Texas Instruments Evaluation Board for LMP8640 LMP8640HV-FEVAL/NOPB LMP8640HV-FEVAL/NOPB 데이터 시트
제품 코드
LMP8640HV-FEVAL/NOPB
x
Vref =
Amp
_
VCC
5
R
6
R
5
R +
OUT = -
¹
·
©
§
R1
R4
* OUT
-
+
R1
R4
1 +
¹
·
©
§
R2 + R3
R2
* Vref +
R2 + R3
R3
* OUT
+
Hardware Setup
3.2
Source and Load Setup
First case: Current flows from IN to LOAD plugs.
A voltage supply can be connected between the IN and the GND banana plugs, while a load is connected
between the LOAD and the GND banana plugs. The voltage applied at the IN pin should not exceed the
maximum common mode voltage allowed by the LMP8640/HV (LMP8645/HV). The maximum allowed
common mode voltages are listed in
between the LOAD and the GND banana plugs. The voltage applied at the IN pin should not exceed the
maximum common mode voltage allowed by the LMP8640/HV (LMP8645/HV). The maximum allowed
common mode voltages are listed in
.
Second case: Current flows from LOAD to IN plugs.
In this case, the voltage supply is connected between the LOAD and the GND banana plugs, while the
load is connected between the IN and GND banana plugs. The voltage applied at LOAD pin should not
exceed the maximum common mode voltage allowed by the LMP8640/HV (LMP8645/HV). The maximum
allowed common mode voltages are listed in
load is connected between the IN and GND banana plugs. The voltage applied at LOAD pin should not
exceed the maximum common mode voltage allowed by the LMP8640/HV (LMP8645/HV). The maximum
allowed common mode voltages are listed in
Table 3. Max Common Mode Voltage
DEVICE
MAX VCM
LMP8640
42V
LMP8645
42V
LMP8640HV
76V
LMP8645HV
76V
According to the shunt resistor (Rsns), to the gain of LMP8640 (LMP8645) and to the supply voltage
different ranges of currents can be sensed with this evaluation board.
different ranges of currents can be sensed with this evaluation board.
3.3
Components
On the evaluation board, there are already the circuit and the footprint of a standard dual op amp (U3) to
implement a differential op amp (U3.B) with reference (U3.A) in order to provide a single ended output of
the bidirectional current.
implement a differential op amp (U3.B) with reference (U3.A) in order to provide a single ended output of
the bidirectional current.
Table 4. Optional Differential Circuit
U3
Standard Dual Op Amp 8 pin.
U3.1
U3.1
OUT A
U3.2
-IN A
U3.3
+IN A
U3.4
V
-
U3.5
+IN B
U3.6
-IN B
U3.7
OUT B
U3.8
V
+
R1, R2, R3, R4 resistors that implement the differential circuit according to
(1)
R5, R6, C5
components for voltage reference and its filter. The voltage reference is calculating according to
:
(2)
2
AN-1975 LMP8640/LMP8645 Evaluation Board
SNOA546C – November 2009 – Revised April 2013
Copyright © 2009–2013, Texas Instruments Incorporated