MC3PHAC/D
Features
MOTOROLA
3-Phase AC Motor Controller
13
Selectable Base Frequency
— Alternating current (ac) motors are designed
to accept rated voltage at either 50 or 60 Hz, depending on what region of the
world they were designed to be used. The MC3PHAC can accommodate both
types of motors by allowing the voltage profile to reach maximum value at either
50 or 60 Hz. This parameter can be specified at initialization in standalone
mode, or it can be changed at any time in PC master software mode.
Selectable PWM Polarity
—
The polarity of the PWM outputs may be specified
such that a logic high on a PWM output can either be the asserted or negated
state of the signal. In standalone mode, this parameter is specified at
initialization and applies to all six PWM outputs. In PC master software mode,
the polarity of the top PWM signals can be specified separately from the polarity
of the bottom PWM signals.
This specification can be done at any time, but once it is done, the polarities are
locked and cannot be changed until a reset occurs. Also, any commands from
PC master software that would have the effect of enabling PWMs are
prevented by the MC3PHAC until the polarity has been specified.
In standalone mode, the base frequency and PWM polarity are specified at the
same time during initialization by connecting either pin 25, 26, 27, or 28
exclusively to the PWMPOL_BASEFREQ input. During initialization, pins 25,
26, 27, and 28 are cycled one at a time to determine which one has been
connected to the PWMPOL_BASEFREQ input.
Table 3
shows the selected PWM polarity and base frequency as a function of
which pin connection is made. Refer to the standalone mode schematic,
Figure 8
. Only one of these jumpers (JP1–JP4) can be connected at any one
time.
NOTE:
It is not necessary to break this connection once the initialization phase has
been completed. The MC3PHAC will function properly while this connection is
in place.
Table 3. PWM Polarity and Base Frequency
Specification in Standalone Mode
Pin Connected to
PWMPOL_BASEFREQ Pin
PWM Polarity
Base
Frequency
MUX_IN (JP1)
Logic low = on
50 Hz
SPEED (JP2)
Logic high = on
50 Hz
ACCEL (JP3)
Logic low = on
60 Hz
DC_BUS (JP4)
Logic high = on
60 Hz
F
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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