the application which requires load line, connect
this pin to FB so that the sensed average current will flow
through the resistor between FB and VDIFF to create a
voltage drop which is probational to load current.
IOUT - IOUT has the same output as IDROOP with
additional OCP adjustment function. In actual application, a
resistor needs to be placed between IOUT and GND to
ensure the proper operation. The Voltage at IOUT pin will be
proportional to the load current. If the voltage is higher than
2V, ISL6307B will go into OCP mode, this means shut down
first and then hiccup. The additional OCP trip level can be
adjusted by changing the resistor value.
TM - TM is an input pin for VR temperature measurement.
Connect this pin through NTC thermistor to GND and a
resistor to 5V. The voltage at this pin is proportional to VR
temperature. ISL6307 monitor the VR temperature based
the voltage at TM pin and output VR_HOT and VR_FAN
control singles.
VR_HOT - An indication output pin of high VR temperature.
It is an open-drain logic output with low impedance. It will be
pulled high when measured VR temperature reaches certain
level.
VR_FAN - An indication output pin of VR temperature high
warning with open-drain logic. It will be pulled high when
measured VR temperature reaches certain level. VR_FAN
will be pulled to high before VR_HOT.
Operation
Multiphase Power Conversion
Microprocessor load current profiles have changed to the
point that the advantages of multiphase power conversion
are impossible to ignore. The technical challenges
associated with producing a single-phase converter which is
both cost-effective and thermally viable, have forced a
change to the cost-saving approach of multiphase. The
ISL6307B controller helps reduce the complexity of
implementation by integrating vital functions and requiring
minimal output components. The block diagrams on pages
4, 5, 6 and 7 provide top level views of multiphase power
conversion using the ISL6307B controller.
March 9, 2006
FN9225.0