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Original question:

AWR1243: A question about rlDeviceDisable and rlDeviceEnable in the DFP example

AWR1243: A question about PMIC in the AWR1243 BOOST

huangyaohui
Intellectual 520 points
Part Number: AWR1243
Other Parts Discussed in Thread: MMWCAS-RF-EVM

Hello!

I see the description of PGOOD and PMIC_enable in the user's guide about AWR1243BOOST.

First, in the word, PGOOD could indicates the state of the onboard VIO supply for the AWR device coming from
the onboard PMIC. I think only if the PGOOD is active, the device can work. Is right? But I couldn't know what's the state of PGOOD is active,and I couldn't find it in the datasheet of LP87524B/J/P-Q1.

Second , in the word, PMIC_enable could be used to shut down the PMIC and AWR device. When I connect PMIC_enable with GND and then disconnect them, there is nothing happened.

Can you give me some advice how to use two signal?

Thanks.

  • 0
    TI__Genius 17820 points

    Hi , 

    The PGOOD from each LP87524P device is "good" when at logic high, in this case 3.3V. 

    PGOOD is also output from the MMWCAS-RF-EVM board to any attached host board. A host board can use this information to sense when the AWRx system should be powered on. PGOOD is not meant to be a control input into into the MMWCAS-RF-EVM. 

    In the MMWCAS-RF-EVM schematics, you can checkout U6 (AND gate) and see that it is used to combine the LP87524P PGOOD output with the host processor provided NRESET for AWRx #1. This is used to assert the NRESET signal (bring it to GND) if PGOOD goes low and to delay NRESET de-assertion until the PGOOD is valid. 

    Thanks,

    -Randy

  • 0 in reply to Randy Rosales
    Intellectual 520 points

    Thank you very much for your reply.

    I have known the workmode of PGOOD. I also want to know how to use the PMIC_enable signal to control PMIC.

    The following is a description of EN1, and EN1 is connected to the pin of EN1.

    From the word ,I think the PMIC is enabled when EN1 has a rising edge, and PMIC is disabled when EN1 has a falling edge. But  I didn't implement it.

  • 0 in reply to huangyaohui
    TI__Genius 17820 points

    Hi, 

    Yes. Bringing the LP87524P EN1 pin "high" will enable all 4 buck converters to operate. In the case of the MMWCAS-RF-EVM is done with a pull-up when 5.0V power is applied. 

    Thank you,

    -Randy