TPS63000: Device cannot work normal when VINA capacitor is 0.1uF

Statham Su

Genius 4840 points

Part Number: TPS63000

Hello Sir:

We are using TPS63000.

But that device is abnormal when using 0.1uF of VINA.

Please refer our schematic and layout as below.

If our C227 is 0.1uF, please refer our measure waveform as below.

Ch1 VIN, Ch2 L1, Ch3 L2 and Ch4 is VOUT.

If our C227 is 10uF, please refer our measure waveform as below.

Ch1 VIN, Ch2 L1, Ch3 L2 and Ch4 is VOUT.

Please help to provide your recommendations for us and let us know how to fix this issue.

Thanks a lot.

0 Tao Zhang over 2 years ago

Hi statham,

according your attached waveform, i think the abnormal working is caused by low Vin but not the CAP C227.

could you increas the input voltage and check if it will be normal?

Regards

Tao

0 Statham Su over 2 years ago in reply to Tao Zhang

Genius 4840 points

Hi Tao:

Tested condition as below:

INPUT: USB power from PC

OUT: 5V for RFID device and buzzer, normal is about 280mA.

Please refer the waveform as below.

When we use 0.1uF, that VIN and VINA will drop to 1.8V.

When we use 10uF, that VIN and VINA will keep 5V.

Please let us know which points we need to check.

Thanks a lot.

0 Tao Zhang over 2 years ago in reply to Statham Su

Hi statham,

Got it, i think It should be the chip started too fast and caused the USB to be pulled and crashed.

replace C227 to a 10uF cap is a good idea, any concern?

Regards

Tao

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