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TPS23754EVM-383: Question about TPS23754

Jimmy Huang
Genius 3055 points
Part Number: TPS23754EVM-383
Other Parts Discussed in Thread: TPS23754,

Hello：

The customer designed according to the reference circuit, and currently has good debugging in all aspects, with stable output. There is one small issue that I need your help with now.

The static power consumption of TPS23754 is relatively high. When there is no load, the power consumption reaches 1.3W, causing the transformer to be relatively hot. May I ask which part of the circuit should be adjusted to reduce power consumption. Thanks！！！

poe1.pdf

  • 0
    TI__Mastermind 30721 points

    Hi Jimmy,

    Thanks for reaching out!
    TPS23754EVM-383 applies active clamping forward converter, and its secondary side applies passive gate driving circuit. The transformer loss and gate driving loss are influenced less by the load current. 1.3W could be a reasonable loss value.

    For the transformer hot, the core loss mainly is related to the switching frequency and excitation voltage at the windings, which are related to flux density. 

    For gate driving loss, for example you have 12-V Zener diode and 2-k resistor to drive Q6. Q6 has Vin/N = 18.5 - 27.5 V. It can have max loss = (27.5 - 12)/2k*27.5 =  213 mW ignoring the switching.

    Best regards,

    Diang  

  • 0 in reply to Diang Xing
    TI__Mastermind 30721 points

    You may increase R2 and R3 to 4k to limit the gate driving loss. But you need to test the gate voltages of Q3 and Q6 to make sure there is no over gate voltages during start up and shut down.  

    Best regards,

    Diang

  • 0 in reply to Diang Xing
    TI__Mastermind 30721 points

    Hi Jimmy,

    I will close this thread for now. Please reply or open a new thread if you have further questions.

    Best regards,

    Diang