TPS63000: Behavior when FB divider resistor (R1、R2) trouble

Katsu Matsunaga

Part Number: TPS63000
Other Parts Discussed in Thread: TPS63020

Hello team,

My customer is verifying the behavior when R1 removing or R2 shorting between GND and FB. In these case, Vout is calculated as max value from equation 1 in datasheet. This should make maximum duty cycle, right?

The customer got scope short of Vout on their target board. This waveform is repeatedly output.

Is this expected behavior?

After this experiment, Vout got normal operation with correct R1 and R2 resister. This means the circuit works well.

Could you please give your comment.

Best regards,

Katsu

over 4 years ago

0 Minqiu Xie over 4 years ago

TI__Mastermind 21565 points

HI Katsu:

Sorry for keep you waiting.

Please allow me check with team about the details.

0 Minqiu Xie over 4 years ago in reply to Minqiu Xie

TI__Mastermind 21565 points

Hi Katsu:

The TPS63000 doesn't have over voltage protect. So if the feedback resistance goes wrong, the Vout can be much higher than target.

According to the test in my lab, the Vout reaches 8V with light load. As it can exceed the absolutely maximum rating of the device, there is a risk to damage the circuit.

If customer do need over voltage protection, we suggest TPS63020 and TPS6380x devices

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TPS63000: Behavior when FB divider resistor (R1、R2) trouble