•
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 3-14. Classical Dead-Band Operating Modes
Mode
Mode Description
DBCTL[POLSEL]
DBCTL[OUT_MODE]
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
0
1
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
The dead-band submodule supports independent values for rising-edge (RED) and falling-edge (FED) delays.
The amount of delay is programmed using the DBRED and DBFED registers. These are 10-bit registers and
their value represents the number of time-base clock, TBCLK, periods a signal edge is delayed by. For example,
the formulas to calculate falling-edge-delay and rising-edge-delay are:
FED = DBFED × T
TBCLK
RED = DBRED × T
TBCLK
Where T
TBCLK
is the period of TBCLK, the prescaled version of SYSCLKOUT.
When half-cycle clocking is enabled, the formula to calculate the falling-edge-delay and rising-edge-delay
becomes:
FED = DBFED × T
TBCLK
/2
RED = DBRED × T
TBCLK
/2
shows waveforms for typical cases where 0% < duty < 100%.
Enhanced Pulse Width Modulator (ePWM) Module
280
TMS320x2806x Microcontrollers
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
Copyright © 2022 Texas Instruments Incorporated
Содержание TMS320 2806 Series
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