TPS65131: large ripple at positive output on symmetrical DC-DC converter using TPS65131 in power saving mode

Carlos Silva85

Part Number: TPS65131

Dear All,

I have a customer using the TPS65131 in a split rail application with Vin = 3.6 - 4.2V and Vout = +/-12V.

When using power saving mode, the device shows a very large ripple, which somehow seems to improve by changing the feedforward capacitor.

The large ripple only shows on the positive output, not on the negative.

I do have some more information, but would like to keep it private. Can I have some suggestions as to what is causing this irregular behavior?

Kindest Regards,

Carlos

over 8 years ago

0 Diaara over 8 years ago

TI__Intellectual 2805 points

Hello Carlos,

The ripple in power-save mode is in general higher than in continuous-conduction mode. This is due to the fact that in this mode the device switches only when the output voltage falls below a threshold value: it switches for a few cycles until the correct output voltage is obtained then stops.

To come back to your specific problem, what is the ripple value you qualify as "very large ripple"? And what are the loads and output capacitors values?

You can send me the additional information privately via direct message here or via email.

Best regards,

Diaara