符合英文
Current Shunt Monitors
Power
Supply
• Current shunt monitors are also referred to as current n amplifiers.• Current shunt monitors are designed to monitor the current flow by measuring the voltage drop across a resistor placed in the current path.• Current n amplifiers tend to be easier to design, more preci, less prone to noi and lower cost than magnetic current nsors.
Common Mode Range:
This specification defines the DC voltage range at the input of an amplifier with respect to ground. Current shunt monitors are typically designed to accept common mode voltages well beyond the chip supply voltage. For example, the INA282
is capable of accepting a common mode voltage from -14V to +80V while running on a supply as low
as 2.7V. Offt Voltage:
The differential DC error at the input
of the amplifier. Historically, to reduce
the impact of amplifiers with high
offts, larger shunt resistors are ud
to increa the measured voltage
drop. Today, TI is able to offer current
nsing solutions with offts as low
as 10µV, enabling higher precision
measurements at low currents and the
u of smaller shunt resistances for
improved system efficiency.
CMRR
(Common Mode Rejection Ratio):
CMRR is the ability of the amplifier
to reject signals common to the
differential inputs. This is important
in the ability to measure small signals
superimpod upon a large voltage.
TI’s portfolio offers solutions with
CMRR as high as 140dB.
Digital Output:Simple all-in-one solution integrating the ADC/MUX with programmable switching. Pro澳门理工学院分数线
vides measurements in amps, volts and watts across the I2C interface for a complete power monitoring solution.
heavytraffic
REF
lgbt法案是什么意思
OUT
V
V
Voltage Output: High precision, lowest power and
industry’s smallest form factors. Fixed gain options
ranging from 14V/V to 1000V/V. Variable gain may be
t through an external resistor.
Current Output: Variable gain t through
external resistor. Highest bandwidth options.
V
OUT
V
V
Output Types
Key Parameters
What are Current Shunt Monitors?
C
Power Advantages:
• Typically only requires an op amp such as OPA335
Straightforward, easy Inexpensive Disadvantages:
• Undesirable resistance in the load’s ground path
• Cannot detect fault conditions (short/open circuits)
• Requires precision external components to achieve and maintain high accuracy
Advantages over op amps as a low-side monitor :
• Integrated gain resistors
Excellent matching that requires more expensive external precision resistors with an op amp approach Integrated resistors approach
reduces board space requirements Disadvantages over op amps:
• Fixed gain ttings reduce flexibility in maximizing the full-scale range of the following ADC stage
Low-side current nsing techniques connect the current n element between the load and ground.
When to choo low-side nsing: Always choo low-side nsing if the system can tolerate distur
bances on the ground path.
High-side monitors are designed to accommodate input voltages that exceed the power supply voltage. However, many of our current shunt monitors have
common-mode ranges that include or even go below ground. This makes them excellent low-side current shunt monitors as well.
Advantages:
• Eliminates ground disturbances associated with low-side nsing • Able to detect fault conditions Disadvantages:
• Difficult to u standard op amp. Resistors must be precily matched to obtain acceptable common mode rejection ratios (CMRR)
A 0.01% deviation in resistor value lowers the CMRR to 86d
B approach
A 0.1% deviation in resistor value lowers the CMRR to 66dB
杂七杂八的英文
A 1% deviation in resistor value lowers the CMRR to 46dB
• Must withstand very high, dynamic changes in common mode voltage
High-side current nsing techniques connect the current n element between the supply and the load.
When to choo high-side nsing:
• System cannot tolerate ground disturbance of low side nsing • System needs to be able to identify shorts to ground
C
High-Side Measurements
Low-Side Measurements With a High-Side Monitor
Low-Side Measurements
2C
• For small differential signals at the input, the error is dominated by the amplifier’s offt voltage. Low input offts are critical to achieving accurate measurements at the low end of the dynamic range.
• For large differential signals at the input, the error is dominated by the
amplifier’s gain error.
0%
2%
rising star4%
6%
8%
10%0
10
20
30
40
50
60
70
80
90
100
T o t a l E r r o r %
Differential Voltage (mV)
10µV; 0.1%10µV; 1%detect
1mV; 1%1mV; 5%
Offt; Gain Error
Extending the Common Mode Range
Example 1: MOSFET and Zener
R
S
Supply +160 to +200V
Example 3: Isolated SPI Interface
Example 4: Isolated I 2C Interface
Example 2: Current Follower
With additional circuitry, current shunts can be configured to operate beyond the specified common mode range by using one of the following techniques.Total Error
Data (SCL)
Shunt
INA226:Highest precision solution on the market
• Integrated ADC and MUX with programmable sampling
• Common mode range = 0V to 36V • Offt (max) = 10µV
• Gain error (max) = 0.1%
• CMRR (typ) = 140dB
• Lower cost alternative: INA219, INA230
INA210: Precision voltage output • Gain options: 50V/V, 100V/V,
200V/V, 500V/V, 1000V/V
• Common mode range: –0.3V to 26V • Offt (max) = 35µV
• Gain error (max) = 1%
• CMRR (typ) = 140dB
• Lower cost alternative: INA199
INA216: Designed for portable battery powered applications
• Gain options: 25V/V, 50V/V, 100V/V, 200V/V
• Common mode range = 1.8V to 5.5V • Offt (max) = 75µV
• Gain error (max) = 0.2%
• Quiescent current = 25µA
• CMRR (typ) = 108dB
• 0.76 x 0.76mm WCSP or QFN package available
INA3221: Triple-channel digital shunt and bus voltage monitor
• Integrated ADC and MUX with programmable sampling
• Common mode range = 0V to 26V • Offt error (max) = 80µV
• Gain error (max): 0.5%
• Quiescent current = 450µA INA282:Widest common mode
range + precision
• Common mode range = -14V to 80V
remedy是什么意思• Offt (max) = 70µV
• Offt drift (max) = 1.5µV/ºC
• Gain error (max) = 1.4%
err
• CMRR (typ) = 140dB
• Lower cost alternative: INA193,
LMP8601
LMP8640:High bandwidth and
high voltage
• Bandwidth = 950kHz
• Common mode range: -2V to 76V
• Offt (max) = 900µV
• Gain error = 0.25%
• CMRR (min) = 103dB
• Lower cost alternative: LMP8645
AMC1200: 4kV isolated amplifier
• Offt (max) = 1.5mV
• Offt drift (max) = 10µV/K
• Gain error (max) = 1%
• CMRR (typ) = 108dB
LMP8481:High voltage
• Bandwidth = 270kHz
• Common mode range = 4.0V to 76V
• Offt (max) = 400µV
• Gain error (max) = 1.2%
together是什么意思
• CMRR (typ) = 124dB
• Lower cost alternative: LMP8480
LMP92064: Simultaneous sampling
current/voltage monitor
• 125ksamples/c
• Bandwidth = 70kHz
• Offt (max) = 60µV
• Gain error (max) = 0.75%
INA225:Programmable gain,
zero-drift current n amplifier
• 4-pin lectable gain ttings
• Bandwidth = 100kHz @ 100V/V
• Offt (max) = 125µV
• Gain error (max) = 0.50%
INA300:Over current detector
• Input/output respon time = 10µs
• Programmable threshold:
0 to 250mV
• Hysteresis of 2, 5, or 10mV
Featured Products
