ISL62882HRTZ Intersil, ISL62882HRTZ Datasheet - Page 19

• 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

Protections
The ISL62882 provides overcurrent, current-balance,
undervoltage, overvoltage, and over-temperature
protections.
The ISL62882 determines overcurrent protection (OCP)
by comparing the average value of the droop current
I
declares OCP when I
120µs. A resistor R
programs the OCP current source threshold, as well as
the overshoot reduction function in 1-phase
configuration, as Table 4 shows. It is recommended to
use the nominal R
R
internal OCP threshold accordingly. It remembers the
R
POR threshold.
The default OCP threshold is the value when R
populated. It is recommended to scale the droop current
I
approximately the desired OCP level, then use R
fine tune the OCP level if necessary.
For overcurrent conditions above 2.5x the OCP level, the
PWM outputs will immediately shut off and PGOOD will
go low to maximize protection. This protection is also
referred to as way-overcurrent protection or fast-
overcurrent protection, for short-circuit protections.
The ISL62882 monitors the ISEN pin voltages to
determine current-balance protection. If the ISEN pin
voltage difference is greater than 9mV for 1ms, the
controller will declare a fault and latch off.
The ISL62882 will declare undervoltage (UV) fault and
latch off if the output voltage is less than the VID set
value by 300mV or more for 1ms. It’ll turn off the PWM
outputs and de-assert PGOOD.
The ISL62882 has two levels of overvoltage protections.
The first level of overvoltage protection is referred to as
PGOOD overvoltage protection. If the output voltage
exceeds the VID set value by +200mV for 1ms, the
ISL62882 will declare a fault and de-assert PGOOD.
(kΩ)
MIN
droop
droop
320
210
155
104
comp
comp
78
62
45
TABLE 4. ISL62882 R
NOMINAL
with an internal current source threshold. It
such that the default OCP threshold gives
value at the beginning of start-up, and sets the
value until the VR_ON signal drops below the
R
(kΩ)
none
400
235
165
120
comp
85
66
50
(kΩ)
comp
MAX
none
480
260
175
136
92
70
55
comp
droop
value. The ISL62882 detects the
2-PHASE
CONFIG.
OCP THRESHOLD
from the COMP pin to GND
37.33
19
45.3
41.3
38.7
42.7
is above the threshold for
40
36
44
comp
(µA)
PROGRAMABILITY
1-PHASE CONFIG.
22.7
20.7
22.7
20.7
20
18
20
18
ISL62882, ISL62882B
OVERSHOOT
REDUCTION
FUNCTION
comp
Disabled
Enabled
comp
is not
to
Overcurrent
Way-Overcurrent
(2.5xOC)
Overvoltage
+200mV
Undervoltage -
300mV
Phase Current
Unbalance
Overvoltage 1.55V
Over-Temperature
The ISL62882 takes the same actions for all of the above
fault protections: de-assertion of PGOOD and turn-off of
the high-side and low-side power MOSFETs. Any residual
inductor current will decay through the MOSFET body
diodes. These fault conditions can be reset by bringing
VR_ON low or by bringing V
When VR_ON and V
levels, a soft-start will occur.
The second level of overvoltage protection is different.
If the output voltage exceeds 1.55V, the ISL62882 will
immediately declare an OV fault, de-assert PGOOD, and
turn on the low-side power MOSFETs. The low-side
power MOSFETs remain on until the output voltage is
pulled down below 0.85V when all power MOSFETs are
turned off. If the output voltage rises above 1.55V
again, the protection process is repeated. This behavior
provides the maximum amount of protection against
shorted high-side power MOSFETs while preventing
output ringing below ground. Resetting VR_ON cannot
clear the 1.55V OVP. Only resetting V
1.55V OVP is active all the time when the controller is
enabled, even if one of the other faults have been
declared. This ensures that the processor is protected
against high-side power MOSFET leakage while the
MOSFETs are commanded off.
The ISL62882 has a thermal throttling feature. If the
voltage on the NTC pin goes below the 1.18V OT
threshold, the VR_TT# pin is pulled low indicating the
need for thermal throttling to the system. No other
action is taken within the ISL62882 in response to NTC
pin voltage.
Table 5 summarizes the fault protections.
FAULT TYPE
TABLE 5. FAULT PROTECTION SUMMARY
PROTECTION
Immediately Low-side
DURATION
DD
BEFORE
FAULT
120µs
<2µs
return to their high operating
1ms
DD
below the POR threshold.
PROTECTION
PWM tri-state,
PGOOD
latched low
MOSFET on
until
<0.85V, then
PWM tri-state,
PGOOD
latched low.
1ms
ACTION
DD
Vcore
will clear it. The
VR_ON
toggle or
VDD
toggle
VDD
toggle
N/A
FAULT
RESET
FN6890.3