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TIDM-DC-DC-BUCK: In peak current control mode, the cmpss trigger comes in after deadtime module, how to insure the deadtime at turn off?

Part Number: TIDM-DC-DC-BUCK

In peak current control mode, the pwm is turned on at beginning of the period, and turned off when peak current triggers. The cmpss trigger comes in after deadtime module, how to insure the deadtime at turn off?

Thanks!

  • Please check P.41 of user guide.

    CMPA is determined by inductor feedback and this does not come from digital compare module. The analog comparator in ADC get the feed back from the inductor determines duty (CMPA)

  • Oh my gosh, you are completely wrong. 

    In peak current mode, it is the cmpss output determines when it turned off. inductor current goes into cmpss NOT ADC, it is configured as cmpss not ADC. 

    check out fig10 in manual, it says cmpss;

    check out code, when config PwM in BUCK_HAL_setupSyncBuckPwm(), only in VMC, output A turned off according to cmpA. In BUCK_HAL_setupSyncBuckPcmcTripAction(), outputA is configured to turn off at T1 event, 

    My question is current mode turn off!!

  • Sorry I meant Analog circuit not ADC.

    Once CMPA is determined by inductor feedback, it turns off ePWMA and ePWMA output is fed to dead band module and it generated ePWMB in complementary manner.

    Again, CMPSS is not in DC(digital compare) that you highlighted. CMPSS in analog circuit.

  • CMPA is completely not used in peak current mode control.

    Please checkout this diagram how the modules feed into each other: cmpss output goes into DC through EPWM xbar and then goes into Trip Zone to turn off the outputA.

    Please read function BUCK_HAL_setupSyncBuckPcmcTripAction(), it configures epwmxbar DC module and the trip action.

  • In either way, your AQ module determines ePWMA signal and it goes into deadband module and generate complementary signal. T1 event is also the input to AQ and it turns off the switch.

  • I see, DC output goes to T1 goes to AQ.

    You also need a better understanding of the peripheral structure and TIDM-BUCK.

    'In either way' is not a good attitude.