ST92141 STMicroelectronics, ST92141 Datasheet - Page 120

• Manufacturer Part Number: ST92141
• Description: 8/16-bit Mcu For 3-phase Ac Motor Control
• Manufacturer: STMicroelectronics

ST92141 - 3-PHASE INDUCTION MOTOR CONTROLLER (IMC)
INDUCTION MOTOR CONTROLLER (Cont’d)
Repetition Down-Counter
Both in Zerocentered and Classical working mode,
the four Compare registers (one Compare 0 and
three for the U, V and W phases) are updated
when the PWM counter value is zero and the 8-bit
Repetition Down-Counter has reached zero value
by counting or by software programming (see
PCR2 register).
This means that data transits from the Preload
Compare registers to the Compare registers every
N cycles of the PWM Counter, where N is the val-
ue of the 8-bit Repetition register (N=1, 2, .., 256).
7.4.3.4 Dead Time Generator
For each phase there is one 6-bit Dead Time gen-
erator.
It generates two output signals: h and l.
The h output signal is the same as the input phase
signal except for the rising edge, which is delayed
relatively to the input signal rising edge.
Figure 67. Dead Time waveforms
120/179
U
Uh
Ul
9
Delay
The l output signal is the opposite of the input
phase signal except the rising edge which is de-
layed relatively to the input signal falling edge.
The delay is the same for each phase (U, V, W)
and its value is:
delay = T x N
where T is the period of the Dead Time Generator
input clock (INTCLK divided by 2) and N is the 6-
bit number in the Dead Time register.
If the DTE bit in PCR0 register is reset, the Dead
Time Generator is disabled. This means that no
delays are added to the l complemented outputs.
Figure 67
phase.
If the delay is greater than the width of the active
phase (l or h) then the corresponding pulse is not
generated.
See
Figure 68
shows an example waveform of the U
and
Delay
Figure
69.
5V
0V
5V
0V
5V
0V