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TPS62801: TPS62801 Power Save/PWM mode confirmation.

Lin Hsian
Expert 1580 points
Part Number: TPS62801
Other Parts Discussed in Thread: TPS62802, TPS62806

Hi,

TPS62801

1: VSEL/MODE with external resistor to adjust output voltage, this is Power Save Mode(PWM/PFM), right?

2: VSEL/MODE direct to GND to fixed 1.2V output voltage, this is Forced PWM Mode, right?

3.TPS62801 two typical application.

    (1) VSEL/MODE connect resistor=> Is auto mode depend on loading high/low to adjust output, right?

    (2) VSEL/MODE short to GND dircetly=> Is set output voltage keep 1,2V, right?

  • 0
    TI__Guru*** 146720 points
    Hi Lin,

    Section 8.3.3 in the D/S should explain this. Do you have a specific application need?

    1. Yes. But after startup, a high can be applied at the pin to force PWM mode.
    2. No, PFM is forced.
    3a. Yes, unless the pin is driven high after power up.
    3b. Yes
  • 0 in reply to Chris Glaser
    Expert 1580 points
    Hi Chris,
    Is it means the VSEL/MODE to pull high will be force PWM mode?
    If the pin pull high, how to select output voltage?
    We just want to confirm how to select power saving (PFM/PWM) and force PWM mode.

    Warm Regards,
    Lin
  • 0 in reply to Lin Hsian
    TI__Guru*** 146720 points
    Hi Lin,

    Is something not clear in the D/S? To achieve forced PWM mode, please let the IC read the resistor (don't pull the pin high or low) and then apply a high after startup. What does your application require for Vout and MODE?

    Here are relevant D/S sentences which state this:

    After power up, the pin is configured as an input for Mode Selection. Therefore, the output voltage is set only once. If the Mode selection function is used in combination with the VSEL function, ensure that there is no additional current path or capacitance greater than 30pF total to GND, during R2D conversion.

    A low level at this pin selects Power Save Mode operation, and a high level selects forced PWM operation. The Mode can be changed during operation after the device has been powered up. In device options with output voltage selection (VSEL) function (TPS62801, TPS62802, TPS62806), the Mode selection function is only available after the R2D converter has read out the external resistor.