ePWM
C2000 Microcontroller Workshop - Control Peripherals 7 - 23
the gate via the by-pass diode and closing time is therefore not affected. While this passive
approach offers an inexpensive solution that is independent of the control microprocessor, it is
imprecise, the component parameters must be individually tailored to the power converter, and it
cannot adapt to changing system conditions.
The second approach to shoot-through control separates transitions on complimentary PWM
signals with a fixed period of time. This is called dead-band. While it is possible to perform
software implementation of dead-band, the C28x offers on-chip hardware for this purpose that
requires no additional CPU overhead. Compared to the passive approach, dead-band offers more
precise control of gate timing requirements. In addition, the dead time is typically specified with
a single program variable that is easily changed for different power converters or adapted on-line.
ePWM Dead-Band Sub-Module Registers
(lab file: EPwm.c)
Rising Edge Delay = T
TBCLK
x DBRED
Falling Edge Delay = T
TBCLK
x DBFED
Name Description Structure
DBCTL Dead-Band Control EPwmxRegs.DBCTL.all =
DBRED 10-bit Rising Edge Delay EPwmxRegs.DBRED =
DBFED 10-bit Falling Edge Delay EPwmxRegs.DBFED =
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