INA228 datasheet(32/48 Pages) TI

32 / 48 page

The charge value can be read from the CHARGE register as a 40-bit, two's complement value in Coulombs. The

charge value in Coulomb is converted by using Equation 7:

Charge [C] = CURRENT_LSB x CHARGE

(7)

where

• CHARGE is the value read from the CHARGE register.

• CURRENT_LSB is the lsb size of the current calculation as described in Equation 3.

Upon overflow, the ENERGY and CHARGE registers will roll over and start from zero. The register values can

also be reset at any time by setting the RSTACC bit in the CONFIG register.

For a design example using these equations refer to Section 8.2.2.

8.1.3 ADC Output Data Rate and Noise Performance

The INA228 noise performance and effective resolution depend on the ADC conversion time. The device also

supports digital averaging which can further help decrease digital noise. The flexibility of the device to select

ADC conversion time and data averaging offers increased signal-to-noise ratio and achieves the highest

dynamic range with lowest offset. The profile of the noise at lower signals levels is dominated by the system

noise that is comprised mainly of 1/f noise or white noise. The INA228 effective resolution of the ADC can be

increased by increasing the conversion time and increasing the number of averages.

Table 8-2 summarizes the output data rate conversion settings supported by the device. The fastest conversion

setting is 50 µs. Typical noise-free resolution is represented as Effective Number of Bits (ENOB) based on

device measured data. The ENOB is calculated based on noise peak-to-peak values, which assures that full

noise distribution is taken into consideration.

Table 8-2. INA228 Noise Performance

ADC CONVERSION

TIME PERIOD [µs]

OUTPUT SAMPLE

AVERAGING [SAMPLES]

OUTPUT SAMPLE PERIOD

[ms]

NOISE-FREE ENOB

(±163.84-mV)

(ADCRANGE = 0)

NOISE-FREE ENOB

(±40.96-mV)

(ADCRANGE = 1)

0.05

12.4

10.4

0.084

12.6

10.4

150

0.15

13.3

11.4

280

0.28

13.8

11.8

540

0.54

14.2

12.4

1052

1.052

14.5

12.6

2074

2.074

15.3

13.3

4120

4.12

16.0

13.8

0.2

13.1

11.4

0.336

13.9

11.8

150

0.6

14.3

12.2

280

1.12

14.9

12.8

540

2.16

15.1

13.0

1052

4.208

15.8

13.8

2074

8.296

16.1

14.3

4120

16.48

16.5

14.4

INA228

SLYS021 – JANUARY 2021

www.ti.com

Submit Document Feedback

Product Folder Links: INA228

INA228 датащи(PDF) 32 Page - Texas Instruments

INA228 датащи(HTML) 32 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48

датащи скачать

ссылки URL