HIP6302VCB-T Intersil, HIP6302VCB-T Datasheet - Page 14

• Manufacturer Part Number: HIP6302VCB-T
• Description: IC CTRLR PWM MULTIPHASE 16-SOIC
• Manufacturer: Intersil

Specifications of HIP6302VCB-T

• Pwm Type: Controller
• Number Of Outputs: 4
• Frequency - Max: 336kHz
• Voltage - Supply: 4.75 V ~ 5.25 V
• Buck: Yes
• Boost: No
• Flyback: No
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: No
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 16-SOIC (3.9mm Width)
• Frequency-max: 336kHz
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Duty Cycle: -

Droop, Selection of R
The average of the currents detected through the R
resistors is also steered to the FB pin. There is no DC return
path connected to the FB pin except for R
current creates a voltage drop across R
increases the apparent V
current, causing the system to decrease V
balance at the FB pin. This is the desired “droop” voltage
used to maintain V
conditions.
With a high dv/dt load transient, typical of high performance
microprocessors, the largest deviations in output voltage
occur at the leading and trailing edges of the load transient.
In order to fully utilize the output-voltage tolerance range, the
output voltage is positioned in the upper half of the range
when the output is unloaded and in the lower half of the
range when the controller is under full load. This droop
compensation allows larger transient voltage deviations and
thus reduces the size and cost of the output filter
components.
R
the normal full load current 50µA applied through the R
resistor (or at a different full load current if adjusted as in
“Overcurrent, Selecting RISEN” on page 13).
For a Vdroop of 80mV, R
The AC feedback components, R
relation to R
Current Balancing
The detected currents are also used to balance the phase
currents.
Each phase’s current is compared to the average of all
phase currents, and the difference is used to create an offset
in that phase’s PWM comparator. The offset is in a direction
to reduce the imbalance.
The balancing circuit can not make up for a difference in
r
higher r
reduced.
Figures 10 and 11 show the inductor current of a 2-phase
system without and with current balancing.
Inductor Current
The inductor current in each phase of a multiphase buck
converter has two components. There is a current equal to
the load current divided by the number of phases (I
a sawtooth current, (I
sawtooth component is dependent on the size of the
inductors, the switching frequency of each phase, and the
values of the input and output voltage. Ignoring secondary
R
DS(ON)
IN
IN
should be selected to give the desired “droop” voltage at
=
Vdroop
DS(ON)
between synchronous rectifiers. If a FET has a
IN
⁄
.
(
, the current through that phase will be
50μA
CORE
)
P-P
) resulting from switching. The
IN
CORE
within limits under transient
IN
= 1.6kΩ
14
voltage with increasing load
FB
and Cc, are scaled in
IN
IN
. This drop
CORE
, so the average
to maintain
LT
HIP6301V, HIP6302V
HIP6301V, HIP6302V
ISEN
/n), and
(EQ. 3)
ISEN
effects, such as series resistance, the peak-to-peak value of
the sawtooth current can be described by Equation 4.
Where: V
Example: For V
Then I
The inductor, or load current, flows alternately from V
through Q
samples the on-state voltage drop across each Q
to indicate the inductor current in that phase. The voltage
drop is sampled 1/3 of a switching period, 1/F
I
P P
FIGURE 10. TWO CHANNEL MULTIPHASE SYSTEM
FIGURE 11. TWO CHANNEL MULTIPHASE SYSTEM
–
25
20
15
10
25
20
15
10
5
0
5
0
=
P-P
V
---------------------------------------------------------------- -
CORE
IN
1
= 4.3A
(
and from ground through Q
F
L ( ) F
V
V
SW
WITH CURRENT BALANCING DISABLED
WITH CURRENT BALANCING ENABLED
CORE
IN
(
L = value of the inductor
CORE
F
SW
= DC value of the output or V
= DC value of the input or supply voltage
= switching frequency
V
SW
IN
) V
L = 1.3µH,
) V
–
(
= 1.6V,
= 12V,
= 250kHz,
IN
2
CORE
)
2
. The controller
SW
ID
, after Q
2
voltage
transistor
May 5, 2008
IN
FN9034.3
(EQ. 4)
1
is