Questions tagged [current-sensing]
The current-sensing tag has no usage guidance.
180 questions
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Can a 4 to 20 mA current loop be measured without using a resistor?
Background
There is an electrical system typically consisting of a 4 to 20 mA transmitter and receiver.
simulate this circuit – Schematic created using CircuitLab
So far, everything is working ...
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0
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ACS71020-I2C data read problem
I recently working on ACS71020 with I2C communication .I will attach my module details, code and my results. The slave address of the I2C keeps changing and even If I turn on the supply the measured ...
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3
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Sensing current down to tens of nA with INA828 or other OPA
I need to measure the current draw of DUT that can be an MCU in deep sleep, such as Attiny85, or a more power hungry MCU that is powered off by TPL5110. In this post, I proposed a circuit where an ...
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2
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INA828 for sensing current down to tens of nA
I need to measure the voltage drop across a test resistor in order to sense the current flowing through it. This test resistor has a value of 1 MOhm and it's connected between the positive voltage of ...
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Window current detection through a current sense differential amplifier and a comparator
I'd like to implement a circuit to detect the over-current through a grounded load. The limits for that current are either 3mA DC current or -3mA and 3mA in case of bipolar AC current. I want to ...
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1
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Makerbase TMC2226 stepper driver board: are current sense resistors underrated power-dissipation-wise?
I am looking at the schematics for Makerbase TMC2226 stepper driver board:
The schematic shows 1/8W 0.11 ohm current sense resistors.
The datasheet for TMC2226 IC says:
8 Selecting Sense Resistors
.....
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2
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1
answer
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Can I use the existing current-sense resistor of LTC1473 for my own measurement?
I'm making a powerpath battery switcher using LTC1473. For its own inrush/short management, the LTC1473 uses a shunt resistor connected to its sense+ and sense- pins.
Since I also need the current ...
- 2,163
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How to sample current in high-kHz to low-MHz [closed]
I am working on a project that, at its simplest, is a switching circuit (either a half-bridge or single switch) connected to a resonant filter. I need a way to measure/sample the current going from ...
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Current sensing in DC-DC converter
I studied DC-DC converter in peak/valley/average mode control and I have a question about the methodology to sense the current in average current mode control. I saw lot of paper about DCR sensing but ...
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Troubleshooting Voltage Sensing Issues in Buck-Boost Chip Simulations
I performed a simulation on a buck-boost chip (LT8390). I understand that the sensing resistor placed between LSP and LSN is supposed to sense the differential voltage. This voltage is then amplified ...
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Sensing Resistor in Buck-Boost controllers
In the LT8390, there are two sensing resistors. The one connected to LSN/LSP is called RSENSE(Buck), and the one connected to ISP/ISN is called RSENSE(BOOST). To illustrate this more clearly, I've ...
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Allegro current sensors on 220 VAC mains
A friend is designing a power meter for 220 VAC mains and is considering Allegro current sensors like the ACS37002 or ACS71240. Those sensors put a wire with a sub-ohm resistance in line with the ...
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Unipolar stepper driven PWM to reduce voltage
I need to drop voltage for unipolar stepper motor with winding resistance 50ohm and inductance 40mH (measured with generator and oscilloscope for equivalent circuit Rout + (Rl + L)). Available Vcc is ...
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High-side driver current monitoring via microcontroller
I'm building an automotive power distribution module which makes use of the Infineon BTS50010 high-side driver.
The high-side driver current is monitored via the sense pin (IS) connected to a ...
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Current-sense resistor switching mechanism
I planned to make a DIY power meter with automatic switch for current range, usually towards low (uA maybe) currents.
I came up with the design below to switch between various current-sense resistors. ...
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Choosing an adequate op-amp for shunt resistor sensing in SMPS applications
I would like to get some industry experts / design engineers opinion about potential methods to improve the proposed shunt resistor current sensing method below. The intention is to improve this ...
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Understanding current sense circuit
I'm trying to adapt a current limiter design that I found, and I'm having trouble understanding the "current sense" part of it.
The current sensing is implemented using a shunt resistor, ...
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4
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525
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High-side current sensing using PNP
I have the following three states:
State 1: When system is active with transducers, current through the load is approximately 350 mA.
State 2: When system is activated without transducers, current ...
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2
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1
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172
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How to sense a varying current and voltage without affecting the load
I've been asked to build a circuit to switch a constant power (varying current & voltage) supply between two loads, for a research experiment the customer is carrying out. The loads are unknown ...
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2
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360
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Designing a current sensing op-amp circuit for an AC load
I'm trying to simulate a current sensing op-amp circuit. My AC voltage, 24 VAC, is across a load of 10 Ω. I used a 100 μΩ resistor and measured the voltage across it using an op-amp.
Looking at some ...
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2
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147
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Flyback converter sense resistor placement and wiring
I am designing my first ever Flyback converter. The Fsw = 100kHz. Peak primary current = 3.26A.
The converter has to fit in a very small space, so I'm making a lot of compromises. For example, I could ...
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2
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76
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Issue with influence between channels in a dual-channel high-side current sensing circuit
I've designed a two-channel current sensing circuit integrated into a board that outputs two separate signals. However, I'm encountering an issue where one channel seems to influence the other, which, ...
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Is there a reliable way to sense RPM without modifying a spark plug cable?
I need to recreate a tachometer without altering the wire that goes to the engine spark plug. I can only modify the wiring intended to close the circuit to turn off the engine. It is necessary to take ...
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Is it wise to determine heating element temperature from resistivity?
Context
I'm making an electric furnace for melting metal, and aiming to make my own controller.
Everyone seems to just use thermocouples and a control loop, I thought perhaps I could just measure the ...
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9
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Is it feasible to measure voltage drop across 0-ohm jumper resistors to determine excessive current draw?
We design very low-power devices which in standby mode use about 8 µA of current. They are powered by 3 V lithium primary cells and are designed to last for many years.
Every now and then we see a ...
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Need to understand the current sensor connection in this circuit
I'm working on creating a smart power meter for my home, and I found this tutorial. I want to understand each part of the circuit, and the tutorial covers everything. However, it doesn't explain why ...
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164
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Input Filter for Current Sense Amplifier - ODrive
Out of curiosity, can anyone explain to me why the input filters for the current sense amplifiers in the old ODrive schematics are unbalanced (i.e., the external resistor is only on the negative CSA ...
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3
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395
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Designing Eddy Current Sensor?
I am looking to build a eddy current sensor, I am having difficulty finding information on how I should be designing the sensor to fit my needs. There's a few studies and articles I've found that ...
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How do I make the circuit to sense the collector current for the FAN1100-F085?
I am trying to design an ignition coil driver using the FAN1100-F085 IC and a ISL9V3040x3ST−F085C IGBT.
I am having trouble understanding the datasheet when it comes to the current sensing. It says to ...
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How is this a current mirror?
This article is talking about floating an IC's GND to use it at a common mode voltage higher than it is rated for. It then says it level shifts the IC's current output to ground by using the Q1-Q2 ...
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1
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540
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Current Transformer Current Sensing via operational-amplifier
This is a current sensing circuit, L1(CT2320) is a current transformer, U1 is generated by IGBT inverter ，U is one of a three phase of the motor driver voltage. I have several questions about this ...
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SCR falsely triggered on startup (battery low current monitor)
I'm trying to build a li ion low charge current detector and cutoff circuit as a complement to my battery charging setup. Charging should be disconnected when the current reaches 400mA or below. I'...
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Current measurement with LT6015, simulation doesn't work
I'm trying to simulate high side shunt resistor current measurement using LT6015 op amp, but the simulation doesn't work I'm always having the same output even if I change the current. Can somebody ...
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LTspice simulation of a fluxgate excitation circuit with H bridge driver, Op-Amp and comparator not behaving as expected
Please see the following LTspice schematic:
This is an excitation circuit for a fluxgate current sensor. The inductor L1 models the magnetic core's B-H loop and dimension along with a sensing winding ...
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2
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Is amplification needed for high-side current sensing?
I have a 5 V system and I want to monitor the current in different parts of the system. I am planning to place a small value resistor on the positive power rail and feed the rail voltage and the ...
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Current detector transformer on optocoupler
I need a current detector that outputs a logic signal (1 or 0). I DON'T need to measure current.
Detected current: AC.
Voltage: 220V.
Load power: ~1kW.
FOR EXAMPLE: I need a current detector that ...
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How to sense if a heater is plugged and on
I want to remotely check if one of my home sockets (which happens to power a heater) is transmitting current or not. I do this as a hobby project, so my main priority is to learn through the process ...
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Removing the effects of Parasitic Inductance in current sense resistor – Low side current sensing
We are evaluating MIC21LV32 from microchip in one of our applications.
For the current sensing we have used 3 mΩ sense resistor (1206, 1 %, 1 W), as these sense resistors have higher ESL+ parasitic ...
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2
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1
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265
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LEM current transducer 2.5 V internal reference
I am testing a LEM LTSR-25-NP current transducer. According to the datasheet, the current transducer should be outputting 2.5 V +/- 0.025 V when the input current is 0 A, but this is not what I am ...
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AC Current Sensing LED indicator circuit
I'm playing around with a circuit to drive a LED based on the output from a current sensing transformer. The idea is to have the LED appear proportionally brighter with the output from the current ...
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3
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How can we say this current sensor doesn't measure DC?
Digikey is saying this current sensor "CS0305B" from CUI Devices can measure AC and not DC.
But in datasheet there is no reference or note mentioning this current sensor will not measure DC.
...
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Best approach for using multiple power monitors with single MCU (SPI)
I'm working on a project where I'm using several buck converters controlled by the same MCU (ESP32) and I will be adding a digital Power monitor to each converter. but I'm concerned about the number ...
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Current sensing resistor placement [closed]
I will be adding a current sensing resistor to a Buck-boost DC-DC converter. Based on the IC datasheet, the resistor is placed at the low-voltage side next to the power inductor.
But, as far as I know,...
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2
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Inrush current on current sense resistors
The problem is on a circuit which implements PFC circuitry.
There are two parallel 0.36R current sense resistors located in the inrush current path. These resistors measure the PFC current through the ...
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Current Sensing Trace Routing
I'm developing a motor control board (sensorless FOC). I have a question about the differential pair traces, they are very long (the longest is about 80 mm) and crosses several gate lines. How bad is ...
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1
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Current sensor for sensing 6 mA DC & 30 mA AC current [closed]
I want to sense very low currents for both AC & DC for an EV charger application. General AC & DC sensors do not have that much range to sense the current. Please suggest some good component ...
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2
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567
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What does sensitivity mean for a current sensor when given in "mV/N" or "mV/mT" rather than "mV/A"?
I have been analyzing various datasheets of current sensors and majorly getting sensitivity given in "mV/A," from which I understand the output voltage per 1 ampere. I do not understand it ...
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Self powered current sense in tapped inductor buck converter
I am interested in designing the autonomous (both turn on and off) high-side high-voltage switch proposed in this paper. The proposed topology of the high-side switch is as follow:
Auto-turning on is ...
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How to sense the current an amplifier is supplying?
Consider the circuit below. It is made up of three parts: input, bidirectional amplifier, and output. If we set the gain of the amplifier to 1, then it as if we've just connected the input to the ...
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Choosing the kind of current sensing method and the voltage of the testing signal for a DIY LCR meter
I have been designing my own LCR meter that uses the V-I method to make measurements. I have finished the sine wave generator and processor side, but I got stuck at the sensing part.
Here I have 3 ...
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