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TIDA-00961: some question about schematic

chen wei lun
Intellectual 330 points

Part Number: TIDA-00961
Other Parts Discussed in Thread: TMS320F280049, TMS320F28075

Recently reading the design file of TIDA-00961, the following problems were about in the SCH file

Q1:What are those signal (Blank、ACTIVE_PWM1) for ?

Q2:I’m confuse about the component (R211、R204、C202、C205)  ,because I can’see the component at symmetry circuit(AUX2A、AUX2B)

Q3: This circuit is for the input current sensor to scale up the output to a level suitable for the controlCARD, and I want to know how to determine the G_AC_I signal ?

Q4:I know the R419、R422 are for external hysteresis,but why need to parallel C419 with R422

Q5:What the CROSSOVER signal for ?

Q7:Why need to parallel capacitor C406、C415 with comparator?

Q8:What the ZVS1、ZVS2 for ?

Thanks!!

  • 0
    TI__Expert 3860 points
    Hi Chen,

    The answers to your questions are given below:
    Q1: These signals are used internally for getting information on whether the circuit is doing ZVS or not.
    Q2: You can see that the pins 2 & 4 of U201 are connected to same point (REF). So it is symmetrical. The components you indicated are used for setting a reference voltage threshold at these pins.
    Q3: This is a digital 1 or 0 signal to set the gain of the current amplifier. THe feedback resistor is either R222 or R221||R222 depending upon this signal is 1 or 0.
    Q4: This is a speed up capacitor. For any sudden change at output, there will be a large positive feedback instantaneously. In a short time the positive feedback will settle to the value set by R422.
    Q5: This signal is presently not used in the code. It can be used for knowing whether the inductor current has crossed zero or not (indirectly from the switch node voltage).
    No Q6.
    Q7: Same answer as Q4. They are speed up capacitors.
    Q8: This is an alternate scheme to sense ZVS. Presently not used.

    Regards,

    Salil
  • 0 in reply to Salil
    Intellectual 330 points
    Hi Salil, Thanks you for your reply!!
    And I want to know the turn ratio of the L102(AUX2A、AUX2B)、L103(AUX1B、AUX1A)
    Does the pin number on the HSEC9-160-01-L-DV-A-BL correspond to the TMS320F280049?
    Thanks again!
  • 0 in reply to chen wei lun
    TI__Expert 3860 points
    Hi Chen,

    The ratio is 6:1. Please see the inductor datasheet at www.precision-inc.com/.../019_8903_00R.pdf
    The pin numbers on the HSEC connector corresponds to the HSED daughter card in the TMS320F280049 development kit.

    Regards,

    Salil
  • 0 in reply to Salil
    Intellectual 330 points

    Hi Salil, Thanks you for your reply!!

    Is ZVS1_2、ZVS2_2 in TIDA-00961's document used to achieve valley switching function mentioned in the technical document of TMS320F280049 ?
    Is Valley Switching function mention in TMS320F28075 Technical Reference Manual page.1610 as same as TMS320F280049 Technical Reference Manual?