ISL6316IRZ-T Intersil, ISL6316IRZ-T Datasheet - Page 15

• Manufacturer Part Number: ISL6316IRZ-T
• Description: IC CTRLR PWM 4PHASE ENH 40-QFN
• Manufacturer: Intersil

Specifications of ISL6316IRZ-T

• Pwm Type: Voltage Mode
• Number Of Outputs: 1
• Frequency - Max: 275kHz
• Duty Cycle: 66.7%
• 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: -40°C ~ 85°C
• Package / Case: 40-VFQFN, 40-VFQFPN
• Frequency-max: 275kHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

or the integrated temperature compensation function of
ISL6316 should be utilized. The integrated temperature
compensation function is described in the Temperature
Compensation section.
Channel-Current Balance
The sensed current I
together and divided by the number of active channels. The
resulting average current I
load current. Channel current balance is achieved by
comparing the sampled current of each channel to the
average current to make an appropriate adjustment to the
WPM duty cycle of each channel. Intersil’s patented current-
balance method is illustrated in Figure 7. In the figure, the
average current combines with the channel 1 current I
create an error signal I
the pulse width commanded by V
unbalance and force I
error signal correction is applied to each active channel.
NOTE: *CHANNELS 3 AND 4 ARE OPTIONAL.
Channel current balance is essential in achieving the thermal
advantage of multiphase operation. With good current
balance, the power loss is equally dissipated over multiple
devices and a greater area.
Voltage Regulation
The compensation network shown in Figure 8 assures that
the steady-state error in the output voltage is limited only to
the error in the reference voltage (output of the DAC) and
offset errors in the OFS current source, remote-sense and
error amplifiers. Intersil specifies the guaranteed tolerance of
the ISL6316 to include the combined tolerances of each of
these elements.
The output of the error amplifier, V
sawtooth waveform to generate the PWM signals. The PWM
signals control the timing of the Intersil MOSFET drivers and
regulate the converter output to the specified reference
voltage. The internal and external circuitry which control
voltage regulation is illustrated in Figure 8.
FIGURE 7. CHANNEL-1 PWM FUNCTION AND CURRENT-
V
COMP
FILTER
BALANCE ADJUSTMENT
+
I
ER
F(JΩ)
-
+
I
1
n
ER
from each active channel are summed
ER
-
I
AVG
toward zero. The same method for
. The filtered error signal modifies
AVG
SAWTOOTH SIGNAL
15
÷ N
provides a measure of the total
COMP
COMP
+
-
to correct any
, is compared to the
Σ
PWM1
I
I
I
4
3
2
*
*
1
to
ISL6316
The ISL6316 incorporates an internal differential remote-sense
amplifier in the feedback path. The amplifier removes the
voltage error encountered when measuring the output voltage
relative to the local controller ground reference point resulting in
a more accurate means of sensing output voltage. Connect the
microprocessor sense pins to the non-inverting input, VSEN,
and inverting input, RGND, of the remote-sense amplifier. The
remote-sense output, V
of the error amplifier through an external resistor.
A digital-to-analog converter (DAC) generates a reference
voltage based on the state of logic signals at pins VID7
through VID0. The DAC decodes the 6-bit logic signal (VID)
into one of the discrete voltages shown in Table 1. Each VID
input offers a 45μA pull-up to an internal 2.5V source for use
with open-drain outputs. The pull-up current diminishes to
zero above the logic threshold to protect voltage-sensitive
output devices. External pull-up resistors can augment the
pull-up current sources if case leakage into the driving device
is greater than 45μA.
FIGURE 8. OUTPUT VOLTAGE AND LOAD-LINE
R
FB
EXTERNAL CIRCUIT
V
V
OUT
OUT
+
-
V
DROOP
C
R
REF
-
+
C
REGULATION WITH OFFSET ADJUSTMENT
R
C
REF
C
IDROOP
RGND
COMP
VDIFF
VSEN
DAC
REF
DIFF
FB
, is connected to the inverting input
ISL6316 INTERNAL CIRCUIT
I
AVG
DIFFERENTIAL
REMOTE-SENSE
AMPLIFIER
ERROR AMPLIFIER
+
-
+
-
December 12, 2006
V
COMP
FN9227.1