POWERSTEP01 datasheet(45/92 Pages) STMICROELECTRONICS

Part #	POWERSTEP01

Description	System-in-package integrating microstepping controller and 10 A power MOSFETs

PDF	92 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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45 / 92 page

DocID025022 Rev 5

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powerSTEP01

Phase current control: current mode

Figure 21. Adaptive decay - fast decay tuning

When two or more fast decays are performed with the present target current, the control

system adds a fast decay at the end of every off-time keeping the OFF state duration

constant (tOFF is split into tOFF, SLOW and tOFF, FAST). When the current threshold is

increased by a microstep change (rising step), the system returns to normal decay mode

(slow decay only) and the tFAST value is halved.

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

control system to return to the reset state.

reference current

1st fast decay:

Tfast = TOFF_FAST/8

2nd fast decay (*):

Tfast = TOFF_FAST/4

(*)Note: starting from 2nd fast decay the system combines

fast and slow decay during the OFF phase.

3rd fast decay:

Tfast = TOFF_FAST/2

Ton > TON_MIN

Tfast = TOFF_FAST/2

AM15050v1

POWERSTEP01 Datasheet(PDF) 45 Page - STMicroelectronics