ePWM Submodules
719
SPRUHE8E – October 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
C28 Enhanced Pulse Width Modulator (ePWM) Module
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 formula 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.
For convenience, delay values for various TBCLK options are shown in
Table 7-17. Dead-Band Delay Values in
μ
S as a Function of DBFED and DBRED
Dead-Band Value
Dead-Band Delay in
μ
S
DBFED, DBRED
TBCLK = SYSCLKOUT/1
TBCLK = SYSCLKOUT /2
TBCLK = SYSCLKOUT/4
1
0.01
μ
S
0.03
μ
S
0.05
μ
S
5
0.06
μ
S
0.13
μ
S
0.25
μ
S
10
0.13
μ
S
0.25
μ
S
0.50
μ
S
100
1.25
μ
S
2.50
μ
S
5.00
μ
S
200
2.50
μ
S
5.00
μ
S
10.00
μ
S
400
5.00
μ
S
10.00
μ
S
20.00
μ
S
500
6.25
μ
S
12.50
μ
S
25.00
μ
S
600
7.50
μ
S
15.00
μ
S
30.00
μ
S
700
8.75
μ
S
17.50
μ
S
35.00
μ
S
800
10.00
μ
S
20.00
μ
S
40.00
μ
S
900
11.25
μ
S
22.50
μ
S
45.00
μ
S
1000
12.50
μ
S
25.00
μ
S
50.00
μ
S
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