IR3720MTRPBF International Rectifier, IR3720MTRPBF Datasheet - Page 12

• Manufacturer Part Number: IR3720MTRPBF
• Description: IC POWER SUPPLY MONITOR 10-DFN
• Manufacturer: International Rectifier
• Series: TruePower™r

Specifications of IR3720MTRPBF

• Package / Case: 10-DFN
• Mounting Type: Surface Mount
• Current - Supply: 480µA
• Voltage - Supply: 3.135 V ~ 3.465 V
• Operating Temperature: 0°C ~ 125°C
• Applications: Power Supply Monitor
• Voltage - Input: -
• Input Voltage: 3.3V
• No. Of Outputs: 1
• Supply Voltage Range: 3.135V To 3.465V
• No. Of Pins: 10
• Operating Temperature Range: 0°C To +125°C
• Filter Terminals: SMD
• Input Voltage Primary Max: 3.3V
• Rohs Compliant: Yes
• Frequency: 400kHz
• Package: 10 Lead 3x3 DFN
• Vk Range: 0.5V - 1.8V
• Bias Supply Voltage: +3.3V +/-5%
• Junction Temperature: 0oC to 125oC
• Pbf: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Input: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

TYPICAL 2-PHASE DCR-SENSING APPLICATION
The IR3720 is capable of monitoring power in a
multiphase converter. A two-phase circuit is shown
below. The voltage output of any phase is equal to
that of any and every other phase, and monitored at
VO as before.
Output current is the sum of the two inductor currents
(I
function for multiphase sensing. The voltage on R
due to I
Likewise, the voltage on R
The current through R
currents is I
Page 12 of 20
L1
+ I
L2
L1
). Superposition is used to derive the transfer
I
CS
is
I
CS
I
=
L
Multiphase
L
Converter
2
1
. From the two equations above
R
⋅
⋅
DCR
CS
DCR
I
L
1
1
R
DCR
Phase 1
CS
1
Phase 2
2
Return
Power
⋅
⋅
CS2
2
R
R
1
+
R
CS
CS
CS
R
due to both inductor
(
1
CS2
(
3
CS
R
R
+
3
+
CS
CS
1
+
(
R
(
due to I
R
2
R
I
2
CS
CS
L
||
CS
||
2
3
R
2
R
DCR
2
+
CS
||
CS
||
R
R
R
Figure 4Two Phase DCR Sensing Circuit
R
3
CS1
1
R
CS3
I
L2
CS
)
CS
L2
)
I
2
L1
CS
R
L
L
2
is
3
1
CS
R
)
)
CS
1
www.irf.com
3
C
R
CS1
CS2
C
DCR
DCR
CS2
CS2
1
2
RTN
If DCR
simplified to
Full scale I
which yields 256 digital current counts
(0100 0000 0000 0000).
Full scale total inductor current is
Ics
R
T
1
=DCR
T
(
I
CS
L
VO
GND
V
VCS
1
REF
+
current corresponds to
2
IR3720
, and R
I
L
I
2
VDD
CS
)
FS
I
=
2
3.3V
C Bus
=
I
(
CSFS
CS1
I
V
R
L
R
1
IG
T
=R
CS
+
=
⋅
1
I
To system
Controller
CS3
(
L
+
R
2
V
R
2
2
IG
CS
)
, then I
T
R
⋅
1
DCR
CS
DCR
+
2
2
1
⋅
CS
R
LOAD
CS
can be
2
)
09/09/08