
that swings above VREF voltage for positive-sense volt-
ages and below VREF for negative-sense voltages.
VOUT is equal to VREF when VSENSE is equal to zero.
Set the full-scale output range by selecting RSENSE and
the appropriate gain version of the MAX4080/
MAX4081.
76V, High-Side, Current-Sense Amplifiers with
Voltage Output
MAX4081T
VSENSE
ICHARGE
ILOAD
RSENSE
VCC
GND
RS+
RS-
OUT
REF1A
REF1B
5V
SYSTEM LOAD
AND CHARGER
BATTERY
VOUT = VGND
VOUT = 10V
VREF1A = VREF1B = 5V
DISCHARGE CURRENT
4.5V TO 76V
V
OUT
-
V
REF
CHARGE CURRENT
5V
10V
-250mV
250mV
-5V
VSENSE
Figure 1. MAX4081T OUT Transfer Curve
RSENSE
VSENSE
ILOAD
OUT
RG1
RG2
RS-
Q1
RS+
CURRENT
MIRROR
A1
IA2
A3
A2
MAX4080
VSENSE
RG1
RG2
VREF
RS-
REF1B
OUT
GND
REF1A
Q1
Q2
RF
125k
125k
RS+
CURRENT
MIRROR
CURRENT
MIRROR
A1
A2
MAX4081
Figure 3. MAX4081 Functional Diagram
Figure 2. MAX4080 Functional Diagram
Note: For Gain = 5 (F), RG1 = RG2 = 160k.
For Gain = 20 (T), RG1 = RG2 = 60k.
For Gain = 60 (S), RG1 = RG2 = 20k.
MAX4080/MAX4081
10
Maxim Integrated