908E626_12 Datasheet, PDF (25/43 Pages) Freescale Semiconductor, Inc – Integrated Stepper Motor Driver with Embedded MCU and LIN Serial Communication

HALF-BRIDGES
Outputs HB1 : HB4 provide four low resistive half-bridge
output stages. The half-bridges can be used in H-Bridge, high
side, or low side configurations.
Reset clears all bits in the H-Bridge Output Register
(HBOUT) owing to the fact that all half-bridge outputs are
switched off.
FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
HB1: HB4 output features:
• Short-circuit (over-current) protection on high side and
low side MOSFETs.
• Current recopy feature (low side MOSFET).
• Over-temperature protection.
• Over-voltage and under-voltage protection.
• Current limitation feature (low side MOSFET).
VSUP
On/Off
Status
High Side Driver
Charge Pump,
Over-temperature Protection,
Over-current Protection
Control
BEMF
On/Off
Status
Current
Limit
Low Side Driver
Current Recopy,
Current Limitation,
Over-current Protection
HBx
GND
Figure 12. Half-bridge Push-Pull Output Driver
Half-bridge Control
Each output MOSFET can be controlled individually. The
general enable of the circuitry is done by setting PSON in the
System Control Register (SYSCTL). HBx_L and HBx_H form
one half-bridge. It is not possible to switch on both MOSFETs
in one half-bridge at the same time. If both bits are set, the
high side MOSFET has a higher priority.
To avoid both MOSFETs (high side and low side) of one
half-bridge being on at the same time, a break-before-make
circuit exists. Switching the high side MOSFET on is inhibited
as long as the potential between gate and V_SS is not below a
certain threshold. Switching the low side MOSFET on is
blocked as long as the potential between gate and source of
the high side MOSFET did not fall below a certain threshold.
Half-bridge Output Register (HBOUT)
Register Name and Address: HBOUT - $01
Bit7 6
5
4
3
2
1 Bit0
Read
HB4_H HB4_L HB3_H HB3_L HB2_H HB2_L HB1_H HB1_L
Write
Reset 0
0
0
0
0
0
0
0
HBx_L — Low Side On / Off Bits
These read / write bits turn on the low side MOSFETs.
Reset clears the HBx_L bits.
• 1 = Low side MOSFET turned on for half-bridge output
x.
• 0 = Low side MOSFET turned off for half-bridge output
x.
Analog Integrated Circuit Device Data
Freescale Semiconductor
908E626
25