Questions tagged [current-sensing]

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6
votes
8answers
14k 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
votes
1answer
62 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
votes
1answer
49 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
votes
2answers
101 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
votes
3answers
281 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
votes
2answers
72 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
votes
0answers
104 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
votes
3answers
644 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
vote
0answers
47 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
vote
0answers
51 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
votes
0answers
129 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 ...
2
votes
1answer
6k 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 ...
-2
votes
1answer
75 views

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

Is this circuit OK, in your opinion?
0
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1answer
623 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
votes
1answer
232 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
votes
1answer
921 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
votes
1answer
178 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
vote
2answers
136 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
vote
2answers
400 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
votes
3answers
209 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
220 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
votes
2answers
332 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
votes
0answers
175 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 ~...
5
votes
1answer
902 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
votes
1answer
654 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
vote
2answers
327 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
votes
0answers
127 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 ...
-3
votes
1answer
2k 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
votes
1answer
472 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
votes
0answers
173 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
votes
2answers
135 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
vote
1answer
167 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
votes
2answers
50 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
votes
1answer
723 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
vote
2answers
655 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 ...
5
votes
1answer
278 views

Wide range current sensing at +5kVDC

I am working on a control and interface board for high voltage supplies, which requires some current measurement to be implemented. The general terms of the question are similar to this one. The ...
1
vote
1answer
197 views

Precision of estimating power consumption with a current sensor

When estimating power consumption with a current sensor, what is the usual precision that can be achieved for home appliances? I'd like to make a simple circuit using such a sensor and a ...
1
vote
2answers
4k views

AC Current Sensing Switch Using Current Transformer

I'm struggling to design a circuit that will interpret signals from a SCT013 current transformer and trigger a constant 5v signal (which will go to a microcontroller) when a certain current threshold ...
1
vote
2answers
338 views

Differential amplifier for current measurement

I'm studying reference design from TI (pdf).This design shows the solenoid control circuit. I was interested, why a differential amplifier is used to measure the current? Why not use non-inverting ...
1
vote
1answer
84 views

Current sensing application

The purpose of the application is to maintain a constant current at the load, even if the resistance changes. I understand that the ADC is reporting the voltage and current values at the load to the ...
0
votes
1answer
1k views

Turn vacuum on when another load (eg. drill/saw/etc.) is active [duplicate]

I need to turn ON (and OFF if possible) a vacuum when another DIY tool, like a drill, is activated/deactivated. The idea is: "I start working and the vacuum start sucking dust automatically. Then it ...
2
votes
3answers
1k views

High-side current sensing diagram

I have a load that can be connected or disconnected from a +5V source (let's assume there is a switch). My target is to trigger an output to high-level voltage if the load is connected, and trigger it ...
1
vote
1answer
529 views

High side, high voltage, micro ampere current sensing

I am working on a project in which I am required to sense current in micro ampere range from a 2kV power supply. Here is a link of an article which I am referring. https://www.maximintegrated.com/en/...
1
vote
1answer
285 views

What are shunts, as related to their use in current sensing in microcontrollers?

Within the manual for the I/O module I'm using (a Loytec LIOB-153) there are wiring diagrams to aid in wiring up your sensors and other inputs/outputs. There are two wiring diagrams for the purpose of ...
1
vote
3answers
1k views

Spikes - DC Motor Current Sensing

I'm using a drv8838 to run a small dc motor (<1A). For current sensing I set up a INA199 (see layout). I'm also using a RC lowpass with a cut off frequency of around 70Hz to filter the shunt ...
1
vote
1answer
131 views

Common mode error formula from TI seems counter intuitive

I'm working on an application to measure current in a buck converter using a current sense amplifier. According to this video from Texas instriment, the equation for common mode error is same as eqn 1 ...
0
votes
1answer
190 views

closed loop hall effect sensor operation

I know that closed loop hall effect sensors generate a current in the secondary winding to oppose the flux in the core such that the net flux will equal zero. At this point the current in the primary ...
1
vote
2answers
793 views

Current sensing with Rdson?

I'm fooling around with a PMOS, a Fairchild FDD6637, and pondering whether it would be possible to use Rdson as a sort of shunt-resistance for measuring the voltage drop, to get the amount of current ...
0
votes
1answer
180 views

Inexpensive field deployable non-invasive current sensor [closed]

Is there an inexpensive way to MacGyver a non-invasive current sensor together in a field (yes, a literal field), assuming some prior planning? The context here is an event similar to EMF Camp or OHM,...
1
vote
3answers
473 views

AC current sensing using micro-controller and suitable circuit

I'm working on the project in which I need to measure AC current. The main problem I am facing is small current amplitude. I have to obtain the current waveform(I need complete waveform not just RMS ...