PSCLK
OSHT
EPWMxA in
EPWMxA out
Prog. pulse width
(OSHTWTH)
Start OSHT pulse
Sustaining pulses
PSCLK
EPWMxA
EPWMxB
EPWMxA
EPWMxB
Enhanced PWM (ePWM) Module
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15.2.2.7.4 Waveforms
Figure 15-38 shows simplified waveforms of the chopping action only; one-shot and duty-cycle control are
not shown. Details of the one-shot and duty-cycle control are discussed in the following sections.
Figure 15-38. Simple PWM-Chopper Submodule Waveforms Showing Chopping Action Only
15.2.2.7.4.1 One-Shot Pulse
The width of the first pulse can be programmed to any of 16 possible pulse width values. The width or
period of the first pulse is given by:
T
1stpulse
= T
SYSCLKOUT
× 8 × OSHTWTH
Where T
SYSCLKOUT
is the period of the system clock (SYSCLKOUT) and OSHTWTH is the four control bits
(value from 1 to 16)
Figure 15-39 shows the first and subsequent sustaining pulses.
Figure 15-39. PWM-Chopper Submodule Waveforms Showing the First Pulse and
Subsequent Sustaining Pulses
1540
Pulse-Width Modulation Subsystem (PWMSS) SPRUH73H–October 2011–Revised April 2013
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