L6228Q View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'L6228Q' PDF : 32 Pages View PDF
L6228Q
Figure 16. Fast decay mode output stage configurations
Circuit description
A) ON TIME
D01IN1335
B) 1μs DEAD TIME
C) QUASI-SYNCHRONOUS
RECTIFICATION
D) 1μs SLOW DECAY
Figure 17. Slow decay mode output stage configurations
A) ON TIME
D01IN1336
B) 1μs DEAD TIME
C) SYNCHRONOUS
RECTIFICATION
D) 1μs DEAD TIME
4.5
4.5.1
Stepping sequence generation
The phase sequence generator is a state machine that provides the phase and enable
inputs for the two bridges to drive a stepper motor in either full-step or half-step. Two full-
step modes are possible, the normal drive mode where both phases are energized each
step and the wave drive mode where only one phase is energized at a time. The drive mode
is selected by the HALF/FULL input and the current state of the sequence generator as
described below. A rising edge of the CLOCK input advances the state machine to the next
state. The direction of rotation is set by the CW/CCW input. The RESET input resets the
state machine to state 1.
Half-step mode
A high logic level on the HALF/FULL input selects half-step mode. Figure 18 shows the
motor current waveforms and the state diagram for the phase sequencer generator. At
startup or after a RESET the phase sequencer is at state 1. After each clock pulse the state
changes following the sequence 1,2,3,4,5,6,7,8,… if CW/CCW is high (clockwise
movement) or 1,8,7,6,5,4,3,2,… if CW/CCW is low (counterclockwise movement).
Doc ID 14321 Rev 5
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