LMR33630: Use MCU to control LMR33630BDDA ON/OFF

Mike Peng

Part Number: LMR33630

My customer used MCU to control LMR33630BDDA ON/OFF, they detected abnormal voltage(1.4Vdc) which output suppose to be set 0Vdc for OFF status. I suggested engineer to adjust the peripheral parameter and it

appearred less but still exist. Is this phenomenon possibly related to the MCU I/O initialization?

over 6 years ago

0 Timothy Hegarty over 6 years ago

TI__Guru 73492 points

Hi Mike,

Is the schematic available?

Regards,
Tim

0 Frank De Stasi over 6 years ago in reply to Timothy Hegarty

TI__Guru 72525 points

Yes, we need to see the schematic.
There should be no voltage on EN that is generated from within the device.

0 Mike Peng over 6 years ago in reply to Timothy Hegarty

Expert 1060 points

Sorry, SCH is not available to be posted on website, but I have checked the mainboard with engineer in spot. I found the I/O connected to 'EN' pin is also public used as 'CLK' signal input to another IC, it kept sending out abormal PWM signal even when LMR33630 was supposed to be closed. Then I told the software engineer to check the initialization of this I/O pin, 'CLK' signal was always sending out clock PWM when 'EN' was set to 'off'. Changed this pin into correct mode and LMR33630 worked normal.

0 Frank De Stasi over 6 years ago in reply to Mike Peng

TI__Guru 72525 points

OK; this sounds like it is fixed.
I will close this post

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LMR33630: Use MCU to control LMR33630BDDA ON/OFF