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2.6.4.2
Duty Cycle Control
Duty
1/8
Duty
2/8
Duty
3/8
Duty
4/8
Duty
5/8
Duty
6/8
Duty
7/8
PSCLK
12.5%
25%
37.5%
50%
62.5%
75%
87.5%
PSCLK Period
PSCLK
period
PWM-Chopper (PC) Submodule
Pulse transformer-based gate drive designs need to comprehend the magnetic properties or
characteristics of the transformer and associated circuitry. Saturation is one such consideration. To assist
the gate drive designer, the duty cycles of the second and subsequent pulses have been made
programmable. These sustaining pulses ensure the correct drive strength and polarity is maintained on the
power switch gate during the on period, and hence a programmable duty cycle allows a design to be
tuned or optimized via software control.
characteristics of the transformer and associated circuitry. Saturation is one such consideration. To assist
the gate drive designer, the duty cycles of the second and subsequent pulses have been made
programmable. These sustaining pulses ensure the correct drive strength and polarity is maintained on the
power switch gate during the on period, and hence a programmable duty cycle allows a design to be
tuned or optimized via software control.
shows the duty cycle control that is possible by programming the CHPDUTY bits. One of
seven possible duty ratios can be selected ranging from 12.5% to 87.5%.
Figure 2-34. PWM-Chopper Submodule Waveforms Showing the Pulse Width (Duty Cycle) Control of
Sustaining Pulses
ePWM Submodules
58
SPRU791D – November 2004 – Revised October 2007