• State
  • Locked Locked
  • Replies 4 replies
  • Subscribers 64 subscribers
  • Views 231 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS543B20: Transient Response of TPS543B20

Zhanpeng Li
Intellectual 2140 points
Part Number: TPS543B20

Hi team,

for now, I have some questions about TPS543B20:

1)through webench design, the output C is recommended as 1mF.However,thourgh reference design, it is suggested as 470uF. whether the output C is impact the index of Transient response?

2)when talked about Transient response, do we have some specific number of files to measure?

  • 0
    TI__Intellectual 2460 points

    Hi Zhanpeng,

    I am not quite sure understand both questions. Can you please clarify more on "the index of transient response" (is that mean undershoot) and "number of files to measure" (is that how to measure)?

    Kit

  • 0 in reply to Henry Nguyen
    TI__Intellectual 2140 points

    Hi Kit,

    For " transient response", it should contain undershoot and recovery time;

    For "number of files to measure", I mean that how to measure the quality of transient response?

    BR

    Brandon

  • 0 in reply to Zhanpeng Li
    TI__Intellectual 2460 points

    Hi Brandon,

    The transient response is related to the LC filter stage and amount of load step. The datasheet included the output capacitance calculation (equation 9) and typical transient response waveform (Figure 7 and 19).

    The quality of transient response is based upon LC filter, current step, and compensation. Since this device is an internal compensation with allow RAMP pin to select the zero to adjust with LC filter frequency. Table 3 in the datasheet listed the values of capacitor. This capacitor along with internal 300K-OHM will set the zero. So, the choice of this zero is about 3 times of LC filter frequency.

    Hope this help.

    Kit

  • 0 in reply to Henry Nguyen
    TI__Genius 14455 points

    Hi Zhanpeng

       The value of Cout depends on the Vout ripple spec, the load transient step size and the load transient undershoot/overshoot requirement. The TPS543B20 WEBENCH model gives you flexibility to design your Cout to meet your requirements.

    The designs could be different depending on the default specs for the reference design and the WEBENCH design.

    Please let us know if you have more questions.

    regards,

    Gerold