AN1857 Freescale Semiconductor / Motorola, AN1857 Datasheet - Page 16

• Manufacturer Part Number: AN1857
• Description: A 3-Phase ac Induction Motor Control System Based on the MC68HC908MR32
• Manufacturer: Freescale Semiconductor / Motorola

Application Note
Gate Drive
16
Gate drive signals, from the control board to the power stage, are
passed from controller to the power stage through high-speed digital
optocouplers. Analog feedback signals from the power stage to the
controller board are passed through HCNR201 high-linearity analog
optocouplers. Ground signals between the control board and power
stage are separated by the optocouplers’ galvanic isolation barrier.
Power requirements for the control board’s circuitry are satisfied with a
single external 12-Vdc power supply.
The power supply is connected to the optoisolation board and fed to the
control board through the 40-pin ribbon cable connector. Excitation for
the power stage side circuitry is supplied to the power stage through the
40-pin output connector located on the optoisolation board.
In addition to the usual motor control signals, an MC68HC705JJ7 serves
as a serial link, which allows the controller board’s software to identify
the configuration of the optoisolation board and power stage boards and
pass configuration information to the control board for processing and
system configuration checking.
Freescale Semiconductor, Inc.
For More Information On This Product,
SIGNALS TO
CONTROL
BOARD
Figure 8. Optoisolation Board Block Diagram
Go to: www.freescale.com
dc POWER
12-15 Vdc
CONVERTER
dc TO dc
BREAK CONTROL
CURRENT SENSE
PFC CONTROL
BUS CURRENT
BUS VOLTAGE
PHASE A, B, C
TEMP. SENSE
ZERO-CROSS
PFC INHIBIT
BACK-EMF
(ANALOG)
BOARD ID
(DIGITAL)
PWM(6)
AUX. I/O
SERIAL
SIGNALS TO
POWER
BOARD
MOTOROLA
AN1857