908E626_09 Datasheet, PDF (27/44 Pages) Freescale Semiconductor, Inc – Integrated Stepper Motor Driver with Embedded MCU and LIN Serial Communication

Coil Current
Half-Bridge
Low-Side Output
FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
H-Bridge low-side
MOSFET will be switched
off if select current limit is
reached.
H-Bridge low-side
MOSFET will be turned on
with each rising edge of
the FGEN input.
t (µs)
FGEN Input
(MCU PWM
Signal)
t (µs)
Minimum 50 µs
t (µs)
Figure 13. Half-bridge Current Limitation
Offset Chopping
If bit OFC_EN in the H-bridge Control Register (HBCTL) is
set, HB1 and HB2 will continue to switch on the low side
MOSFETs with the rising edge of the FGEN signal and HB3
and HB4 will switch on the low side MOSFETs with the falling
edge on the FGEN input. In step motor applications, this
feature allows the reduction of EMI due to a reduction of the
di/dt (Figure 14).
Analog Integrated Circuit Device Data
Freescale Semiconductor
908E626
27