12. Timer (Three-phase Motor Control Timer Function)
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page 134
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Figure 12.33 Triangular Wave Modulation Operation
The three-phase motor control timer function is enabled by setting the INV02 bit in the INVC0 register to 1.
When this function is on, timer B2 is used to control the carrier wave, and timers A4, A1 and A2 are used to
__ ___ ___
control three-phase PWM outputs (U, U, V, V, W and W). The dead time is controlled by a dedicated dead-
time timer. Figure 12.33 shows the example of triangular modulation waveform, and Figure 12.34 shows
the example of sawtooth modulation waveform.
Start trigger signal
for timer A4
(1)
Timer B2
U phase
Triangular wave
Signal wave
U phase
output signal
(1)
m
nn
p
p
m
U phase
U phase
U phase
INV14 = 0
Triangular waveform as a Carrier Wave
Timer A4
one-shot pulse
(1)
INV14 = 1
Dead time
Dead time
Rewrite registers IDB0 and IDB1
NOTE:
1. Internal signals. See Figure 12.25.
Examples of PWM output change are:
(1)When INV11 = 1 (three-phase mode 1)
· INV01 = 0 and ICTB2 = 2
16
(the timer B2 interrupt is generated
every two times the timer B2 underflows),
or INV01 = 1, INV00 = 1, and ICTB2=1
16
(the timer B2 interrupt is
generated at the falling edge of the timer A1 reload control signal.)
· Default value of the timer: TA41 = m, TA4 = m.
Registers TA4 and TA41 are changed whenever the timer B2
interrupt is generated.
First time, TA41 = n, TA4 = n. Second time, TA41 = p, TA4 = p.
· Default values of registers IDB0 and IDB1:
DU0 = 1, DUB0 = 0, DU1 = 0, DUB1 = 1.
They are changed to DU0 = 1, DUB0 = 0, DU1= 1 and DUB1 = 0
when the third timer B2 interrupt is generated.
(2)When INV11 = 0 (three-phase mode 0)
· INV01 = 0, ICTB2 = 1
16
(the timer B2 interrupt is generated
whenever timer B2 underflows)
· Default value of the timer: TA4 = m. The TA4 register is changed
whenever the timer B2 interrupt is generated.
First time: TA4 = m. Second tim:, TA4 = n.
Third time: TA4 = n. Fourth time: TA4 = p.
Fifth time: TA4 = p.
· Default values of registers IDB0 and IDB1:
DU0 = 1, DUB0 = 0, DU1 = 0, DUB1 = 1.
They are changed to DU0 = 1, DUB0 = 0, DU1 = 1, and DUB1 = 0
when the sixth timer B2 interrupt is generated.
TB2S bit in the
TABSR register
INV13
(INV11=1(three-phase
mode 1))
The above applies under the following conditions:
INVC0 = 00XX11XX
2
(X varies depending on each system) and INVC1 = 010XXXX0
2
.
U phase
output signal
(1)
(“L” active)
(“H” active)
The value written to registers TA4 and TA41 becomes effective at the rising edge of the timer A1 reload control signal.
Transfer the values
to the three-phase
output shift register
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