This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

  • Resolved

TIDM-02008: deadband swap usage meaning

Intellectual 1860 points

Replies: 2

Views: 31

Part Number: TIDM-02008

hi expert,

I see there is enable swap of high frequency PWM at negativeZeroCrossing3, which let PWMxA= PWMxB, PWMxB= PWMxA.

 if(acSine < threshold_NZC2)
            {
                state_slew=0;
                pwm_SwState.enum_pwmSwState=pwmSwState_negativeZeroCrossing3;
                // Enable xA xB Swap
                ENABLE_SWAP_DEADBAND_OUTPUT(HIGH_FREQ_PWM1_BASE);
                ENABLE_SWAP_DEADBAND_OUTPUT(HIGH_FREQ_PWM2_BASE);
                ENABLE_SWAP_DEADBAND_OUTPUT(HIGH_FREQ_PWM3_BASE);
                softstart_duty=0;

                gi.i10=0;
                gi.i6=1;
                gi.Ki=0;
                gi_out=0;
            }

And remain the setting, after that, disable the swap of high frequency PWM at positiveZeroCrossing3

 if(acSine > threshold_PZC2 )
            {
                pwm_SwState.enum_pwmSwState=pwmSwState_positiveZeroCrossing3;
                state_slew=0;
                softstart_duty=0;

                // Dead band output swap disabled
                DISABLE_SWAP_DEADBAND_OUTPUT(HIGH_FREQ_PWM1_BASE);
                DISABLE_SWAP_DEADBAND_OUTPUT(HIGH_FREQ_PWM2_BASE);
                DISABLE_SWAP_DEADBAND_OUTPUT(HIGH_FREQ_PWM3_BASE);

                gi.i10=0;
                gi.i6=1;
                gi_out=0;
                gi.Ki=0;
            }

I really don't understand, why you want to let PWMxA= PWMxB, PWMxB= PWMxA during the whole negativeHalf stage? 

And basicly,

zerocrossing1 means shut down all the PWM channels

zerocrossing2 means giving the high frequency channels a fixed duty 0.004

zerocrossing3 means soft start of the high frequency channels, using state_slew_max to control the end of this stage.

look forward to your answers.

BR Emma

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.