• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 2 answers
  • Subscribers 63 subscribers
  • Views 292 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.

TPS65185: Power management forum

Monisha M
Prodigy 150 points
Part Number: TPS65185
Other Parts Discussed in Thread: TPS7A39

Tool/software:

Hi Team,

We are using the TPS65185 PMIC for our EINK 10.3" Display (EC103TH2). The typical voltage of the VGL(Gate Negative supply) is -22V. From the datasheet it is noted that minimum voltage of VEE_IN(input supply for charge pump) is -20V. Is it possible to adjust the negative charge pump supply to -22V? What is the maximum voltage that can be achieved from the charge pump of TPS65185? Could you please comment on this? The voltage level of the display is provided below for your reference. 

  • 0
    TI__Guru* 81035 points

    Hi Monisha,

    I have seen this question posted 3 times today on E2E from different folks. Unfortunately it is not possible to adjust the CP2 output outside of the range in the datasheet.

    Best regards,

    Matt

  • 0 in reply to Matt Sunna
    Prodigy 150 points

    Hi Matt,

    Sorry for the inconvenience made, we will make sure multiple queries related to this won't be repeated.

    I am confused and trying to understand, because if -20V cannot be varied to -22V we will have to change the PMIC.
    In TPS65185 there are two charge Pumps CP1 and CP2 and there are feedback resistors for both the charge pumps. If the output voltage of positive charge pump can be adjusted why is it not possible to adjust the negative charge pump which has same feedback resistors and both of them have same input voltage of 16V.
    The absolute maximum rating of VEE-DIS(Discharge pin of negative charge pump) is -30V, so is there a chance for CP2 to rise above 20V. Could you please provide a clarification on this?
    If this is not at all possible can we add an additional Diode and Capacitor network to increase the charge pump voltage and VEE_DRV will drive that cap too. If the voltage is above 22V can we use a Zener diode regulator to limit the voltage, is it possible, is there a permanent solution for this?
    Could you please suggest a solution on this or suggest any alternate part that can achieve -22V?

    Best Regards,

    Monisha M

  • 0 in reply to Monisha M
    TI__Genius 12127 points

    Hi Monisha, 

    Technically it could be possible by adjusting the feedback resistor on the CP2 network, like with the CP1. 
    However, this has not been under extensive testing, and as such, it cannot be recommended by TI.
    This can be done at your own discretion, but there is no guarantee the device will perform as expected.
    The maximum value we recommend for applications is -20 V. 

    Unfortunately I do not believe we have a single-chip solution for this.
    My recommendation would be to use another regulator like the TPS7A39 along with the TPS65185 to separately power the Gate Negative & Positive Supply. The TPS7A39 can safely achieve up to -30V.

    Best Regards, 
    Sarah

  • 0 in reply to Sarah Lao
    Prodigy 150 points

    Hi Sarah,

    Thank you for the clarification and suggestion.

    Best Regards,

    Monisha M