Enhanced PWM (ePWM) Module
Although all combinations are supported, not all are typical usage modes.
lists some classical
dead-band configurations. These modes assume that the DBCTL[IN_MODE] is configured such that
EPWMxA In is the source for both falling-edge and rising-edge delay. Enhanced, or non-traditional modes
can be achieved by changing the input signal source. The modes shown in
fall into the
following categories:
•
Mode 1: Bypass both falling-edge delay (FED) and rising-edge delay (RED) Allows you to fully
disable the dead-band submodule from the PWM signal path.
•
Mode 2-5: Classical Dead-Band Polarity Settings These represent typical polarity configurations that
should address all the active high/low modes required by available industry power switch gate drivers.
The waveforms for these typical cases are shown in
. Note that to generate equivalent
waveforms to
, configure the action-qualifier submodule to generate the signal as shown
for EPWMxA.
•
Mode 6: Bypass rising-edge-delay and Mode 7: Bypass falling-edge-delay Finally the last two
entries in
show combinations where either the falling-edge-delay (FED) or rising-edge-
delay (RED) blocks are bypassed.
Table 15-34. Classical Dead-Band Operating Modes
DBCTL[POLSEL]
DBCTL[OUT_MODE]
Mode
Mode Description
(1)
S3
S2
S1
S0
1
EPWMxA and EPWMxB Passed Through (No Delay)
x
x
0
0
2
Active High Complementary (AHC)
1
0
1
1
3
Active Low Complementary (ALC)
0
1
1
1
4
Active High (AH)
0
0
1
1
5
Active Low (AL)
1
1
1
1
6
EPWMxA Out = EPWMxA In (No Delay)
0 or 1
0 or 1
1
0
EPWMxB Out = EPWMxA In with Falling Edge Delay
7
EPWMxA Out = EPWMxA In with Rising Edge Delay
0 or 1
0 or 1
1
0
EPWMxB Out = EPWMxB In with No Delay
(1)
These are classical dead-band modes and assume that DBCTL[IN_MODE] = 0,0. That is, EPWMxA in is the source for both the
falling-edge and rising-edge delays. Enhanced, non-traditional modes can be achieved by changing the IN_MODE configuration.
1536
Pulse-Width Modulation Subsystem (PWMSS)
SPRUH73H – October 2011 – Revised April 2013
Copyright © 2011–2013, Texas Instruments Incorporated