SPRACN0F October 2021 – March 2023 TMS320F280021 , TMS320F280021-Q1 , TMS320F280023 , TMS320F280023-Q1 , TMS320F280023C , TMS320F280025 , TMS320F280025-Q1 , TMS320F280025C , TMS320F280025C-Q1 , TMS320F280033 , TMS320F280034 , TMS320F280034-Q1 , TMS320F280036-Q1 , TMS320F280036C-Q1 , TMS320F280037 , TMS320F280037-Q1 , TMS320F280037C , TMS320F280037C-Q1 , TMS320F280038-Q1 , TMS320F280038C-Q1 , TMS320F280039 , TMS320F280039-Q1 , TMS320F280039C , TMS320F280039C-Q1 , TMS320F280040-Q1 , TMS320F280040C-Q1 , TMS320F280041 , TMS320F280041-Q1 , TMS320F280041C , TMS320F280041C-Q1 , TMS320F280045 , TMS320F280048-Q1 , TMS320F280048C-Q1 , TMS320F280049 , TMS320F280049-Q1 , TMS320F280049C , TMS320F280049C-Q1 , TMS320F28374D , TMS320F28374S , TMS320F28375D , TMS320F28375S , TMS320F28375S-Q1 , TMS320F28376D , TMS320F28376S , TMS320F28377S , TMS320F28377S-Q1 , TMS320F28378D , TMS320F28378S , TMS320F28379D , TMS320F28379D-Q1 , TMS320F28379S , TMS320F28384D , TMS320F28384S , TMS320F28386D , TMS320F28386S , TMS320F28388D , TMS320F28388S , TMS320F28P650DH , TMS320F28P650DK , TMS320F28P650SH , TMS320F28P650SK , TMS320F28P659DH-Q1 , TMS320F28P659DK-Q1 , TMS320F28P659SH-Q1
All PWM-controlled power topologies are inherently bandwidth limited by the ability of the controller to place the PWM edge as close as possible to the mathematical solution of the control law. Whatever error exists from “rounding” the solution created in the form of an output PWM signal dictates the maximum efficiency that can be realized in the system.
In this sense, it may be helpful to think of the PWM as a type of DAC with a fixed resolution. Any error that results in the selection of the next available PWM edge placement would then be equivalent to quantization error term that is inherent to any DAC. Therefore, the minimum time step that can be achieved by a PWM module can be translated into “bits” of resolution of this equivalent DAC.
As shown in #GUID-DB4B8E17-5B92-4388-A1BE-399BA1D9B530/T5843526-114, the increase of resolution of the C2000 MCU HRPWM vs a traditional PWM is very apparent, increasing the effective resolution by approximately 6 bits.
PWM Freq (kHz) |
Regular
Resolution (PWM) 100 MHz EPWMCLK |
High Resolution (HRPWM) | ||
---|---|---|---|---|
Bits | % Error | Bits | % Error | |
20 | 12.3 | 0.02 | 18.1 | 0.000 |
50 | 11 | 0.05 | 16.8 | 0.001 |
100 | 10 | 0.1 | 15.8 | 0.002 |
150 | 9.4 | 0.15 | 15.2 | 0.003 |
200 | 9 | 0.2 | 14.8 | 0.004 |
250 | 8.6 | 0.25 | 14.4 | 0.005 |
500 | 7.6 | 0.5 | 13.4 | 0.009 |
1000 | 6.6 | 1 | 12.4 | 0.018 |
1500 | 6.1 | 1.5 | 11.9 | 0.027 |
2000 | 5.6 | 2 | 11.4 | 0.036 |