PXS20RM Datasheet, PDF (667/1368 Pages) Freescale Semiconductor, Inc – PXS20 Microcontroller

Flexible Motor Control Pulse Width Modulator Module (FlexPWM)
Writing a logic zero to the INDEP bit configures the PWM output as a pair of complementary channels.
The PWM pins are paired as shown in Figure 25-18 in complementary channel operation. Which signal
is connected to the output pin (PWM23 or PWM45) is determined by the IPOL bit.
VAL2 VAL3
PWM23 Generation
0
PWM45 Generation
1
PWM23
VAL4 VAL5
IPOL
PWM45
Figure 25-18. Complementary Channel Pair
The complementary channel operation is for driving top and bottom transistors in a motor drive circuit,
such as the one in Figure 25-19.
AC
INPUTS
PWM
A0
PWM
B0
PWM
A1
PWM
B1
PWM
A2
PWM
B2
TO
MOTOR
Figure 25-19. Typical 3 Phase AC Motor Drive
Complementary operation allows the use of the deadtime insertion feature.
25.3.3.8 Deadtime insertion logic
Figure 25-20 shows the deadtime insertion logic of each submodule which is used to create
non-overlapping complementary signals when not in independent mode.
Freescale Semiconductor
PXS20 Microcontroller Reference Manual, Rev. 1
25-21