ISL62882HRTZ Intersil, ISL62882HRTZ Datasheet - Page 25

• Manufacturer Part Number: ISL62882HRTZ
• Description: IC REG PWM 2PHASE BUCK 40TQFN
• Manufacturer: Intersil

Specifications of ISL62882HRTZ

• Applications: Controller, Intel IMVP-6.5™
• Voltage - Input: 5 V ~ 25 V
• Number Of Outputs: 1
• Voltage - Output: 0.0125 V ~ 1.5 V
• Operating Temperature: -10°C ~ 100°C
• Mounting Type: *
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

A VR with active droop function is a dual-loop system
consisting of a voltage loop and a droop loop which is a
current loop. However, neither loop alone is sufficient to
describe the entire system. The spreadsheet shows two
loop gain transfer functions, T1(s) and T2(s), that
describe the entire system. Figure 25 conceptually
shows T1(s) measurement set-up and Figure 26
conceptually shows T2(s) measurement set-up. The VR
senses the inductor current, multiplies it by a gain of
the load line slope, then adds it on top of the sensed
output voltage and feeds it to the compensator. T(1) is
measured after the summing node, and T2(s) is
measured in the voltage loop before the summing node.
The spreadsheet gives both T1(s) and T2(s) plots.
However, only T2(s) can be actually measured on an
ISL62882 regulator.
T1(s) is the total loop gain of the voltage loop and the
droop loop. It always has a higher crossover frequency
than T2(s) and has more meaning of system stability.
T2(s) is the voltage loop gain with closed droop loop. It
has more meaning of output voltage response.
Design the compensator to get stable T1(s) and T2(s)
with sufficient phase margin, and output impedance
equal or smaller than the load line slope.
25
ISL62882, ISL62882B
FIGURE 25. LOOP GAIN T1(s) MEASUREMENT SET-UP
FIGURE 26. LOOP GAIN T2(s) MEASUREMENT SET-UP
V IN
V in
LOOP GAIN =
LOOP GAIN=
DRIVER
DRIVER
Q1
GATE
Q1
GATE
MOD.
MOD.
Q2
CHANNEL A
CHANNEL B
CHANNEL B
CHANNEL A
Q2
COMP
ANALYZER
NETWORK
CHANNEL A
COMP
LOAD LINE SLOPE
ANALYZER
CHANNEL A
NETWORK
EA
L
LOAD LINE SLOPE
C OUT
EA
L
VID
C out
VID
EXCITATION OUTPUT
EXCITATION OUTPUT
V O
20
V o
I
O
20
Ω
o i
Ω
ISOLATION
TRANSFORMER
ISOLATION
TRANSFORMER
CHANNEL B
CHANNEL B
FN6890.3