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TPS25730: TPS25730D - I2C control

Aleksandrs Zaslavskis
Prodigy 10 points
Part Number: TPS25730
Other Parts Discussed in Thread: TPS25751

Tool/software:

Description:

1. We use the TPS25730D (USB PD Controller).
2. A voltage divider is connected to the ADCIN1 input - 100k on LDO_3V3
and 5.1k on GND to program the min. voltage of 9V.
3. Only a 100k resistor on LDO_3V3
is connected to the ADCIN2 input to program the max. voltage of 20V.
4. Voltage dividers are connected to the ADCIN3 and ADCIN4 inputs
as in p. 2 to program the operating current of 1A and the max.
current of 3A.
5. Only a capacitor (bypass capacitance).
10 uF is connected to the VIN_3V3 input.

Question. Is it possible (and how) to change the operating voltage to 9V, 12V or 15V via I2C if the voltage source produces up to 20V.

  • 0
    TI__Mastermind 37855 points

    Hi Aleksandr,

    The only way to change the negotiated voltage is to change the ADCIN2 divider which is sampled on power up. You cannot change the supported sink PDOs in realtime.

    The way the TPS25730 works is it will configure it's sink PDOs on boot up based off of the ADCINx config. When negotiating a contract with the source, it will attempt to negotiate the highest power contract shared between the source and itself. In this case, if the source offers 20-V and the TPS25730 supports 5, 9, 15, and 20-V, it will always go for 20-V.

    The only way to change this with the same adapter is to lower the max voltage setting in ADCIN2 to be the voltage you want. This is not configurable while the tps25730 is still powered.

    If you need to be able to change this in realtime, you would need to switch to the TPS25751, which can configure it's sink PDOs over I2C in runtime.

    Thanks and Regards,

    Chris

  • 0 in reply to Christopher Lim1
    Prodigy 10 points

    Dear Chris

         Thanks for answer.  It looks we've made wrong choise -  we needed TPS25751 to change configuration in real time.

    Issue solved.

    Alex