Questions tagged [current-sensing]

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2
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1answer
58 views

Measuring AC Current at High Voltages (up to 600VAC)

I've been looking at various ways to measure current for a while now, and am stumped on how to read high-side AC Current Measurements ohmically (no Hall Effect sensors). My initial thought was to use ...
0
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1answer
56 views

op-amp level shifter

I'm working on a brushed dc motor driver and I have to monitor the current. so I use ACHS-7121 current sensor. This sensor convert +-10A into 0V to +5V and have +2.5V in zero current. Now I want to ...
1
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1answer
63 views

Current Sensing with Op-Amp, do I need a shunt resistor in series with the load on the output?

Hi I am building a circuit to measure current draw from a load, I opted for a voltage follower with a transistor and a shunt in between, The transistor is needed to allow higher currents to flow ...
0
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1answer
50 views

Current sensing relay with delay on break for dust collection system

I am in the process of planning our a new workshop in a single car garage. I have a large 20A Dust Collector that needs to be on its own circuit or else it will trip. I also have a ceiling mounted ...
2
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3answers
166 views

Detecting switch closure

Any techniques/circuits/sensors that can determine the open/closed state of a set of contacts, independently of whatever power or signals are being switched by the contacts? Obviously easy if there's ...
0
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1answer
36 views

Output current and voltage levels regulation in ac/dc adapter

On the picture below is the output circuit of AC/DC adapter. I understand how voltage level contol works, but I don't understand how exactly current limitation works and how should I calculate ...
1
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1answer
56 views

High voltage and cheap differential amplifier

Can I use a LM324N (very common) op-amp to act as a high-side differential current sense op amp at high voltage? The Differential Amplifier The differential input voltage rating is 32v, but my load ...
0
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0answers
70 views

Problem writing to EEPROM in Allegro ACS71020 through SPI

I can't write all the EEPROM registries in the ACS71020. Before every writing I write the unlock code to 0x2F. Only the first writing takes place (register 0x0B), the others do not. In the datasheet ...
0
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1answer
28 views

Current monitor output doesn't respond to load changes

When I physically build this circuit the output voltage doesn't response to load variation. The voltage across the sense resistor is definitely increasing when decrease the load resistance, the ...
0
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1answer
58 views

Measuring high currents with toroids

I got a PT27312 current sensor (datasheet), I wonder if I can use it to measure currents up to 100A AC/DC. I couldn't find any specifications in respect of the current measurement range. I only know ...
0
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0answers
34 views

current remote sensing behind barriers

I'm trying to determine where a fault in a wire is located. The wire(s) are typically behind panels or other barrier which I want to avoid opening. I am considering detecting temperature changes (...
0
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1answer
27 views

Working Voltage for Basic/Reinforced Isolation (ACS712)

I'm planing to use current sense chip ACS712. I don't understand some values in its datasheet, page 2 (Isolation Characteristics). I understand "Dielectric Strength Test Voltage - 2100VAC" - that ...
0
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2answers
72 views

“ground disturbance” in current sensing with shunt resistor

There are lots of questions about "traditional" low-side current sensing using a shunt resistor. Most discussions and papers mention the drawback of "ground disturbance" introduced by the measurement ...
1
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1answer
34 views

XADC Current Sensing Reference Design

Please refer to this reference design for AC701 (snippet below). The schematics, specifically the current sensing sections in pages 34-36, show this: I want to understand why, for the REF output of ...
0
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2answers
56 views

How to connect multiple sensors to single PLC input?

Hello. I have a scenario where I have multiple PNP "error signal" from several sensors (let's assume 3 for now). If the sensor output is HIGH, then there is error. If the sensor output is LOW, then ...
6
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8answers
4k views

What is negative current?

I understand that voltage is relative to ground, so that can be negative. However, I'm currently looking at current-sensors (ACS712 current sensor) and in the performance characteristics table, it ...
0
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1answer
43 views

Current transducer - understanding of turns ratio connection

I'm using a LEM LAH 25-NP current sensor and I don't understand the recommended PCB connections in the table from the datasheet. I understand the first one, but what is with the second and third? What ...
0
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1answer
31 views

Current sensing using XADC

AC701 Schematics Refer page 40 of the schematics. Here for Vccint- the regulator is switching at 250 kHz. page 34 has the sensing signal conditioning for that the inst. amp used is INA333 which ...
2
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2answers
80 views

Current Sensing Amplifier Circuit explained

I've been trying to understand why each every comment is in the circuit shown. I understand that the amp is taking the voltage drop across the Rsense and amplifying it such that the current across it ...
0
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3answers
117 views

INA168 vs INA169 High-side current sensing

I have read the datasheets of the INA168 and the INA169 and can't see any difference, other than internal resistors value and quiscent current (25uA for INA168, 60uA for INA169). Those two were even ...
0
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2answers
48 views

Sensing Voltage and Current of an Adjustable Voltage Source

I am currently working on an Adjustable Voltage Source, the Voltage Source is built by a voltage regulator with an OpAmp with and a Darlington transistor for current amplifying as the following ...
0
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0answers
50 views

Current sense trace vias underneath shunt resistor

I need to connect current sense traces from a shunt resistor to my PMIC on the other side of the board. Due to space constraints, I'd like the traces to pass through vias directly underneath the shunt ...
0
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3answers
276 views

2000A current sensing using STM32

Is there any chance to read 2000A using STM32? I searched the Internet for low-value shunt resistor but nothing found. maybe some kind of current transformer could do the job!! any help will be ...
1
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0answers
32 views

Buck converter design using MCP1630V

I have already designed a buck converter with the following specifications using an MCP19035: Vin=14V, Vout=1.8V, Fc=63kHz(Crossover frequency), Vref=0.6V, Iout=10A step load High IOH=7.5A step ...
1
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0answers
32 views

Using a switching DC-DC converter in high dynamic range current/voltage sensing

I'm thinking of making a power meter circuit which will have a high-side current-sensing amp (LTC6102), a resistive voltage divider for sensing the voltage, a dual op-amp (OPA2365) as a buffer for the ...
0
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0answers
55 views

H-Bridge Low Side Sense Resistor - Position of Resistor and Bulk Capacitance

My question regards the considerations required in determining the location of a current sense resistor on the low-side of an H-Bridge. I've presented two scenarios. Details: The H-Bridge load is a ...
1
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1answer
2k views

ESP32 using acs712 give wrong values

I'm trying to measure current with acs712 30A current sensor connecting to NodeMCU-32S but I'm getting wrong and unstable values. For zero current the ADC pin should read value of 2048 (esp has 12 bit ...
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1answer
73 views

0-20mA to voltage conversion. Is this circuit OK?

Is this circuit OK, in your opinion?
0
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1answer
243 views

FOC sensor vs sensorless

I am trying to understand the hardware difference between the sensored and sensorless FOC 3-phase Induction Motor Drive circuit. So far what I understand is that FOC require following sensors: 1. ...
0
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1answer
123 views

SMPS Current Sense Resistor Selection

I am looking into using an SPV1040 boost converter to charge a battery from a solar cell. The chip includes inputs for a current sense resistor, which are described in one of ST's applications notes ...
2
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1answer
376 views

Shunt resistors and PCB layout

I have several questions about the current sensing through a resistance. The resistances are 2-SMD package and I will use the 4-wire kelvin method for the layout.(see image) Specifically, there are ...
-1
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1answer
141 views

Current sensing for side channel analysis

I'm trying to design a power supply with a built in current sensor for a digital system. The purpose is for side channel analysis. In current sensing, I would like to detect both the AC and DC current....
1
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2answers
63 views

Over-current sense

I am using a circuit shown below. it is designed to sense 1.5 A whenever the load takes current >= 1.5 A. Rsen senses the related voltage and activates the transistor. Here I use a Rsen = 0.46 R(0.7V/...
1
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2answers
169 views

Four-terminal resistor pinout?

Anyone can tell me (or preferably, point me to a source that explicitly shows) the pinout of the 4-pin current-sense resistors? I'm seeing the datasheets for three different models (including Rideon'...
0
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3answers
162 views

Current sensing on negative 1.1kV DC rail

I searching for a way to do high side current sensing on a -1100V DC rail. My HV is generated from the hamamatsu C9619 High voltage power supply module and it powers the hamamatsu R647P ...
3
votes
2answers
133 views

High side current sensing for negative high voltage

I need to monitor the current for a negative high voltage supply. I implemented the following circuit in a simulation program: https://www.maximintegrated.com/en/app-notes/index.mvp/id/1867 But ...
0
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2answers
229 views

Overcurrent Sensing

I am designing an overcurrent protection circuit. I am sensing current with a LEM sensor across a sensing resistor of 16.5 ohm. The voltage drop for maximum current is 2 V. In the next stage I am ...
2
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0answers
154 views

High voltage 1100 V current sense on the high side

I have the circuit that you see below. My load is a photomultiplier tube equivalent to a 3.63Mohm resistor. My power supply can deliver max 4W (2kV and 2mA). I use it on 1100V and the load draws ~...
3
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1answer
589 views

Noise problems in current sensing

I have the following circuit: simulate this circuit – Schematic created using CircuitLab I am using a motor from an electric bike, as a generator and I am rotating it using a drill, to test ...
0
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1answer
398 views

Low side current sensing

I’m making a BLDC motor controller application. The motor control IC (Allegro A4931) uses low side current sensing (R7,R8,R9) for controlling the motor. Unfortunately the motor IC does not output a ...
1
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2answers
211 views

Placement of sense resistor on DC-DC converter

For my design I am using DC-DC converters LTM4620 and LTM4644, which integrate the MOSFETs and the inductor in the chip. For measuring the output current, I will add a sense resistor in each output ...
2
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0answers
55 views

Problem simulating LMP8645 current sense amplfiier in LTspice

Basically the problem i am getting is that the output offset voltage is extremely large (58mv) here is the datasheet for the amp: http://www.ti.com/lit/ds/symlink/lmp8645hv.pdf on page 9 it shows ...
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1answer
1k views

How to measure DC current with a microcontroller?

I have a project where I need to measure DC currents in the range of 0-150 A. I am using an STM32F446RE MCU. I can't use the solution where I convert current to voltage using resistors and reading ...
0
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1answer
288 views

high side vs low side current sensing in isolated bench power supplies, does it matter?

I'm trying to make a couple of mains isolated, transformer based, bench power supplies. Considering that the current sense resistor will be in the PSU box and external loads will not have access to ...
0
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0answers
145 views

High side current sensing in BLDC motor?

I want to measure DC current flow through the 48 V battery in bldc motor (through Inverter circuit). Are INA 282, INA 169 work properly or not? Since my battery motor specification is 48 V, 5 Amp, 250 ...
0
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2answers
125 views

Real Time AC Current Sensing [closed]

I'm trying to analyse the harmonics present in different household devices's current waveforms. For this, I need a CT based current sensor which can sample data quite accurately and quickly (around 5% ...
1
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1answer
126 views

Current sense amplifier working principle

i am running a bldc motor Infineon TLE9879 chip. Now i want to measure the current flowing through the motor. so i use the current sense amplifier where the motor current is converted to a voltage by ...
0
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2answers
46 views

Sensing Mobile Battery full and cutting down power on V_bus line

I just come across the situation to cutoff the power when mobile battery full is detected (by breaking the +5v line) .I planned to implement this using high side current sensing method.When the ...
0
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1answer
466 views

Closed loop control of PWM using current sensing method

This is the block diagram of the project i am working on. I have a DC voltage range of input as 8V to 16V. The duty cycle at the PWM generation should change automatically from 10% to 90%. I require ...
1
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2answers
470 views

High-side current sensing with a rail-bound instrumentation amplifier?

I know that current shunt monitor ICs and high common-mode voltage differential amplifiers like the INA117 and AD629 exist but I'd like to know if it's possible to use a regular instrumentation ...