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TPS61022: TPS61022

user744376
Intellectual 420 points
Part Number: TPS61022
Other Parts Discussed in Thread: LMR33610

I intend to use the TPS61022 to boost the voltage from a super capacitor to 5.05V at the output.

In order to "bridge" the charge time of the super capacitor I will use the LMR33610 to provide the 5.05V output during the charge time of the super-cap.

Questions:

This "back-drive" of voltage across the TPS61022 during the 60s charge time how will this effect the IC?

What level of current will run back from the output pin into the TPS61022 when the input voltage (super capacitor) is 0V?

  • 0
    TI__Mastermind 34231 points

    Hi,

    Thanks for showing interest in TI boost converter products.

    During the 60s supercap charge time, if TPS61022 is configured as MODE logic low and configured TPS61022 programmed output voltage little bit lower than output of LMR33610, for example, LMR33610 Vout = 5.2V and TPS61022 Vout =5.0V. So TPS61022 is in the state of PFM mode. In this mode, both the high and low side switch of TPS61022 is turned off. There will be no current from output pin of TPS61022 to input voltage (super capacitor).

    What's the desired output current of TPS61022 circuit and what's the super capacitor operating voltage range?

  • 0 in reply to Zack Liu
    Intellectual 420 points

    Hi Zack,

    First thank You for the fast and helpfull reply.

    TPS61022 Vout= 5.1V Iout= 0.6A - 0.8A, MAX 1.0A

    Vin (from SuperCap): start 4.6V, stop 1.0V

    Regards,

    Jørgen

  • 0 in reply to user744376
    TI__Mastermind 34231 points

    Hi Jorgen,

    Ok. Thanks for providing the background information.

    Below is the schematic of TPS61022 EVM. To make sure the circuit is still stable at low Vin range, 1.0V-1.5V, it's needed to put a 100uF aluminimum electrolytic capacitor at output in parallel with C4~C6. In the meanwhile, put a feedforward capacitor in parallel with R1. The capacitance would be 100pF (a 100kohm resistor is recommended to put in series with 100pF to avoid noise coupled into feedback loop). Set the output voltage of LMR33610 1% higher than TPS61022 Vout so that TPS61022 always work at PFM.

    Please follow the TPS61022 layout guideline in datasheet.