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TPS61022: TPS61022 Questions

Tristan Arian
Prodigy 210 points
Part Number: TPS61022

Hello,

For this specific chip, I am wanting to get a corresponding DC power source (Lipo) that would fit the requirements. I am thinking about 3.7V with 4000mAh capacity. My load varies and first I see that I can output a continuous current of around 0 to 3A. For higher loads, the input voltage should not be an issue but for those that can take 3A continuous, what is the lowest input voltage to satisfy this? From reading the datasheet I belive it said 2.7V. Once it hits this what will happen to the output current. 

Best,

Tristan

  • 0
    TI__Guru* 75955 points

    Hi Tristan,

    Thank you for posting.  Our experts supporting this device are currently on national holiday and they will be back by Oct. 9th.   Let me try to answer your question here. 

    You need to tell what is your output voltage.   The IC has a peak current limit at 8V, which is the switch max current.  Above that you will kit the peak limit and the duty cycle will be truncated, hence you will see the output voltage starts to lose output regulation. The inductor also affects the peak current.   The TPS61022 can operate down to 0.5Vin according to datasheet.    Equations (1)-(3) can be used to predict your min Vin to support  your 3A load current.  

    Hope this clarifies.

    Thanks,

    Youhao Xi, Applications Engineering

  • 0
    TI__Mastermind 34201 points

    Hi Tristan,

    Our expert Youhao has answered your question of what will happen if input voltage is very low. Please tell us the desired output voltage.

  • 0 in reply to Youhao Xi
    Prodigy 210 points

    Youhao Xi,

    The output voltage I am looking for is 5V and 3A. The input voltage will start off as 3.7V with 4000mAh. 

    Best, 

    Neima

  • 0 in reply to Tristan Arian
    TI__Mastermind 34201 points

    Hi Neima,

    TPS61022 should be able to output 5V/3A from a Lithium-ion battery. Below is the efficiency curve tested on TPS61022 EVM with Vout setting at 5V. If the device hits the switch current limit(Vin decrease), the output voltage will drop from 5V.

  • 0 in reply to Zack Liu
    Prodigy 210 points

    Zack,

    So I could use a lithium polymer battery to accomplish this then? In this application, I see that says the input voltage range is between 0.5V to 5.5V but for the parameters, it says the range for Vin is 2.7V minimum. So my question is with a 3.7V input max, how long can I sustain a constant 5V 3A output. In another case, let's say another load needs around 1-2A with 5V output also. Would I be able to sustain this much longer than outputting 3A with this setup below?

    Best,

    Neima

  • 0 in reply to Tristan Arian
    TI__Mastermind 34201 points

    Hi Neima,

    The figure 16 shows a typical schematic in the condition listed in table 1. It could output 5V/3A in the Vin range of 2.7V to 4.35V.

    If the output current is lower, such as 5V/2A, the minimum Vin range could be lower than 2.7V until it triggers switch current limit.

    In another word, the minimum Vin voltage depends on when the device triggers switch current limit.