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Original question:

Can you provide PMP8740 reference design ?

Can you provide PMP8740 reference design ?

anjana desai
Prodigy 190 points
Other Parts Discussed in Thread: PMP8740

In PMP8740 If I dont want parallel connection of power supply feature then what changes I should do? my email id is engg5@adordigatron.com

Anjana

  • 0
    TI__Expert 5875 points

    Hello Anjana,,

    If you don't need any parallel function, just do not use (do not populate) U14 (and passives), Q36, Q37, Q38, Q39, Q200 (and other components associated), remove the CAN-Bus connectors and remove U5, Q5 and passives.

    On the display and push buttons, just set the power supply as "stand alone".

    Best regards,

    Roberto

  • 0 in reply to Roberto S.
    Prodigy 190 points

    But i want CAN communication. my requirement is i want only dc-dc converter with all protection features and CAN communication

    Anjana

  • 0 in reply to anjana desai
    TI__Expert 5875 points

    Anjana,

    If you don't need parallel functions but want to keep CAN communication, just remove U5, Q5, D22, D5 and related passives, and set the power supply as "stand alone". This way you will have available on the CAN bus all information about output power, voltage, current, status etc.

    If you don't even want precise current limit (needed by a battery charger), but your application is just a power supply, you can remove the current sensing resistor R92, U11 and passives, U1B, Q4, D3 and passives associated to U1B. This way your system will limit the output current according to the current sense transformer T1 and current sense resistor R34.

    Thanks,

    Roberto

  • 0 in reply to Roberto S.
    Prodigy 190 points
    Sir,
    how U1A, U1B circuits are works? please explain.
  • 0 in reply to anjana desai
    TI__Expert 5875 points
    Hello,
    U1A is the voltage loop error amplifier. The network, involving C1, C2 and R3, is the voltage-loop compensation, defining poles and zeroes. The reference of this error amplifier is given on pin 3 of U1A. This reference voltage comes from a square wave (from the microcontroller) PWM; the average value of this PWM, which is its duty cycle times the reference voltage (+5Vref) generates the voltage on pin 3. That means, 0...2V on this pin, is equivalent to a 0...32V on the output of the full-bridge.
    U1B works in the same manner like U1A, but manages the information coming from the output current of the full-bridge, therefore it manages the current loop. The reference, present on pin 5 of U1B, is generated in the same manner like the voltage loop.
    Both voltage and current loops insist on the same point (pin 2 of U2) by or-ing the output voltages of U1A and U1B, by means of D1 and D3.
    Then, the lower voltage of U1A or U1B output, will define whether the converter works in constant voltage or constant current regulation.
    Best regards,
    Roberto