ACS772 datasheet(32/41 Pages) ALLEGRO

32 / 41 page

High Accuracy, Hall-Effect-Based, 200 kHz Bandwidth,

Galvanically Isolated Current Sensor IC with 100 µΩ Current Conductor

ACS772

Allegro MicroSystems, LLC

955 Perimeter Road

Manchester, NH 03103-3353 U.S.A.

www.allegromicro.com

TOTAL OUTPUT ERROR (ETOT)

The difference between the current measurement from the sensor

IC and the actual current (IP), relative to the actual current. This

is equivalent to the difference between the ideal output voltage

and the actual output voltage, divided by the ideal sensitivity,

relative to the current flowing through the primary conduction

path:

ETOT(IP) =

VIOUT(IP) – VIOUT(ideal)(IP)

Sensideal × IP

× 100(%)

where

VIOUT(ideal)(IP) = VIOUT(Q) + (SensIDEAL × IP )

The Total Output Error incorporates all sources of error and is a

function of IP.

At relatively high currents, ETOT will be mostly due to sensitiv-

ity error, and at relatively low currents, ETOT will be mostly due

to Offset Voltage (VOE). In fact, as IP approaches zero, ETOT

approaches infinity due to the offset voltage. This is illustrated

in Figure 1 and Figure 2. Figure 1 shows a distribution of output

voltages versus IP at 25°C and across temperature. Figure 2

shows the corresponding ETOT versus IP.

0 A

Decreasing

VIOUT (V)

Accuracy Across

Temperature

Accuracy Across

Temperature

Accuracy Across

Temperature

Accuracy at

25°C Only

Accuracy at

25°C Only

Accuracy at

25°C Only

Increasing

VIOUT (V)

Ideal VIOUT

IPR(min)

IPR(max)

+IP (A)

–IP (A)

VIOUT(Q)

Full Scale IP

Figure 1: Output Voltage versus Sensed Current

Figure 2: Total Output Error versus Sensed Current

+IP

–IP

+ETOT

–ETOT

Across Temperature

25°C Only

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