DRV8461SPWPR datasheet(28/117 Pages) TI

28 / 117 page

Table 7-15. Custom Microstepping Table Values (continued)

Position (degrees)

Sine Indexer Value

Modified Value (CUSTOM_CURRENTx)

56.25

212

192

67.5

235.6

224

78.75

250.1

240

255

Figure 7-9 shows the corresponding modified current waveform of coil A for one full electrical angle, compared to

waveform generated by sine indexer.

Electrical angle (degrees)

120

150

180

210

240

270

300

330

360

-300

-250

-200

-150

-100

-50

100

150

200

250

300

Sine microstepping indexer

Modified current waveform

Figure 7-9. Customizable Microstepping

7.3.8 Current Regulation

The current through the motor windings is regulated by a PWM current-regulation circuit. When an H-bridge is

enabled, current rises through the winding at a rate dependent on the supply voltage, inductance of the winding,

and the magnitude of the back EMF present. When the current hits the current regulation threshold, the bridge

enters a decay mode for the OFF time to decrease the current, as shown in Figure 7-10. After the off-time

expires, the bridge is re-enabled, starting another PWM cycle.

TRIP

BLANK

OFF

Figure 7-10. Current Chopping Waveform

The PWM regulation current is set by a comparator which monitors the voltage across the current sense

MOSFETs in parallel with the low-side power MOSFETs. When the device is configured with H/W interface, the

current sense MOSFETs are biased with a reference current that is the output of a current-mode sine-weighted

DAC whose full-scale reference current is set by the voltage at the VREF pin. When operating with SPI interface,

two registers (TRQ_DAC and ISTSL) can further scale the reference current.

DRV8461

SLOSE98 – DECEMBER 2022

www.ti.com

Submit Document Feedback

Product Folder Links: DRV8461

DRV8461SPWPR 数据表(PDF) 28 Page - Texas Instruments

DRV8461SPWPR 数据表(HTML) 28 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 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