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TL1963A: query about use in regulation system with battery.

Part Number: TL1963A
Other Parts Discussed in Thread: BQ24070,

Hello good day,

I currently have a vehicle tracking device with the following regulation scheme:

The supply voltage is 9v – 30v, this voltage passes through the LMR23630AFDDAR regulator which regulates the output to 5v, this voltage enters the BQ24070 regulator which delivers an output of 4.4v when there is external power or the battery voltage when there is no external power supply, this voltage is supplied to the TL1963A-33 regulator which regulates at 3.3v

According to the datasheet for the TL1963A-33 regulator, the output voltage regulation is from 4.3v to 20v, which would be within range when external power is present but would be out of range when the backup battery powers the system.

My questions for the experts at Texas instruments are as follows.

Am I using the wrong regulator for 3.3v regulation on this device?

Is it better to use a buck-bost regulator for this case?

  • Hi Jose,

    If the LMR23630AFDDAR outputs 5V when there is an external power supply and the battery outputs 4.4V when there is not an external power supply, I don't see an issue. The minimum input voltage specified in the EC table is 2.5V max at full load and over the full temperature range, and the max dropout voltage under the same conditions is 550mV, so I think there is plenty of margin.



  • Hi Nick, thanks for your reply.

    I think I didn't express myself very well. I clarify below:

    When there is external power, the LM23630 regulator supplies 5V to the BQ24070 regulator and this supplies 4.4v to the TL1963A-33 regulator.

    When there is no external power, the LM23630 regulator does not supply voltage, and the BQ24070 regulator supplies the voltage stored in the battery, that is, 3.9v, which later begins to decrease as the battery discharges. The batteries that I am using have a protection circuit that cuts the power when it reaches 2.7v, obviously the TL1963A-33 regulator will not provide me with a voltage of 3.3v with the 2.7v that the battery can deliver at this point of discharge.

  • Hi Jose,

    I see. So are you looking for a device that outputs 3.3V when its input can be anywhere from 2.7V up to 5V? If so, I believe a buck-boost regulator is closer to what you need.



  • Hello Nick
    Can you recommend me one with similar characteristics current characteristics of the TL1963A? Or can you share documentation to find a regulator that suits my needs?

  • Hi Jose,

    I'll reassign this post to the team that can help with a part recommendation.

    Best regards,


  • Hi Jose,

    Thank you for reaching out and looking for a TI solution.  Our experts are currently on CNY holidays and they will return work next week.  While you are waiting, would you please tell a little more spec of your application like the load current or power level, such that our experts can recommend a suitable device to you in accordance.