L6480 datasheet(37/73 Pages) STMICROELECTRONICS

Part #	L6480

Description	The L6480, realized in analog mixed signal technology, is an advanced fully integrated solution suitable for driving two-phase bipolar stepper motors with microstepping.

PDF	73 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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37 / 73 page

L6480

Phase current control

Doc ID 023278 Rev 3

37/73

Figure 16.

Current distortion and compensation

The optimization can be enabled setting high the LSPD_OPT bit in the MIN_SPEED register

(Section 9.1.8) and is active in a speed range from zero to MIN_SPEED. When low speed

optimization is enabled, speed profile minimum speed is forced to zero.

7.4

BEMF compensation

Using the speed information, a compensation curve is added to the amplitude of the voltage

waveform applied to the motor winding in order to compensate the BEMF variations during

acceleration and deceleration (see Figure 17).

The compensation curve is approximated by a stacked line with a starting slope (ST_SLP)

when speed is lower than a programmable threshold speed (INT_SPEED) and a fine slope

(FN_SLP_ACC and FN_SLP_DEC) when speed is greater than the threshold speed (see

sections 9.1.11, 9.1.12, 9.1.13 and 9.1.14).

L6480 Datasheet(PDF) 37 Page - STMicroelectronics