MC3PHAC Motorola, MC3PHAC Datasheet - Page 14

• Manufacturer Part Number: MC3PHAC
• Description: 3-Phase AC Motor Controller
• Manufacturer: Motorola

MC3PHAC/D
14
NOTE:
Selectable PWM Frequency — The MC3PHAC accommodates four discrete
PWM frequencies and can be changed dynamically while the motor is running.
This resistor can be a potentiometer or a fixed resistor in the range shown in
Table
voltage to the MUX_IN pin while the PWMFREQ_RxD pin is being driven low.
Table 4
associated PWM frequency for each voltage range.
The PWM frequencies are based on a 4.00 MHz frequency applied to the
oscillator input.
Selectable PWM Dead Time — Besides being able to specify the PWM
frequency, the blanking time interval between the on states of the
complementary PWM pairs can also be specified. Refer to the graph in
Figure 9
6.8 k
supplying a voltage to the MUX_IN pin while the DT_FAULTOUT pin is being
driven low. In this way, dead time can be specified with a scaling factor of
2.075 s per volt, with a minimum value of 0.5 s. In PC master software mode,
this value can be selected to be anywhere between 0 and 32 s.
In both standalone and PC master software modes, the dead time value can be
written only once. Further updates of this parameter are locked out until a reset
condition occurs.
Speed Control — The synchronous motor frequency can be specified in real
time to be any value from 1 Hz to 128 Hz by the voltage applied to the SPEED
pin. The scaling factor is 25.6 Hz per volt. This parameter can also be controlled
directly from PC master software in real time.
The SPEED pin is processed by a 24-bit digital filter to enhance the speed
stability in noisy environments. This filter is only activated in standalone mode.
Acceleration Control — Motor acceleration can be specified in real time to be
in the range from 0.5 Hz/second, ranging to 128 Hz/second, by the voltage
applied to the ACCEL pin. The scaling factor is 25.6 Hz/second per volt. This
parameter can also be controlled directly from PC master software in real time.
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4. In standalone mode, the PWM frequency is specified by applying a
shows the required voltage levels on the MUX_IN pin and the
5% pullup resistor. In standalone mode, this is done by
for the resistance value versus dead time.
3-Phase AC Motor Controller
Voltage Input
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1.5 to 2.25 V
2.75 to 3.5 V
0 to 1 V
4 to 5 V
and Corresponding PWM Frequencies
Table 4. MUX_IN Resistance Ranges
PWM Frequency
Figure 9
10.582 kHz
15.873 kHz
21.164 kHz
5.291 kHz
assumes a
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