If you want to measure the current of your gpu

May 11, 2008
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With all the current measuring lately and you want to keep track of your (mining ?) system, you might want to do some modding of your own.
With your embedded mcu or arduino combined with an accurate (at least 14 bit) adc, you can create your own logging or power guarding system.

If you want to measure the current of your gpu 12V yourself, and you like to mod. Allegro has calibrated hall effect current sensors.

ACS714: Automotive Grade, Fully Integrated, Hall Effect-Based Linear Current Sensor IC with 2.1 kVRMS Voltage Isolation and a Low-Resistance Current Conductor

The Allegro ACS714 provides economical and precise solutions for AC or DC current sensing in automotive systems. The device package allows for easy implementation by the customer. Typical applications include motor control, load detection and management, switched-mode power supplies, and overcurrent fault protection.

The device consists of a precise, low-offset, linear Hall sensor circuit with a copper conduction path located near the surface of the die. Applied current flowing through this copper conduction path generates a magnetic field which is sensed by the integrated Hall IC and converted into a proportional voltage. Device accuracy is optimized through the close proximity of the magnetic signal to the Hall transducer. A precise, proportional voltage is provided by the low-offset, chopper-stabilized BiCMOS Hall IC, which is programmed for accuracy after packaging.

The output of the device has a positive slope (>VIOUT(Q)) when an increasing current flows through the primary copper conduction path (from pins 1 and 2, to pins 3 and 4), which is the path used for current sensing. The internal resistance of this conductive path is 1.2 mΩ typical, providing low power loss. The thickness of the copper conductor allows survival of the device at up to 5× overcurrent conditions. The terminals of the conductive path are electrically isolated from the sensor leads (pins 5 through 8). This allows the ACS714 current sensor IC to be used in applications requiring electrical isolation without the use of opto-isolators or other costly isolation techniques.

The ACS714 is provided in a small, surface mount SOIC8 package. The leadframe is plated with 100% matte tin, which is compatible with standard lead (Pb) free printed circuit board assembly processes. Internally, the device is Pb-free, except for flip-chip high-temperature Pb-based solder balls, currently exempt from RoHS. The device is fully calibrated prior to shipment from the factory.
PCB board at polulu :
https://www.pololu.com/product/1187

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http://www.allegromicro.com/en/Prod...p-Integrated-Conductor-Sensor-ICs/ACS714.aspx
Allegro has models ranging from +/-5A to +/-50A full scale.
Bandwidth is 80kHz.

This model is +/-20A full scale.
ACS714ELCTR-20A-T
It outputs a voltage of 100mV/A.

Link to datasheet :
http://www.allegromicro.com/~/media/Files/Datasheets/ACS714-Datasheet.ashx?la=en

There are many more such sensors.
Farnell has models the wires fit straight through but i am not sure the plug will go through. But you can cut the wires, insert them , solder them again and use some heatshrink tube for isolation.
For example the :

I used this model in the past for a project at work with an accurate opamp circuit that subtracts the ref voltage from the output voltage to get an accurate 0V = 0A output.
I used highly accurate opamps form analog devices but Linear (and TI Burr Brown) also has some very nice op amps.

The HAIS 50-P form LEM

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Bandwidth of 0 to 50kHz.

Datasheet :http://www.farnell.com/datasheets/1685541.pdf

http://www.newark.com/lem/hais-50-p...Categories&searchView=table&iscrfnonsku=false

http://uk.farnell.com/lem/hais-50-p...Categories&searchView=table&iscrfnonsku=false
 
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