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TPS65735 Vcomp function question?

Chen Bogey8
Mastermind 9990 points
Other Parts Discussed in Thread: TPS65735

Dear Sir

As I understand from Datasheet, Vcomp = Vbat *Rbscl1/(Rbscl1+Rbscl2) and used Vcomp voltage to MCU foe monitor Vbat voltage.

But from datasheet page 23, here show VCOMP = 0.5 ×VVLDO + 300 mV, I am not sure what is the formula function.

                                                               Best regards,

                                                                               Bogey

 

  • 0
    TI__Genius 16870 points
    Hi Bogey,

    There are internal resistors that voltage divide the VBAT down for external use. If the VLDO select is chosen to be 2.2V the resistors are per table 2-4. However, if the VLDO select is chosen to be 3V the resistors are per table 2-5. I measured on the bench that there can be some variance so, please note that these values are typical values.

    Other than that, it is a simple voltage divider. VCOMP = VBAT*(R2/(R1 + R2)) with R2 being the bottom resistor to GND.
  • 0 in reply to Michael Green
    Mastermind 9990 points

    Dear Sir

     

    Thanks for your help~

    1)

    May you have suggestion how to control H-Bridge? due to when we provide 120Hz to H-bridge. but the glass always black.

    Vin = 5V(power supply)/ BAT= 3V3 (power supply)   LP/ LN/ RP/ RN = 10V (Glass always close, can't open) 

    (2)

    May TPS65735 limit Battery type? Due to we use power supply and power Vbat 3.2V, TPS65735 can Boost to 10V. but when we use button cell battery. tps65735 can't boost to 10V.

    BAT = 3.28V(button cell battery ST9002)     LP/ LN/ RP/ RN = 4V (Glass can Flash frequency but can't full close, because bust voltage can't reach to 10V)

                                                            Best regards,

                                                                                    Bogey

  • 0 in reply to Chen Bogey8
    TI__Genius 16870 points
    Hi,

    Sorry, I can't help you much with the interface to the glasses. I suggest trying other frequencies and monitoring the outputs of the drivers. Maybe they are not rising and falling fast enough or frequency is too high. Look into the timing of the PWMs together too.

    As for the the input BAT, you can a variety of common batteries with the voltage as specified in the datasheet. A typical consumer grade Li-Ion or Li-Poly should work.