L9908 datasheet(89/152 Pages) STMICROELECTRONICS

89 / 152 page

Table 81. CSM gain

CSM input range

FULL SCALE

GAIN

output range: 0-5V

GAIN

output range: 0-3.3V

±7 mV

242.8856

160.2985

±18 mV

121.3824

80.1094

±36 mV

60.60079

39.99503

±90 mV

24.24032

15.99801

±160 mV

13.4661

8.887295

±300 mV

7.574629

4.999069

Gain is calculated as the ratio between CSO output range (either 3.3 V or 5 V) and the input Full Scale range.

Values in Table 81 are valid only in case OFS = 1024 lsb. OFS = 0 lsb and OFS = 90 lsb have to be used in case

of DC-link configuration; in this case input voltage can be only positive and gain values of Table 81 must be

multiplied by 2.

Total error:

The CM A/D – D/A Chain total error contribution is given by:

Table 82. Current monitor A/D - D/A total error

Symbol

Parameter

Min Typ Max Unit

Notes

Current Monitor Accuracy

CM_gain_err

CM Gain Error

-2

(1)

All input ranges

CM_offset_err CM Offset Error

-2

-3

-6

(1)

Each value refers to the corresponding CM differential voltage input

range

1. Ex.

•

Vin = ISn+ - ISn- = -70 mV

•

CM_in_range_diff = ±90 mV

•

CM_out_range = 3.3 V

•

CSM_OFS = 1024

•

VOFS = 1024*1.611 mV = 1.65 V

•

G = 15.99801

•

V_CM_total_error = ±2 mV ± (2%*70 mV) = ±2 mV ±1.4 mV = ±3.4 mV

•

Vout (ideal) = 1.65 V-70 mV*15.99801 = 530 mV

•

Vout (minimum) = Vout (ideal) – (3.40 mV*15.99801) = 475.60 mV

•

Vout (maximum) = Vout (ideal) + (3.40 mV*15.99801) = 584.39 mV

Noise Performance

Table 83. Current monitor chain noise performance

Symbol

Parameter

Min Typ Max

Unit

Notes

CM_noise_performance

CM integrated output noise voltage

9.7

4.5

2.6

1.4

mV (RMS) Application information(1)

L9908

Functional description

DS13546 - Rev 5

page 89/152

L9908 数据表(PDF) 89 Page - STMicroelectronics

L9908 数据表(HTML) 89 Page - STMicroelectronics

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 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

数据表下载