MM908E625ACDWB/R2 Motorola, MM908E625ACDWB/R2 Datasheet - Page 31

• Manufacturer Part Number: MM908E625ACDWB/R2
• Description: Integrated Quad Half H-Bridge with Power Supply / Embedded MCU / and LIN Serial Communication
• Manufacturer: Motorola

Offset Chopping
set, HB1 and HB2 will continue to switch on the low-side
MOSFETs with the rising edge of the FGEN signal and HB3 and
Half-Bridge Current Recopy
allow a current recopy feature. This sense source is internally
connected to a shunt resistor. The drop voltage is amplified and
switched to the analog multiplexer.
via bit CSA in the System Control Register.
MOTOROLA ANALOG INTEGRATED CIRCUIT DEVICE DATA
Coil1 Current
Coil2 Current
If bit OFC_EN in the H-Bridge Control Register (HBCTL) is
Each low-side MOSFET has an additional sense output to
The factor for the current sense amplification can be selected
• CSA = 1: Low resolution selected (500 mA measurement
• CSA = 0: High resolution selected (2.5 A measurement
FGEN Input
(MCU PWM
VSUP Line
Current in
Signal)
range).
range).
Freescale Semiconductor, Inc.
For More Information On This Product,
Figure 17. Offset Chopping for Step Motor Control
Go to: www.freescale.com
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
Half-Bridge BEMF Generation
detected in any half-bridge. This recirculation current flows via
the two freewheeling diodes of the power MOSFETs. The
BEMF circuitry detects that and generates a HIGH on the BEMF
output as long as a recirculation current is detected. This signal
provides a flexible and reliable detection of stall in step motor
applications. For this the BEMF circuitry takes advantage of the
instability of the electrical and mechanical behavior of a step
motor when blocked. In addition the signal can be used for open
load detection (absence of this signal) (see
page 32).
The BEMF output is set to “1” if a recirculation current is
17).
HB1
HB2
HB3
HB4
Figure
Coil2…..
Coil1…..
18,
908E625
31