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TPS62864: How to setup with multiple TPS62864

Jack Shen2
Expert 4515 points
Part Number: TPS62864
Other Parts Discussed in Thread: TPS62684

I have couple questions about TPS62864

1) If I want to use three TPS62684 for three individual power rail (0.8V) , do I need to choose 3 different resistors to get different start-up output voltage and I2C address?

 

 

2) And there are 2 registers to adjust the output voltage. Which one should I choose to modify?

Can I adjust this value in register (namely, the output voltage) in advance since my application needs the voltage other than 900mV?

 

  • 0
    TI__Mastermind 21580 points

    Hi Jack,

    1. If you need I2C communication with all 3 devices, you would have to use different resistors on the VSET/VID pin for the 3 of them. This will give each one a unique I2C address and different output voltages on startup depending on the resistor used.

    2. You have the possibility to use both register banks to set the output voltage after startup. If after startup, VSET/VID pin is low - the 'VOUTRegister 1' controls the output voltage. If VSET/VID pin is high, 'VOUTRegister 2' controls the output voltage. I would suggest to just use the 'VOUTRegister 1' for your application as the resistor connected to VSET/VID will automatically pull this pin to GND after startup.

    Best regards,

    Varun

  • 0 in reply to Varun John
    TI__Expert 4515 points

    Thanks for the reply, Varun. 

    I have a question about the default output voltage. Is there a way to change the default output voltage before power up the device? Here is the scenario. We want to use this device for the 0.8V/1.0A power rail, so the idea is that once the device is power up, then it could support 0.8V/1.0A immediately without setting the register. Is that something TPS62864 could do?   

  • +1 in reply to Jack Shen2
    TI__Mastermind 21580 points

    Hi Jack,

    The default output voltage can only be changed by the resistor connected to the VSET pin.

    Is the following work around a solution to your application scenario? Connect a resistor corresponding to a smaller output voltage (like 0.7V or 0.75V) to the VSET pin (see table 8-1 in the datasheet). Before pulling the EN pin of the device high, you can set the 'VOUTRegister 1' to 0.8V. Then when the EN pin is pulled high and the device starts up, it will first ramp up to the set 0.7V or 0.75V with 1ms ramp time, and then further continue this ramp to 0.8V. The ramp time can be more than the typical 1ms in this case.

    Can all the three 0.8V/1A rails be combined into a single 0.8V/3A rail? TPS62864 can supply up to 4A of output current, and if you have a resistors of 56.2 KOhm to GND on the VSET pin, you will startup with 0.8V.

    Best regards,

    Varun