DPWM Control Register 0 (DPWMCTRL0)
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SNIU028A – February 2016 – Revised April 2016
Copyright © 2016, Texas Instruments Incorporated
Digital Pulse Width Modulator (DPWM)
2.15.6 Master Sync Control Select
The MASTER_SYNC_CNTL_SEL bit selects where the sync output of the DPWM channel comes from.
The default value, 0, causes the sync delay to come from the Phase Trigger register. This is useful for
systems that have fixed intervals between phases, such as interleaved PFC and hard switching full bridge.
See
Putting a 1 into this bit causes the master sync output to be controlled by the Filter output.
This bit is duplicated in the AMS registers.
2.15.7 Master Sync Slave Enable
Setting the MSYNC_SLAVE_EN bit enables the DPWM channel to be slaved to the sync output of another
DPWM channel. This bit works together with the DPWMx_SYNC_SEL bits in the DPWMMUX register in
. The sample code below makes DPWM1 a slave to DPWM0:
LoopMuxRegs.DPWMMUX.bit.DPWM1_SYNC_SEL = 0; //DPWM1 is slave to DPWM0
Dpwm1Regs.DPWMCTRL0.bit.MSYNC_SLAVE_EN = 1; //enable slave mode for DPWM1
This bit is not duplicated in the AMS registers.
2.15.8 D Enable
Normally, the Filter Duty (D) is used to set the on-time of DPWM pins directly. In other words, OnTime =
D. The D_ENABLE bit can be used to make the OnTime = 1-D instead.
A default value (0) causes the output of the Filter to be used directly for DPWM output calculations. So in
multi mode, for example, the DPWMA and B on-times would increase as the Filter Duty increases.
If the D_ENABLE bit is set, however, the Filter Duty is subtracted from the period register. In this case, as
the Filter Duty increases from zero to full range, the on-time will decrease from 100% of the period to 0%
of the period.
This bit is not duplicated in the AMS registers.
2.15.9 Resonant Mode Fixed Duty Enable
The RESON_MODE_FIXED_DUTY_EN bit only controls the duty cycle width in the resonant modes. With
the default (0) value, the duty cycle comes from the filter directly. This is for use above the lower resonant
frequency, Fmin, and provides a duty cycle that fills half the period minus a fixed dead time.
Setting this bit causes the pulse width to be derived from the Auto Switch High Upper Threshold Register.
This bit is generally only set for LLC for the Sync FETs in the mode where the output frequency is below
the lowest resonant frequency of the circuit. At this point any increases in pulse width are not beneficial,
so they are stopped. There is also a waveform showing the modes in
.
This bit is duplicated in the AMS registers.
2.15.10 DPWM A and B Fault Priority
The PWM_A_FLT_POL and PWM_B_FLT_POL bits increase the flexibility of the DPWM by permitting
arbitrary output states for the DPWM pins in case of a fault. The values in these bits will also appear on
these pins when the DPWM is disabled. These values actually appear on the output of the Fault Module in
the DPWM. Therefore, if the IntraMux or Edge Generation units are used, the same value may not appear
on the output of the DPWM.
These bits do not affect the DPWM status after device reset. After reset, all DPWM pins are configured as
outputs and actively driven low.
These bits are not duplicated in the AMS registers.