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PWM周期值相关问题

Other Parts Discussed in Thread: TMS320F28027

制作PWM表的时候发现一个死区设置,请帮忙解决下。谢谢!

  • 您好,请提供更多相关信息:器件型号或参考设计等。谢谢!

  • 主芯片TMS320F28027,EPWM采用PWM2
    周期值3.61,前后死区均为120,A是B的源头
    EPwm2Regs.TBPRD = 3061;


    EPwm2Regs.TBCTL.bit.CTRMODE =TB_COUNT_UPDOWN;
    //这里采用CPMA做源,PWMxB的输出是PWMxA的取反
    EPwm2Regs.DBCTL.bit.IN_MODE = DBA_ALL;
    EPwm2Regs.DBCTL.bit.OUT_MODE =DB_FULL_ENABLE;
    EPwm2Regs.DBCTL.bit.POLSEL = DB_ACTV_HIC;
    EPwm2Regs.AQCTLA.bit.CAU = AQ_CLEAR;
    EPwm2Regs.AQCTLA.bit.ZRO = AQ_TOGGLE;
    //P57 设置死区, 互补模式下,需要设置死区
    EPwm2Regs.DBFED = 120; // 死区设置 TBCLKs
    EPwm2Regs.DBRED = 120; //

    现在有两种疑问:
    1.当EPwm2Regs.CMPA.half.CMPA<EPwm2Regs.DBFED 死区设定值时两路PWM输出情况?
    2.当EPwm2Regs.CMPA.half.CMPA<EPwm2Regs.DBRED 死区设定值时两路PWM输出情况?
    3.当EPwm2Regs.DBFED或者EPwm2Regs.DBRED<EPwm2Regs.CMPA.half.CMPA<EPwm2Regs.DBFED+EPwm2Regs.DBRED之和时这种情况死区设定值时两路PWM输出情况?

    4.当EPwm2Regs.DBFED+EPwm2Regs.DBRED>EPwm2Regs.TBPRD-EPwm2Regs.CMPA.half.CMPA>EPwm2Regs.DBFED或者EPwm2Regs.DBRED死区设定值时两路PWM输出情况?
    其实主要是想问当脉宽值小于死区值,以及周期与脉宽值差小于死区值的情况的时候两路PWM输出的情况,谢谢!


  • 其实主要是想问当脉宽值小于死区值,以及周期与脉宽值差小于死区值的情况的时候两路PWM输出的情况,

    如果脉冲宽度小于死区,那么脉冲可以完全被swallowed,也就意味着在该 PWM 周期中是没有脉冲的。 A 和 B 输出仍然是互补的。

  • 谢谢您的解答