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TPS62082: TPS62082 snooze mode question

Alessandro Cortese
Prodigy 10 points

Part Number: TPS62082
Other Parts Discussed in Thread: TPS62843, TPS62825, TPS628301, TPS62840

Good morning,

I have a question regarding the TPS62082 Snooze Mode operation.

According to the datasheet, Snooze Mode is intended to improve efficiency at very low load currents, typically below 2 mA, by reducing the device quiescent current and allowing the converter to periodically wake up only when the output voltage drops by approximately 3.5%.

Could you please clarify what happens when Snooze Mode is enabled while the load current is consistently above 2 mA?

Thank you for your support.

Best regards,

 

Alessandro Cortese

 

 

  • 0
    TI__Mastermind 22150 points

    Hi Alessandro,

    It is recommend to not use snooze mode if load currents are higher than 2mA. Since internal bias currents are reduced with snooze mode, response to load transients can be slower. It can also be that the device regulates to the target output and switches off till the output falls below 3.5% again.

    You might also want to check out some of our newer parts: ultra low IQ - TPS62840, TPS62843 or 1A parts - TPS62825, TPS628301. 

    Best regards,

    Varun

  • 0 in reply to Varun John
    Prodigy 10 points

    Hi John,

    thank you for you quick reply. 

    Could enabling snooze mode cause issues for the microcontroller downstream of the regulator?

    At times, the microcontroller draws around 5 mA while performing Bluetooth scanning. There is also a step-up converter with a 3.7 V output used to power a vibration motor, which is activated occasionally.

    So far, I have rarely experienced any issues with this snooze mode configuration enabled, except on a couple of boards a few days ago, where the microcontroller unexpectedly reset. That is the reason why I am contacting you.

    Could this behavior be related to the sleep mode, or are there other aspects of the power supply configuration that I should investigate?

    Thank you for your support.

    Alessandro

  • 0 in reply to Alessandro Cortese
    TI__Mastermind 22150 points

    Hi Alessandro,

    Thanks for the additional info. The MCU current is quite low. How much max current does the boost converter consume? It could be that a sudden load step on the boost may be causing the output of the TPS62082 to dip. The TPS62082 load response can be worse in snooze mode. Do you know at what voltage the MCU resets?

    If possible can you get a scope shot of the TPS62082 output voltage and also the voltage directly at the MCU input pins when the MCU resets? 

    Can you also experiment with snooze mode off and see if the MCU resets? Increasing the output cap at MCU and boost inputs may be also an option to try out. The datasheet says 100uF on the output of TPS62082 should be alright.

    Best regards,

    Varun

  • 0 in reply to Varun John
    Prodigy 10 points

    Hi Varun,

    I am using the TPS61299QDRLRQ1 as a boost converter with the output programmed to 3.7 V. This voltage is used to supply the JYC1434 vibrating motor, whose maximum rated current is 90 mA.

    The vibration function is activated only during alarm conditions and operates periodically, for example with a 100 ms ON / 100 ms OFF pattern.

    To support the pulsed load generated by the motor, we placed a total of four capacitors in parallel at the regulator output:

    • 2 × 330 µF (T520B337M006ATE070)
    • 2 × 47 µF

    Best regards,

    Alessandro

  • 0 in reply to Alessandro Cortese
    TI__Mastermind 22150 points

    Hi Alessandro,

    Ok, it could be caused by the extra load when the motor turns on. If possible you can try probing the output of TPS62082 when the motor is turned on to see how much it undershoots.

    Best regards,

    Varun