L6472 datasheet(36/69 Pages) STMICROELECTRONICS

Numer części	L6472

Szczegółowy opis	dSPIN fully integrated microstepping motor driver

PDF	69 Pages

Scroll/Zoom	100%

Producent	STMICROELECTRONICS [STMicroelectronics]

Strona internetowa	http://www.st.com

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36 / 69 page

Phase current control

L6472

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Doc ID 022729 Rev 1

7.3

Auto-adjusted fast decay during the falling steps

When the target current is decreased by a microstep change (falling step), the device

performs a fast decay in order to reach the new value as fast as possible. Anyway,

exceeding the fast duration may cause a strong ripple on the step change. The L6472

automatically adjusts these fast decays reducing the current ripple.

At reset, the fast decay value (tFALL) is set to FALL_STEP/4 (T_FAST register). The tFALL

value is doubled every time, within the same falling step, an extra fast decay is necessary to

obtain an ON time greater than TON_MIN. The maximum tFALL value is equal to

FALL_STEP.

At the next falling step, the system uses the last tFALL value of the previous falling step.

Stopping the motor or reaching the current sinewave zero crossing causes the current

control system to return to the reset state.

Figure 18.

Adaptive decay switch from normal to slow+fast decay mode and

viceversa

L6472 Arkusz danych(PDF) 36 Page - STMicroelectronics