IR2177SPBF International Rectifier, IR2177SPBF Datasheet - Page 14

• Manufacturer Part Number: IR2177SPBF
• Description: IC CURRENT SENSE 0.2% 16SOIC
• Manufacturer: International Rectifier

Specifications of IR2177SPBF

• Function: Current Sense
• Accuracy: ±0.2%
• Voltage - Input: 8 ~ 20 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (0.300", 7.5mm Width)
• Family Hvic: General Purpose HVICs
• Channels: 1
• Topology: Current Sense
• Application: General Purpose / Motor Control
• Voffset: 600
• Over Current Protection: Yes
• Package: 16 Lead
• Part Status: Active & Preferred
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Sensing Method: -

1.5 DC transfer functions
The working principle of the device can be easily
explained by Figure 13, in which the main signals
are represented.
PWM out (PO pin) gives a duty cycle which is
inversely proportional to the input signal while the
OUT pin gives the analog converted output.
Eq. 2 gives the resulting D
pin):
Eq. 2
where V
The Voltage-to-Time conversion (V
reconstructed (see Functional Block Diagram) to
give an analog voltage output at OUT pin.
OUT pin swings from V
output (referred to V
14
Triangular
reference
SYNC
Figure 13: Main current sensor signals and
VRH
OUT
VRL
Vin
PO
D
n
in
Figure 14: PO Duty Cycle (D
=
= V
20
PO duty cycle
inp
%
-V
−
inm
40
SS
outputs
) follows Eq. 3:
%
V
⋅
RL
V
30%
25%
20%
15%
10%
n
in
of the PWM output (PO
to V
RH
in
, so the analog
to PO) must be
n
)
V
in
Eq. 3
The same equation can be referred to V
follows in Eq. 4:
Eq. 4
OUT
Figure 15: ideal OUT/V
OUT
−
V
RL
=
=
2
2
⋅
⋅
(
(
V
V
IR2277S/IR2177S(PbF)
RH
OUT
RH
−
−
V
V
RL
RL
V
V
(V
in
RL
RH
)
)
RH
transfer function
⋅
⋅
V
V
+V
in
in
RL
+
+
)/2
V
V
RH
RH
www.irf.com
RL
2
+
2
−
, as
V
V
V
in
RL
RL