mc9s12e256 Freescale Semiconductor, Inc, mc9s12e256 Datasheet - Page 363

• Manufacturer Part Number: mc9s12e256
• Description: Hcs12 Microcontrollers 16-bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

If both D flip-flops latch low, DT0 = 0, DT1 = 0, during deadtime periods if current is large and flowing
out of the complementary circuit. See
during deadtime periods if current is also large and flowing into the complementary circuit. However,
under low-current, the output voltage of the complementary circuit during deadtime is somewhere between
the high and low levels. The current cannot free-wheel throughout the opposition anti-body diode,
regardless of polarity, giving additional distortion when the current crosses zero. Sampled results will be
DT0 = 0 and DT1 = 1. Thus, the best time to change one PWM value register to another is just before the
current zero crossing.
Freescale Semiconductor
HIGH NEGATIVE CURRENT
HIGH POSITIVE CURRENT
LOW POSITIVE CURRENT
PWM0
PWM1
LOAD VOLTAGE WITH
LOAD VOLTAGE WITH
LOAD VOLTAGE WITH
LOAD VOLTAGE WITH
NEGATIVE CURRENT
PWM TO BOTTOM
Figure 11-55. Current-Status Sense Scheme for Deadtime Correction
TRANSISTOR
TRANSISTOR
PWM TO TOP
DEADTIME
T = DEADTIME INTERVAL BEFORE ASSERTION OF TOP PWM
B = DEADTIME INTERVAL BEFORE ASSERTION OF BOTTOM PWM
Figure 11-56. Output Voltage Waveforms
NEGATIVE
CURRENT
POSITIVE
CURRENT
MC9S12E256 Data Sheet, Rev. 1.08
Figure
T
VOLTAGE
SENSOR
11-55. If both D flip-flops latch the high, DT0 = 1, DT1 = 1,
B
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
IS0 PIN
T
PWM0
PWM1
B
D
D
CLK
CLK
Q
Q
V+
DT0
DT1
POSITIVE
CURRENT
NEGATIVE
CURRENT
363