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Cheap high current sensing solution

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seyyah

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I need to sense the currents between 0-20A and process them. I think high side current sensing has some advantages over low side sensing. And i think there are "ready to serve" ICs for this purpose which requires only a sensing resistor, or some other components or nothing. So what can you suggest me for this job which have the following porperties: easy implementation and wide availability, prefarably low cost and low extra components. If there are mature and good enough devices they are also welcome because i think buying and using them is easier because i think they can be found widely and there will be more applicaton notes etc.
 

hall effect sensor high current dc

8) For high side sensing u can use small hall sensors.
 

high side current sense 100a

AFAIK there are no integral sensors for such currents.
The measuring methods depends on AC or DC current,
the precision, etc.
If the current is DC then it generates some magnetic field
which can be measuerd by Hall chip.
But the precision is very small (several percents).
If the current is AC then usually the transformer is used which first wire consists of a single winding which is put into the cable with measured current.
But it is not a chip at all.
 

sensing high current

Look for ZETEX magnetic sensors: ZMC, ZMX, ZMY and ZMZ series.

**broken link removed**
 

current sensing using allegro hall sensor

Take a look at Allegro's sensors:

**broken link removed**
**broken link removed**

Samples are available :D

Excerpt from site:



Features and Benefits
Monolithic Hall IC for high reliability
Single +5 V supply
High isolation voltage
Lead-free
UL recognized
End-of-line factory-trimmed for gain and offset
Ultra-low power loss: low resistance of primary conductor
Ratiometric output from supply voltage
Low thermal drift of offset voltage
On-chip transient protection
Small package size, with easy mounting capability
Applications
Industrial systems
Motor control
Power distribution
Battery powered systems
Electric vehicles
Description
The Allegro ACS752 family of current sensors provides economical and precise solutions for current sensing in industrial, commercial, and communications systems. The device package allows easy implementation by the customer. Typical applications include: motor control, load detection and management, switched mode power supplies, and overcurrent fault protection.

The sensor consists of a precision linear Hall IC, which is optimized to an internal magnetic circuit to increase device sensitivity. The combination of a precisely controlled self-aligning assembly process (patents pending), and the factory programmed precision of the linear Hall sensor, result in high-level performance and product uniformity.

The primary conductor used for current sensing (terminals 4 and 5) is designed for extremely low power loss. These power terminals also are electrically isolated from the sensor leads (pins 1, 2, and 3). This allows the ACS752 family of sensors to be used in applications requiring electrical isolation, without using opto-isolators or other costly isolation techniques.

The output of this device has a positive slope (>VCC / 2) when an increasing current flows from terminal 4 to terminal 5.


Cheers,
FoxyRick.
 

high current sensing

If you sense such o current range i recommend:
make your sensor own using a small toroid,
first determine the ratio and signal levels and also frequency range of the current signal the use an op-amp to convert current signal into voltage
this actually works and there is no need to use very cost sensors!!!
 

Re: high current sensing

8) Ya,
I recieved 5 samples of integrated hall effect current sensors from allegro in a nice small plastic box.
 

Re: high current sensing

You can use LEM-converters (quite huge, expensive but have high current ratings).

As a monolythic version there is a chip from m@xim, look here:
h**p://para.maxim-ic.com:80/compare.asp?Fam=CS_Amp&Tree=PowerSupplies&HP=PowerSupplies.cfm&ln=


hope it helps,
aOxOmOx
 

Re: high current sensing

So much have been talked about high current sense. Is there anyway to sense a minimum of 10mA to a max 5A DC current ?

I have looked at those Hall Effect Current Sensors from Allegro and realised that they could only sense a minimum of 0.3% of their rated current.

For example, 100A rated Hall Effect sensor coul donly sense the smallest deviation of 0.3A which translate to 300mA.

Anybody got any sensor in that range (10mA ~ 5A DC) ?

Thanks

Cheers,
 

high current sensing

These people make GMR sensors, and claim they can be magnetically overloaded without damaging the sensor. So perhaps 2 of these, one large scale, one small scale.

**broken link removed**
 

Re: high current sensing

rauol said:
8) For high side sensing u can use small hall sensors.
Click to expand...
Read the datasheets of the Hall effect sensors carefully. Some of them have a nonzero minimum current below which it will not sense. E.g. the current range can be 5A to 20A.

I would second Maduran's recommendation to use magneto-resistive sensors made by Zetex.

- Nick
 

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