SPRUJD3A July 2025 – October 2025 F28E120SB , F28E120SC
The configuration options for the dead-band submodule are shown in Figure 15-30.
Although all combinations are supported, not all are typical usage modes. Table 15-8 documents some classical dead-band configurations. These modes assume that the DBCTL[IN_MODE] is configured such that MCPWMx_yA 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 Table 15-8 fall into the following categories:
Figure 15-31 shows waveforms for typical cases where 0% < duty < 100%.
| Mode | Mode Description | DBCTL[POLSEL] | DBCTL[OUT_MODE] | ||
|---|---|---|---|---|---|
| S3 | S2 | S1 | S0 | ||
| 1 | MCPWMx_yA and MCPWMx_yB 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 | MCPWMx_yA Out = MCPWMx_yA In (No Delay) | 0 or 1 | 0 or 1 | 0 | 1 |
| MCPWMx_yB Out = MCPWMx_yA In with Falling-Edge Delay | |||||
| 7 | MCPWMx_yA Out = MCPWMx_yA In with Rising-Edge Delay | 0 or 1 | 0 or 1 | 1 | 0 |
| MCPWMx_yB Out = MCPWMx_yB In with No Delay | |||||
| Mode Description | DBCTL[DEDB-MODE] | DBCTL[OUTSWAP] | |
|---|---|---|---|
| S8 | S6 | S7 | |
| MCPWMx_yA and MCPWMx_yB signals are as defined by OUT-MODE bits. | 0 | 0 | 0 |
| MCPWMx_yA = A-path as defined by OUT-MODE bits. | 0 | 0 | 1 |
| MCPWMx_yB = A-path as defined by OUT-MODE bits (rising-edge delay or delay-bypassed A-signal path) | |||
| MCPWMx_yA = B-path as defined by OUT-MODE bits (falling-edge delay or delay-bypassed B-signal path) | 0 | 1 | 0 |
| MCPWMx_yB = B-path as defined by OUT-MODE bits | |||
| MCPWMx_yA = B-path as defined by OUT-MODE bits (falling-edge delay or delay-bypassed B-signal path) | 0 | 1 | 1 |
| MCPWMx_yB = A-path as defined by OUT-MODE bits (rising-edge delay or delay-bypassed A-signal path) | |||
| Rising-edge delay applied to MCPWMx_yA / MCPWMx_yB as selected by S4 switch (IN-MODE bits) on A signal path only. | 0 | X | X |
| Falling-edge delay applied to MCPWMx_yA / MCPWMx_yB as selected by S5 switch (IN-MODE bits) on B signal path only. | |||
| Rising-edge delay and falling-edge delay applied to source selected by S4 switch (IN-MODE bits) and output to B signal path only.(1) | 1 | X | X |
Figure 15-31 Dead-Band Waveforms for Typical Cases (0% < Duty < 100%)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 the value represents the number of TBCLK (time-base clock) pulses by which a signal edge is delayed. For example, the formula to calculate falling-edge-delay and rising-edge-delay is:
FED = DBFED × TTBCLK
RED = DBRED × TTBCLK
Where TTBCLK is the period of TBCLK, the prescaled version of MCPWMCLK.
For convenience, delay values for various TBCLK options are shown in Table 15-10. The MCPWM input clock frequency that these delay values been computed by is 100MHz.
| Dead-Band Value | Dead-Band Delay (μs) | ||
|---|---|---|---|
| DBFED, DBRED | TBCLK = PWMCLK/1 | TBCLK = PWMCLK /2 | TBCLK = PWMCLK/4 |
| 1 | 0.01 | 0.02 | 0.04 |
| 5 | 0.05 | 0.10 | 0.20 |
| 10 | 0.10 | 0.20 | 0.40 |
| 100 | 1.00 | 2.00 | 4.00 |
| 200 | 2.00 | 4.00 | 8.00 |
| 400 | 4.00 | 8.00 | 16.00 |
| 500 | 5.00 | 10.00 | 20.00 |
| 600 | 6.00 | 12.00 | 24.00 |
| 700 | 7.00 | 14.00 | 28.00 |
| 800 | 8.00 | 16.00 | 32.00 |
| 900 | 9.00 | 18.00 | 36.00 |
| 1000 | 10.00 | 20.00 | 40.00 |