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jayashan
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hello there,
I design PCB with TLF35584 with high-frequency mode. After SPI communications and all other requirements are ok then Vprereg has a 1V voltage drop when I check using an oscilloscope. Here i attached photos of the Vprereg and Quc voltage shows in oscilloscope.

Kindly can anyone guide me on how to solve this problem?

thank you 

oscilloscope  viewoscilloscope view

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Polimera
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25 solutions authored 100 sign-ins 50 replies posted

Hi ,

That is the Error because of INIT timer.  Because there is no SPI communication there is no watchdog signal to the PMIC from controller which will leads to INIT timer error. Please pull up the MPS pin and check the waveforms. MPS will mask the watchdog , INIT errors.

Regards,

Kranthi

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Polimera
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25 solutions authored 100 sign-ins 50 replies posted

Hi Jayashan,

Thanks for the query. Could you please elaborate the query? 

What is the voltage value of Vprereg & Vquc before and after SPI Communication? 

Along with that could you please let us know how much load at Vprereg & Vquc

 

Regards,

Kranthi

 

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jayashan
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Thank you for the quick response,

Sorry for the inconvenience I mistakenly added another photo and I added it here a actual photo of

V prereg a Quc oscilloscope view. Even no SPI configuration is done Vprereg & Vquc have 1V drop And no load applies for the V prereg & V quc .wakeup pin is connected to the 12V with a series resistor 10Kohms resistor and enable pin connected to the ground.

 

WhatsApp Image 2023-03-28 at 14.29.29.png

V prereg voltage -5.8V

when have a drop V prereg voltage -around 4.5 V

V quc - around 3.3V

when having a drop in V prereg , V quc goes to 0V

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Polimera
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25 solutions authored 100 sign-ins 50 replies posted

Hi Jayashan,

 Could you please let us know in which mode your PMIC  is operating? Could you please share your schematic?

Vprereg functional range is 5.65 to 5.95V. In case your voltage is below this, then you won't get any other post-regulator voltages.

Regards,

Kranthi

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thank you for the response,

PMIC operating in INIT STATE. I will attach the screenshot of the schematic here. 

 

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Polimera
Moderator
Moderator
Moderator
25 solutions authored 100 sign-ins 50 replies posted

Hi ,

That is the Error because of INIT timer.  Because there is no SPI communication there is no watchdog signal to the PMIC from controller which will leads to INIT timer error. Please pull up the MPS pin and check the waveforms. MPS will mask the watchdog , INIT errors.

Regards,

Kranthi

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