TPSM82912: Output Voltage

Yuta Nishie

Genius 5490 points

Part Number: TPSM82912

Tool/software:

Hi,

I apologize for the late reply.

The thread was closed due to my late reply. I will post a new one.

https://e2e.ti.com/support/site-support-group/site-support/f/site-support-forum/1510439/tpsm82912-output-voltage/5817743?tisearch=e2e-sitesearch&keymatch=%25252525252525252520user%2525252525252525253A460063#5817743

I replaced the IC and evaluated it, but the symptom did not improve. Would it be possible for you to tell me the items to check?

While replacing the IC, I also took the following measures.

・NR/SS pin connection method changed from GND to NC
・22uF was added to the output capacitor to total 88uF
・FB resistance constant changed (R285:16 kΩ→27 kΩ, R287:3 kΩ→5.1 kΩ)

Best Regards,

Nishie

7 months ago

0 Yuta Nishie 7 months ago

Genius 5490 points

Hi,

When I connected the evaluation board to the existing circuit and checked, it output 5V.

However, when I removed the C18 connected to the NR/SS pin of the evaluation board and connected it to the GND, the output voltage became 0V.

Is it wrong to connect the NR/SS pin to the GND?

Best Regards,

Nishie

+1 Haseen Reddy Siripi Reddy 7 months ago in reply to Yuta Nishie

TI__Genius 12290 points

Hi Yuta,

If you connect the SS pin to GND i.e internal reference voltage you are connecting to GND so due to this the reference voltage is zero and device will not switch.

Regards,

Haseen.

0 Yuta Nishie 7 months ago in reply to Haseen Reddy Siripi Reddy

Genius 5490 points

Hi Haseen-san,

Thank you for your support.

Since there is an NR/SS pin in the Vref output of the internal circuit, is it correct to understand that when the NR/SS pin is connected to the GND, the voltage of the + pin of GM becomes the GND level and the IC does not operate?

...

Best Regards,

Nishie

+1 Haseen Reddy Siripi Reddy 7 months ago in reply to Yuta Nishie

TI__Genius 12290 points

Correct.

The Error Amplifier internal non-inverting terminal (+) is GND means no output from the Buck.

Regards,

Haseen.

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TPSM82912: Output Voltage