TPS65217: TPS65217B LDO1 wrong voltage with VIO

iris kang

Prodigy 30 points

Part Number: TPS65217
Other Parts Discussed in Thread: AM3352

Hi Team,

I'm using TPS65217B PMIC.

TPS65217B VIO connected to VLDO1(1.8V).

PGOOD connected to nPWRONRST of AM3352.

nPWRONRST is power domain 3.3V (VDD6SHV)

Often 3 seconds after turning on the system, VLDO1 voltage changed 1.8V to 2.2V. (7 out of 15 sets are 2.2V, 8sets 1.8V)

I2C is not controlled within the system.

When nPWRONRST is power domain 3.3V, VIO is using only 3.3V?

Based on the "SLVU551I", VIO connected to LDO1 is not problem.

Could you help me to debug this issue?

SLVU551I -Powering the AM335x with the TPS65217x

over 3 years ago

0 Emily Kong1 over 3 years ago

TI__Expert 3350 points

Hi Iseori,

Can you provide a schematic and layout of your system?

Best,

Emily

0 iris kang over 3 years ago in reply to Emily Kong1

Prodigy 30 points

Attach the related circuit. Can I attach the layout as an image?

0 Emily Kong1 over 3 years ago

TI__Expert 3350 points

Thank you Iseori,

Can you also attach preliminary scope shots of VIO, VIN, PGOOD, LDO_PGOOD, VLDO1? I will be back in the office 4/12 and will take a look at your feedback then.

Best,

Emily

0 iris kang over 3 years ago in reply to Emily Kong1

Prodigy 30 points

Thank you Emily,

I attach a scope shots.

Best regards,

Iseori

+1 Kevin LaRosa over 3 years ago in reply to iris kang

TI__Genius 17380 points

Hello,

Emily is OoO today and will respond back Monday or Tuesday.

The most common reason for an LDO output to rise is for some IC on the net back-powering it from another supply. If you have any components powered on VIO that have both 1.8V and 3.3V input for example, they may be backfeeding. One way to test this is to remove ICs on the 1.8V net one at a time.

Power management

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TPS65217: TPS65217B LDO1 wrong voltage with VIO