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.

Fast voltage change

Other Parts Discussed in Thread: TIDA-00180, TPL0401A-10, TPS54040A, LM10011, LM48580

Dear all.

Our customer is looking for a method to fast change the output voltage on DCDC.
The required change time is not a decision, but probably will be us order.
The load will piezo.(?)
Input voltage is 24V, output voltage is 5V to 22V.(3 point +/- 1.5V)
For example;
Set 10V-> 8.5V-10V-11.5V, set 11V-> 9.5V-11V-12.5V
Do you have any idea?


  • Hello PAN-M,

    There are many ways to change the Vout of a DCDC while operating.
    See the attached application note that shows using a Digital Potentiometer to adjust the feedback network.
    TIDU533 user guide from the TIDA-00180 Design.

    Page 8 shows TPS54040A  DCDC controlled by a TPL0401A-10 DPot .
    Page 14 shows other methods to vary Vout using FET controlled resistor dividers.
    Page 15 shows a DAC LM10011 driven by an MCU to vary Vout.

    These are common methods to achieve what you need.

    Will one of these methods work for you?

    Programmable Output Voltage dPOT TPS54040 tidu533.pdf


  • Thank you for an answer.

    The problem of Dpot is "±20% Resistance Tolerance".
    In addition, the change of us(micro second) transition is difficult at these suggestion.
    How much is the change speed of these suggestion?
    Do you think that an electric discharge is necessary for the output?
    I think that it is difficult to make the timing when the output does not fluctuate.
    Please teach me if you have a method to solve this problem.


  • Hello PAN-M,
    You must define the waveform, sine, square, triangle; the rise fall times; and nature of the load (resistive, capacitive).
    And an overall consideration is the quality of the waveform you need to generate.

    A typical high voltage Piezo driver is the LM48580
    High Efficiency Class H, High Voltage, Haptic Piezo Actuator / Ceramic Speaker Driver
    30Vp-p rated.

    High power transducers are used in Ultrasonic Park Assist Sensor

    Do you have any more information about the waveform and load?
  • Thank you for various suggestion.
    However, our customer requires an output current of 1.5A.
    In addition, our customer does not know the real load because just to make a circuit.
    If I can obtain more detailed information, I will post again.